Труды сотрудников ИВМ СО РАН

/ H. Lammer [et al.] // Mon. Not. Roy. Astron. Soc. - 2013. - Vol. 430, Is. 2. - P1247-1256, DOI 10.1093/mnras/sts705. - Cited References: 85. - NVE, KGK, MLK and HL acknowledge the support by the FWF NFN project S116 'Pathways to Habitability: From Disks to Active Stars, Planets and Life', and the related FWF NFN subprojects, S116 606-N16 'Magnetospheric Electrodynamics of Exoplanets' and S116607-N16 'Particle/Radiative Interactions with Upper Atmospheres of Planetary Bodies Under Extreme Stellar Conditions'. KGK, HL and PO thank also the Helmholtz Alliance project 'Planetary Evolution and Life'. ML and PO acknowledge support from the FWF project P22950-N16. NVE acknowledges support by the RFBR grant No 12-05-00152-a. The authors also acknowledge support from the EU FP7 project IMPEx (No. 262863) and the EUROPLANET-RI projects, JRA3/EMDAF and the Na2 science working group WG5. The authors thank the International Space Science Institute (ISSI) in Bern, and the ISSI team 'Characterizing stellar- and exoplanetary environments'. Finally, we thank an anonymous referee for interesting suggestions and recommendations which helped to improve the article. . - 10. - ISSN 0035-8711РУБ Astronomy & Astrophysics

Аннотация: The discovery of transiting 'super-Earths' with inflated radii and known masses, such as Kepler-11b-f, GJ 1214b and 55 Cnc e, indicates that these exoplanets did not lose their nebula-captured hydrogen-rich, degassed or impact-delivered protoatmospheres by atmospheric escape processes. Because hydrodynamic blow-off of atmospheric hydrogen atoms is the most efficient atmospheric escape process we apply a time-dependent numerical algorithm which is able to solve the system of 1D fluid equations for mass, momentum and energy conservation to investigate the criteria under which 'super-Earths' with hydrogen-dominated upper atmospheres can experience hydrodynamic expansion by heating of the stellar soft X-rays and extreme ultraviolet (XUV) radiation and thermal escape via blow-off. Depending on orbit location, XUV flux, heating efficiency and the planet's mean density our results indicate that the upper atmospheres of all 'super-Earths' can expand to large distances, so that except for Kepler-11c all of them experience atmospheric mass-loss due to Roche lobe overflow. The atmospheric mass loss of the studied 'super-Earths' is one to two orders of magnitude lower compared to that of 'hot Jupiters' such as HD 209458b, so that one can expect that these exoplanets cannot lose their hydrogen envelopes during their remaining lifetimes.


Доп.точки доступа:
Lammer, H.; Erkaev, N.V.; Еркаев, Николай Васильевич; Odert, P.; Kislyakova, K.G.; Leitzinger, M.; Khodachenko, M.L.

[Text] / M. Ampferer [et al.] // Ann. Geophys. - 2010. - Vol. 28, Is. 3. - pp. 779-787. - Cited References: 30. - This work is supported by grants 07 05 00135, 09-06-91000 from the Russian Foundation for Basic Research and by the Program 16.3 of the Russian Academy of Sciences. Additional support is due to the Austrian "Fonds zur Forderung der wissenschaftlichen Forschung" under Project I193-N16 and the "Verwaltungsstelle fur Auslandsbeziehungen" of the Austrian Academy of Sciences. The authors are grateful to the referees whose comments helped considerably to improve the paper. . - ISSN 0992-7689РУБ Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences

Аннотация: It is well known that lithospheric electromagnetic emissions are generated before earthquakes occurrence. In our study, we consider the physical penetration mechanism of the electric field from the Earth's surface, through the atmosphere-ionosphere layers, and until its detection in space by satellites. A simplified approach is investigated using the electric conductivity equation, i.e., del((sigma) over cap.del Phi) = 0 in the case of a vertical inclination of the geomagnetic field lines. Particular interest is given to the conductivity profile near the ground and the electric field distribution at the Earth's surface. Our results are discussed and compared to the models of Pulinets et al. (2003) and Denisenko et al. (2008). It is shown that the near ground atmospheric layer with low conductivity decreases the electric field penetration into the ionosphere. The model calculations have demonstrated that the electric field of lithospheric origin is too weak to be observed at satellite altitudes.


Доп.точки доступа:
Ampferer, M.; Denisenko, V.V.; Денисенко, Валерий Васильевич; Hausleitner, W.; Krauss, S.; Stangl, G.; Boudjada, M.Y.; Biernat, H.K.

[Text] / N. V. Erkaev [et al.] // Astron. Astrophys. - 2007. - Vol. 472, Is. 1. - P329-334, DOI 10.1051/0004-6361:20066929. - Cited References: 26 . - ISSN 0004-6361РУБ Astronomy & Astrophysics

Аннотация: Context. A study of the mass loss enhancement for very close "Hot Jupiters" due to the gravitational field of the host star is presented. Aims. The influence of the proximity to a planet of the Roche lobe boundary on the critical temperature for blow-off conditions for estimating the increase of the mass loss rate through hydrodynamic blow-off for close-in exoplanets is investigated. Methods. We consider the gravitational potential for a star and a planet along the line that joins their mass centers and the energy balance equation for an evaporating planetary atmosphere including the effect of the stellar tidal force on atmospheric escape. Results. By studying the effect of the Roche lobe on the atmospheric loss from short-periodic gas giants we derived reasonably accurate approximate formulas to estimate atmospheric loss enhancement due to the action of tidal forces on a "Hot Jupiter" and to calculate the critical temperature for the onset of "geometrical blow-off", which are valid for any physical values of the Roche lobe radial distance. Using these formulas, we found that the stellar tidal forces can enhance the hydrodynamic evaporation rate from TreS-1 and OGLE-TR-56b by about 2 fold, while for HD 209458b we found an enhancement of about 50%. For similar exoplanets which are closer to their host star than OGLE-TR-56b, the mass loss enhancement can be even larger. Moreover, we showed that the effect of the Roche lobe allows "Hot Jupiters" to reach blow-off conditions at temperatures which are less than expected due to the stellar X-ray and EUV heating.


Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Kulikov, Y.N.; Lammer, H.; Selsis, F.; Langmayr, D.; Jaritz, G.F.; Biernat, H.K.

[Text] / N. V. Erkaev [et al.] // Astrophys. J. Suppl. Ser. - 2005. - Vol. 157, Is. 2. - P396-401, DOI 10.1086/427904. - Cited References: 48 . - ISSN 0067-0049РУБ Astronomy & Astrophysics

Аннотация: During the past years, more than 130 giant planets were discovered in extrasolar planetary systems. Because of the fact that the orbital distances are very close to their host stars, these planets are embedded in a dense stellar wind, which can pick up planetary ions. We model the stellar wind interaction of the short-periodic exoplanets OGLE-TR-56b and HD 209458b at their orbital distances of approximate to 0.023 AU and approximate to 0.045 AU, by calculating the Alfven Mach number and the magnetosonic Mach number in the stellar wind plasma flow. We then analyze the different plasma interaction regimes around the planetary obstacles, which appear for different stellar wind parameters. Our study shows that the stellar wind plasma parameters like temperature, interplanetary magnetic field, particle density, and velocity near planetary obstacles at orbital distances closer than 0.1-0.2 AU have conditions such that no bow shocks evolve. Our study shows also that these close-in exoplanets are in a submagnetosonic regime comparable to the magnetospheric plasma interaction of the inner satellites of Jupiter and Saturn. Furthermore, we compare the results achieved for both exoplanets with the Jupiter-class exoplanet HD 28185b at its orbital distance of approximate to 1.03 AU. Finally, we also discuss the behavior of the stellar wind plasma flow close to the planetary obstacles of two highly eccentric gas giants, namely, HD 108147b and HD 162020b. Because of their eccentric orbits, these two exoplanets periodically experience both regimes with and without a bow shock. Finally, we simulate the neutral gas density of HD 209458b with a Monte Carlo model. By using the plasma parameters obtained in our study we calculate the ion production and loss rate of H+ with a test particle model. Our simulations yield H+ loss rates for HD 209458b or similar giant exoplanets in orders of about 10(8)-10(9) g s(-1). These ion loss rates are at least 1 order of magnitude lower than the observed loss rate of evaporating neutral H atoms. Our study indicates, that similar gas giants at larger orbital distances have lower ion loss rates. Thus, the dominating component of particle loss of short-periodic Jupiter-class exoplanets will be neutral hydrogen.


Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Penz, T.; Lammer, H.; Lichtenegger, H.I.M.; Biernat, H.K.; Wurz, P.; Griessmeier, J.M.; Weiss, W.W.

[Text] / M. Blanc, R. Kallenbach, N. V. Erkaev // Space Sci. Rev. - 2005. - Vol. 116: Workshop on Comparative Study of the Outer Planets before the Exploration of Saturn (JAN 12-14, 2004, Bern, SWITZERLAND), Is. 01.02.2013. - P227-298, DOI 10.1007/s11214-005-1958-y. - Cited References: 202 . - ISSN 0038-6308РУБ Astronomy & Astrophysics

Аннотация: This article proposes a short review of our present knowledge of solar system magnetospheres, with the purpose of placing the study of Saturn's inagnetosphere in the context of a comparative approach. We describe the diversity of solar system magnetospheres and the underlying causes of this diversity: nature and magnetization state of the planetary obstacle, presence or not of a dense atmosphere, rotation state of the planet, existence of a system of satellites, rings and neutral gas populations in orbit around the planet. We follow the "russian doll" hierarchy of solar system magnetospheres to briefly describe the different objects of this family: the heliosphere, which is the Sun's magnetosphere; the "elementary" magnetospheres of the inner planets, Earth and Mercury; the "complex" magnetospheres of the giant planets, dominated by planetary rotation and the presence of interacting objects within their magnetospheric cavities, some of which, like Ganymede, to or Titan, produce small intrinsic or induced magnetospheres inside the large one. We finally describe the main original features of Saturn's magnetosphere as we see them after the Voyager fly-bys and before the arrival of Cassini at Saturn, and list some of the key questions which Cassini will have to address during its four-year orbital tour.


Доп.точки доступа:
Blanc, M.; Kallenbach, R.; Erkaev, N.V.; Еркаев, Николай Васильевич

[Text] / K. G. Kislyakova [et al.] // Astron. Astrophys. - 2014. - Vol. 562. - Ст. A116, DOI 10.1051/0004-6361/201322933. - Cited References: 45. - K.G. Kislyakova, C.P. Johnstone, M.L. Khodachenko, H. Lammer, T. Luftinger and M. Gudel acknowledge the support by the FWF NFN project S116601-N16 "Pathways to Habitability: From Disks to Active Stars, Planets and Life", and the related EWE NFN subprojects, S116 604-N16 "Radiation & Wind Evolution from T Tauri Phase to ZAMS and Beyond". 5116 606-N16 "Magnetospheric Electrodynamics of Exoplanets", and S116607-N16 "Particle/Radiative Interactions with Upper Atmospheres of Planetary Bodies Under Extreme Stellar Conditions". T. Luftinger acknowledges also the support by the FWF project P19962-N16. K. G. Kislyakova, H. Lammer, and P. Odert thank also the Helmholtz Alliance project "Planetary Evolution and Life". P. Odert acknowledges support from the EWE project P22950-N16. The authors also acknowledge support from the EU FP7 project IMPEx (No.262863) and the EUROPLANET-RI projects, JRA3/EMDAF and the Na2 science WG5. N. V. Erkaev acknowledges support by the RFBR grant No 12-05-00152-a. Finally, the authors thank the International Space Science Institute (ISSI) in Bern, and the ISSI team "Characterizing stellar- and exoplanetary environments". This research was conducted using resources provided by the Swedish National Infrastructure for Computing (SNIC) at the High Performance Computing Center North (HPC2N). The authors thank also the anonymous referee for his useful comments. . - ISSN 0004-6361. - ISSN 1432-0746РУБ Astronomy & Astrophysics

Аннотация: Aims. We study the interactions between stellar winds and the extended hydrogen-dominated upper atmospheres of planets. We estimate the resulting escape of planetary pick-up ions from the five "super-Earths" in the compact Kepler-11 system and compare the escape rates with the efficiency of the thermal escape of neutral hydrogen atoms. Methods. Assuming the stellar wind of Kepler-11 is similar to the solar wind, we use a polytropic ID hydrodynamic wind model to estimate the wind properties at the planetary orbits. We apply a direct simulation Monte Carlo model to model the hydrogen coronae and the stellar wind plasma interaction around Kepler-11b-f within a realistic expected heating efficiency range of 15-40%. The same model is used to estimate the ion pick-up escape from the XUV heated and hydrodynamically extended upper atmospheres of Kepler-11b-f. From the interaction model, we study the influence of possible magnetic moments, calculate the charge exchange and photoionization production rates of planetary ions, and estimate the loss rates of pick-up H+ ions for all five planets. We compare the results between the five "super-Earths" and the thermal escape rates of the neutral planetary hydrogen atoms. Results. Our results show that a huge neutral hydrogen corona is formed around the planet for all Kepler-11b-f exoplanets. The non-symmetric form of the corona changes from planet to planet and is defined mostly by radiation pressure and gravitational effects. Non-thermal escape rates of pick-up ionized hydrogen atoms for Kepler-11 "super-Earths" vary between similar to.6.4x10(30) s(-1) and similar to 4.1 x10(31) s(-1), depending on the planet's orbital location and assumed heating efficiency. These values correspond to non-thermal mass loss rates of similar to 1.07 x 10(7) g s(-1) and similar to 6.8 x 10(2) g s(-1) respectively, which is a few percent of the thermal escape rates.

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ИВМ СО РАН

Доп.точки доступа:
Kislyakova, K.G.; Johnstone, C.P.; Odert, P.; Erkaev, N.V.; Еркаев, Николай Васильевич; Lammer, H.; Luftinger, T.; Holmstrom, M.; Khodachenko, M.L.; Guedel, M.; FWF NFN project [S116601-N16]; EWE NFN subprojects T Tauri Phase [S116 604-N16]; "Magnetospheric Electrodynamics of Exoplanets" [5116 606-N16]; "Particle/Radiative Interactions with Upper Atmospheres of Planetary Bodies Under Extreme Stellar Conditions" [S116607-N16]; FWF project [P19962-N16]; EWE project [P22950-N16]; EU [262863]; EUROPLANET-RI projects [JRA3/EMDAF, Na2 science WG5]; RFBR [12-05-00152-a]

[Text] / H. . Lammer [et al.] // Mon. Not. Roy. Astron. Soc. - 2014. - Vol. 439, Is. 4. - P. 3225-3238, DOI 10.1093/mnras/stu085. - Cited References: 75. - The authors acknowledge the support by the FWF NFN project S11601-N16 'Pathways to Habitability: From Disks to Active Stars, Planets and Life', and the related FWF NFN subprojects, S 116 02-N16 'Hydrodynamics in Young Star-Disk Systems', S116 604-N16 'Radiation & Wind Evolution from T Tauri Phase to ZAMS and Beyond', and S116607-N16 'Particle/Radiative Interactions with Upper Atmospheres of Planetary Bodies Under Extreme Stellar Conditions'. KGK, YNK, HL, and PO thank also the Helmholtz Alliance project 'Planetary Evolution and Life'. ML and PO acknowledge support from the FWF project P22950-N16. NVE acknowledges support by the RFBR grant no. 12-05-00152-a. Finally, the authors thank the International Space Science Institute (ISSI) in Bern, and the ISSI team 'Characterizing stellar-and exoplanetary environments'. . - ISSN 0035-8711. - ISSN 1365-2966РУБ Astronomy & Astrophysics

Аннотация: We investigate the origin and loss of captured hydrogen envelopes from protoplanets having masses in a range between 'sub-Earth'-like bodies of 0.1 M-circle plus and 'super-Earths' with 5 M-circle plus in the habitable zone at 1 au of a Sun-like G star, assuming that their rocky cores had formed before the nebula gas dissipated. We model the gravitational attraction and accumulation of nebula gas around a planet's core as a function of protoplanetary luminosity during accretion and calculate the resulting surface temperature by solving the hydrostatic structure equations for the protoplanetary nebula. Depending on nebular properties, such as the dust grain depletion factor, planetesimal accretion rates, and resulting luminosities, for planetary bodies of 0.1-1 M-circle plus we obtain hydrogen envelopes with masses between similar to 2.5 x 10(19) and 1.5 x 10(26) g. For 'super-Earths' with masses between 2 and 5 M-circle plus more massive hydrogen envelopes within the mass range of similar to 7.5 x 10(23)-1.5 x 10(28) g can be captured from the nebula. For studying the escape of these accumulated hydrogen-dominated protoatmospheres, we apply a hydrodynamic upper atmosphere model and calculate the loss rates due to the heating by the high soft-X-ray and extreme ultraviolet (XUV) flux of the young Sun/star. The results of our study indicate that under most nebula conditions 'sub-Earth' and Earth-mass planets can lose their captured hydrogen envelopes by thermal escape during the first similar to 100 Myr after the disc dissipated. However, if a nebula has a low dust depletion factor or low accretion rates resulting in low protoplanetary luminosities, it is possible that even protoplanets with Earth-mass cores may keep their hydrogen envelopes during their whole lifetime. In contrast to lower mass protoplanets, more massive 'super-Earths', which can accumulate a huge amount of nebula gas, lose only tiny fractions of their primordial hydrogen envelopes. Our results agree with the fact that Venus, Earth, and Mars are not surrounded by dense hydrogen envelopes, as well as with the recent discoveries of low density 'super-Earths' that most likely could not get rid of their dense protoatmospheres.

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ИВМ СО РАН

Доп.точки доступа:
Lammer, H.; Stokl, A.; Erkaev, N.V.; Еркаев, Николай Васильевич; Dorfi, E.A.; Odert, P.; Gudel, M.; Kulikov, Y.N.; Kislyakova, K.G.; Leitzinger, M.; FWF NFN [S11601-N16, S 116 02-N16, S116 604-N16, S116607-N16]; FWF [P22950-N16]; RFBR [12-05-00152-a]

/ I. F. Shaikhislamov [et al.] // Astrophys. J. - 2014. - Vol. 795, Is. 2, DOI 10.1088/0004-637X/795/2/132 . - ISSN 0004-637X
Аннотация: In the present series of papers we propose a consistent description of the mass loss process. To study in a comprehensive way the effects of the intrinsic magnetic field of a close-orbit giant exoplanet (a so-called hot Jupiter) on atmospheric material escape and the formation of a planetary inner magnetosphere, we start with a hydrodynamic model of an upper atmosphere expansion in this paper. While considering a simple hydrogen atmosphere model, we focus on the self-consistent inclusion of the effects of radiative heating and ionization of the atmospheric gas with its consequent expansion in the outer space. Primary attention is paid to an investigation of the role of the specific conditions at the inner and outer boundaries of the simulation domain, under which different regimes of material escape (free and restricted flow) are formed. A comparative study is performed of different processes, such as X-ray and ultraviolet (XUV) heating, material ionization and recombination, H+ 3 cooling, adiabatic and Lyα cooling, and Lyα reabsorption. We confirm the basic consistency of the outcomes of our modeling with the results of other hydrodynamic models of expanding planetary atmospheres. In particular, we determine that, under the typical conditions of an orbital distance of 0.05AU around a Sun-type star, a hot Jupiter plasma envelope may reach maximum temperatures up to ∼9000K with a hydrodynamic escape speed of ∼9 km s-1, resulting in mass loss rates of ∼ (4-7) · 1010 g s-1. In the range of the considered stellar-planetary parameters and XUV fluxes, that is close to the mass loss in the energy-limited case. The inclusion of planetary intrinsic magnetic fields in the model is a subject of the follow-up paper (Paper II).

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Institute of Computational Modelling, SB RASKrasnoyarsk, Russian Federation

Доп.точки доступа:
Shaikhislamov, I.F.; Khodachenko, M.L.; Sasunov, Y.L.; Lammer, H.; Kislyakova, K.G.; Erkaev, N.V.; Еркаев, Николай Васильевич

/ T. I. Maindl [et al.] // Astron. Astrophys. - 2015. - Vol. 574, DOI 10.1051/0004-6361/201424256 . - ISSN 0004-6361
Аннотация: Aims. We investigate the influence of impacts of large planetesimals and small planetary embryos on the early Martian surface on the hydrodynamic escape of an early steam atmosphere that is exposed to the high soft X-ray and extreme-ultraviolet (EUV) flux of the young Sun. Methods. Impact statistics in terms of number, masses, velocities, and angles of asteroid impacts onto early Mars are determined via n-body integrations. Based on these statistics, smoothed particle hydrodynamics (SPH) simulations result in estimates of energy transfer into the planetary surface material and the resulting surface heating. For the estimation of the atmospheric escape rates we applied a soft X-ray and EUV absorption model and a 1D upper atmosphere hydrodynamic model to a magma ocean-related catastrophically outgassed steam atmosphere with surface pressure values of 52 bar H2O and 11 bar CO2. Results. The estimated impact rates and energy deposition onto an early Martian surface can account for substantial heating. The energy influx and conversion rate into internal energy is probably sufficient to keep a shallow magma ocean liquid for an extended period of time. Higher surface temperatures keep the outgassed steam atmosphere longer in vapor form and therefore enhance its escape to space within ?0.6 Myr after its formation.

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Держатели документа:
Institute for Computational Modelling, Russian Academy of SciencesKrasnoyarsk 36, Russian Federation

Доп.точки доступа:
Maindl, T.I.; Dvorak, R.; Lammer, H.; Gudel, M.; Schafer, C.; Speith, R.; Odert, P.; Erkaev, N.V.; Еркаев, Николай Васильевич; Kislyakova, K.G.; Pilat-Lohinger, E.

/ A. Shevyrnogov, G. Vysotskaya, E. Shevyrnogov // Advances in Space Research. - 2004. - Vol. 33, Is. 7. - P. 1179-1183, DOI 10.1016/S0273-1177(03)00369-7 . - ISSN 0273-1177
Аннотация: The work presents the data on the spatial distribution of temperature anomalies in the Global Ocean, based on the long-term measurements with the AVHRR satellite equipment. It is noteworthy that such results can be only obtained by using long time series of satellite images. To obtain them by ship-borne methods is actually impossible. The proposed anomaly criterion is equal to a difference between minimum/maximum and average temperature, normed for the mean square deviation. The difference is calculated from the whole time series (with regard to a season). Based on this criterion, anomalies can be distinguished on the background of usual seasonal dynamics at various absolute values of deviations of the measured parameter. Besides, rare, single, fluctuations can be also revealed. Based on the proposed criterion, connected zones have been defined. These zones occur almost in every part of the Global Ocean. The data obtained have been analyzed in association with the CZCS (1978-1986) and SeaWiFS satellite images in order to compare them with the areas of anomalous dynamics of chlorophyll concentration and the regions quasistationary in the seasonal dynamics of chlorophyll. Anomalies in the temperature dynamics are of exceptional importance for the formation of climatic deviations; they affect the ocean-atmosphere interaction and reflect variations in the hydrological structure of the surface waters. The work presents a comparison with the dynamics of chlorophyll concentration distribution determined from the SeaWiFS data for the Atlantic Ocean. В© 2003 COSPAR. Published by Elsevier Ltd. All rights reserved.

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Shevyrnogov, A.; Vysotskaya, G.; Высоцкая, Галина Степановна; Shevyrnogov, E.

/ A. Shevyrnogov, G. Vysotskaya, E. Shevyrnogov // Advances in Space Research. - 2002. - Vol. 30, Is. 11. - P. 2535-2540, DOI 10.1016/S0273-1177(02)80332-5 . - ISSN 0273-1177
Аннотация: The new data on anomalies in seasonal dynamics of chlorophyll concentration in the ocean have altered the approach to the analysis of long-term trends of phytopigments in the surface layer of the ocean. Zones have been found in which at various times there was a many-fold increase in chlorophyll concentration versus its usual level. These changes are local in time and space. If anomalies in the long-term tendencies in the change of phytopigment surface distribution in the ocean are ignored in the analysis, the resulting picture will inadequately reflect the real processes. The work presents the results of the analysis of long-term trends of chlorophyll concentration on the basis of the CZCS satellite data in the Atlantic Ocean. The results are given as maps representing different variants of trends. The data obtained can be used to analyze the consequences of long-term changes of climate and changes in the interaction between the atmosphere and the ocean. В©2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.

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Shevyrnogov, A.; Vysotskaya, G.; Высоцкая, Галина Степановна; Shevyrnogov, E.

[Text] / N. V. Erkaev [et al.] // Mon. Not. Roy. Astron. Soc. - 2015. - Vol. 448, Is. 2. - P1916-1921, DOI 10.1093/mnras/stv130. - Cited References:28. - The authors acknowledge the support by the FWF NFN project S11601-N16 'Pathways to Habitability: From Disks to Active Stars, Planets and Life', and the related FWF NFN subproject, S11607-N16 'Particle/Radiative Interactions with Upper Atmospheres of Planetary Bodies Under Extreme Stellar Conditions'. PO acknowledges support from the FWF project P22950-N16. NVE acknowledges support by the RFBR grant no. 15-05-00879-a. Finally, the authors thank the International Space Science Institute (ISSI) in Bern, and the ISSI team 'Characterizing stellar-and exoplanetary environments'. . - ISSN 0035-8711. - ISSN 1365-2966РУБ Astronomy & Astrophysics

Аннотация: By considering martian-like planetary embryos inside the habitable zone of solar-like stars we study the behaviour of the hydrodynamic atmospheric escape of hydrogen for small values of the Jeans escape parameter beta < 3, near the base of the thermosphere, that is defined as a ratio of the gravitational and thermal energy. Our study is based on a 1D hydrodynamic upper atmosphere model that calculates the volume heating rate in a hydrogen-dominated thermosphere due to the absorption of the stellar soft X-ray and extreme ultraviolet (XUV) flux. In case of a monatomic gas, we find that when the beta value near the mesopause/homopause level exceeds a critical value of similar to 2.5, there exists a steady hydrodynamic solution with a smooth transition from subsonic to supersonic flow. For a fixed XUV flux, the escape rate of the upper atmosphere is an increasing function of the temperature at the lower boundary. Our model results indicate a crucial enhancement of the atmospheric escape rate, when the Jeans escape parameter beta decreases to this critical value. When beta becomes <= 2.5, there is no stationary hydrodynamic transition from subsonic to supersonic flow. This is the case of a fast non-stationary atmospheric expansion that results in extreme thermal atmospheric escape rates.

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Держатели документа:
Inst Computat Modelling SB RAS, Krasnoyarsk 660036, Russia.
Siberian Fed Univ, Krasnoyarsk 660041, Russia.
Austrian Acad Sci, Space Res Inst, A-8042 Graz, Austria.
Graz Univ, Inst Phys, A-8010 Graz, Austria.
Russian Acad Sci, Polar Geophys Inst, Murmansk 183010, Russia.
ИВМ СО РАН

Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Lammer, H.; Odert, P.; Kulikov, Yu. N.; Kislyakova, K.G.; FWF NFN [S11601-N16, S11607-N16]; FWF [P22950-N16]; RFBR [15-05-00879-a]

/ C. P. Johnstone [et al.] // Astrophys. J. Lett. - 2015. - Vol. 815, Is. 1, DOI 10.1088/2041-8205/815/1/L12 . - ISSN 2041-8205
Аннотация: Terrestrial planets formed within gaseous protoplanetary disks can accumulate significant hydrogen envelopes. The evolution of such an atmosphere due to XUV driven evaporation depends on the activity evolution of the host star, which itself depends sensitively on its rotational evolution, and therefore on its initial rotation rate. In this Letter, we derive an easily applicable method for calculating planetary atmosphere evaporation that combines models for a hydrostatic lower atmosphere and a hydrodynamic upper atmosphere. We show that the initial rotation rate of the central star is of critical importance for the evolution of planetary atmospheres and can determine if a planet keeps or loses its primordial hydrogen envelope. Our results highlight the need for a detailed treatment of stellar activity evolution when studying the evolution of planetary atmospheres. © 2015. The American Astronomical Society. All rights reserved.

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Держатели документа:
University of Vienna, Department of Astrophysics, Vienna, Austria
Space Research Institute, Austrian Academy of Sciences, Graz, Austria
Institute for Computational Modelling, Siberian Division, Russian Academy of Sciences, Krasnoyarsk, Russian Federation
Siberian Federal University, Krasnoyarsk, Russian Federation

Доп.точки доступа:
Johnstone, C. P.; Gudel, M.; Stokl, A. ; Lammer, H.; Tu, L.; Kislyakova, K. G.; Luftinger, T.; Odert, P.; Erkaev, N.V.; Еркаев, Николай Васильевич; Dorfi, E. A.
Свободных экз. нет

/ K. Yu. Slivka [et al.] // J. Geophys. Res. A. Space Phys. - 2015. - Vol. 120, Is. 11. - P9471-9483, DOI 10.1002/2015JA021250 . - ISSN 2169-9380
Аннотация: The magnetic barrier is a region which is formed in the course of the solar wind flow around the Earth's magnetosphere and is characterized by depleted plasma and an enhanced magnitude of the magnetic field. There is a general point of view that the magnetic barrier can persist only for the northward interplanetary magnetic field (IMF), whereas it is practically absent if the IMF is southward directed. We studied the presence of the magnetic barrier for low-shear (predominantly northward IMF) and high-shear (predominantly southward IMF) magnetopause conditions and analyzed 74 events of low-latitude dayside magnetopause crossings by the Time History of Events and Macroscale Interactions during Substorms satellites. We used the superposed epoch analysis to study variations of magnetic field and plasma parameters near the magnetopause. Results of Phan et al. (1994) that the magnetic barrier is well pronounced for low-shear magnetopauses and practically absent for high-shear events have been confirmed by our analysis. However, 5 from 49 high-shear events show clear signatures of a magnetic barrier. Hence, we conclude that the magnetic barrier is formed in the same manner for all direction of IMF but for high-shear events it is destroyed by reconnection much faster than it accumulates. Ratio of the events with and without magnetic barrier signatures (5/44) is approximately equal to the ratio of characteristic times of disruption due to reconnection (1-2 min) and the formation of a magnetic barrier (10 min). The reduction of the magnetic field due to reconnection can be used to estimate reconnection rate which turns out to be rather high of the order of 0.3 in 19 from 31 cases. ©2015. American Geophysical Union. All Rights Reserved.

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Держатели документа:
Earth Physics Department, Saint Petersburg State University, Saint Petersburg, Russian Federation
Institute of Computational Modelling SB RAS, Krasnoyarsk, Russian Federation
Department of Applied Mechanics, Polytechnic Institute, Siberian Federal University, Krasnoyarsk, Russian Federation
Space Research Institute, Austrian Academy of Sciences, Graz, Austria

Доп.точки доступа:
Slivka, K. Yu.; Semenov, V. S.; Erkaev, N.V.; Еркаев, Николай Васильевич; Dmitrieva, N. P.; Kubyshkin, I. V.; Lammer, H.

/ H. Lammer [et al.] // Mon. Not. R. Astron. Soc. Lett. - 2016. - Vol. 461, Is. 1. - PL62-L66, DOI 10.1093/mnrasl/slw095 . - ISSN 1745-3925
Аннотация: For the hot exoplanets CoRoT-24b and CoRoT-24c, observations have provided transit radii RT of 3.7 ± 0.4R? and 4.9 ± 0.5R?, and masses of ?5.7M? and 28 ± 11M?, respectively. We study their upper atmosphere structure and escape applying an hydrodynamic model. Assuming RT ? RPL, where RPL is the planetary radius at the pressure of 100 mbar, we obtained for CoRoT-24b unrealistically high thermally driven hydrodynamic escape rates. This is due to the planet's high temperature and low gravity, independent of the stellar EUV flux. Such high escape rates could last only for <100 Myr, while RPL shrinks till the escape rate becomes less than or equal to the maximum possible EUV-driven escape rate. For CoRoT-24b, RPL must be therefore located at ?1.9-2.2R? and high altitude hazes/clouds possibly extinct the light at RT. Our analysis constraints also the planet's mass to be 5-5.7M?. For CoRoT-24c, RPL and RT lie too close together to be distinguished in the same way. Similar differences between RPL and RT may be present also for other hot, low-density sub-Neptunes. © 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

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Держатели документа:
Space Research Institute, Austrian Academy of Sciences, Schmiedlstr. 6, Graz, Austria
Institute of Computational Modelling SB RAS, Krasnoyarsk, Russian Federation
Siberian Federal University, Krasnoyarsk, Russian Federation
Thuringer Landessternwarte Tautenburg, Sternwarte 5, Tautenburg, Germany
Institute for Astronomy, University of Vienna, Turkenschanzstrasse 17, Vienna, Austria

Доп.точки доступа:
Lammer, H.; Erkaev, N. V.; Fossati, L.; Juvan, I.; Odert, P.; Cubillos, P. E.; Guenther, E.; Kislyakova, K. G.; Johnstone, C. P.; Luftinger, T.; Gudel, M.

/ N. V. Erkaev [et al.] // Mon. Not. R. Astron. Soc. - 2016. - Vol. 460, Is. 2. - P1300-1309, DOI 10.1093/mnras/stw935 . - ISSN 0035-8711
Аннотация: We investigate the loss rates of the hydrogen atmospheres of terrestrial planets with a range of masses and orbital distances by assuming a stellar extreme ultraviolet (EUV) luminosity that is 100 times stronger than that of the current Sun. We apply a 1D upper atmosphere radiation absorption and hydrodynamic escape model that takes into account ionization, dissociation and recombination to calculate hydrogen mass-loss rates. We study the effects of the ionization, dissociation and recombination on the thermal mass-loss rates of hydrogen-dominated super-Earths and compare the results to those obtained by the energy-limited escape formula which is widely used for mass-loss evolution studies. Our results indicate that the energy-limited formula can to a great extent over- or underestimate the hydrogen mass-loss rates by amounts that depend on the stellar EUV flux and planetary parameters such as mass, size, effective temperature and EUV absorption radius. © 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

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Держатели документа:
Institute of Computational Modelling SB RAS, Krasnoyarsk, Russian Federation
Siberian Federal University, Krasnoyarsk, Russian Federation
Space Research Institute, Austrian Academy of Sciences, Schmiedlstr. 6, Graz, Austria
Institute for Astronomy, University of Vienna, Turkenschanzstrasse 17, Vienna, Austria

Доп.точки доступа:
Erkaev, N. V.; Lammer, H.; Odert, P.; Kislyakova, K. G.; Johnstone, C. P.; Gudel, M.; Khodachenko, M. L.

/ K. G. Kislyakova [et al.] // Mon. Not. R. Astron. Soc. - 2016. - Vol. 461, Is. 1. - P988-999, DOI 10.1093/mnras/stw1110 . - ISSN 0035-8711
Аннотация: We suggest an additional possible plasma source to explain part of the phenomena observed for the transiting hot Jupiters WASP-12b and HD 189733b in their ultraviolet (UV) light curves. In the proposed scenario, material outgasses from the molten surface of Trojan satellites on tadpole orbits near the Lagrange points L4 and L5. We show that the temperature at the orbital location of WASP-12b is high enough to melt the surface of rocky bodies and to form shallow lava oceans on them. In case of WASP-12b, this leads to the release of elements such as Mg and Ca, which are expected to surround the system. The predicted Mg and Ca outgassing rates from two Io-sizedWASP-12b Trojans are ?2.2 ? 1027 s-1 and ?2.2 ? 1026 s-1, respectively. Trojan outgassing can lead to the apparent lack of emission in Mg II h&k and Ca II H&K line cores of WASP-12. For HD 189733b, the mechanism is only marginally possible due to the lower temperature. This may be one of the reasons that could not explain the early ingress of HD 189733b observed in the far-UV C II doublet due to absence of carbon within elements outgassed by molten lava. We investigate the long-term stability region of WASP-12b and HD 189733b in case of planar and inclined motion of these satellites and show that unlike the classical exomoons orbiting the planet, Io-sized Trojans can be stable for the whole systems lifetime. © 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

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Держатели документа:
Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, Graz, Austria
University of Vienna, Department of Astrophysics, Turkenschanzstrasse 17, Vienna, Austria
IMCCE Observatoire de Paris, Univ. Lille 1, UPMC, 77 Avenue Denfert-Rochereau, Paris, France
Institute of Computational Modelling, Siberian Division of Russian Academy of Sciences, Akademgorodok, ICM SB RAS, Krasnoyarsk, Russian Federation
Siberian Federal University, Svobodnyy pr., 79, Krasnoyarsk, Russian Federation

Доп.точки доступа:
Kislyakova, K. G.; Pilat-Lohinger, E.; Funk, B.; Lammer, H.; Fossati, L.; Eggl, S.; Schwarz, R.; Boudjada, M. Y.; Erkaev, N. V.

[Текст] : статья / В. В. Двирный [и др.] // Информационные технологии и математическое моделирование в экономике, технике, экологии, образовании, педагогике и торговле. - 2016. - № 8. - С. 55-72
   Перевод заглавия: NUCLEAR POWER PLANT FOR SPACECRAFT

УДК	621.762.61

Аннотация: Основным источником энергоснабжения искусственных спутников Земли и космических аппаратов (КА) в настоящее время являются солнечные батареи (СБ). Однако они являются источниками тока с нелинейным и нестационарным внутренним сопротивлением. Кроме того, их характеристики в значительной степени изменяются в процессе эксплуатации: при выходе из тени Земли СБ генерируют максимальную энергию, которая с прогревом батареи уменьшается. А со временем СБ деградируют от воздействия ионизирующего излучения космического пространства. При этом также существуют сложности раскрытия и обеспечения требуемой ориентации. Наиболее высокоэффективным и стабильным источником энергии могут служить ядерные энергетические установки (ЯЭУ). Однако при этом важнейшим условием их применения является обеспечение радиационной безопасности при хранении в заводских условиях и транспортировке, для чего применяется транспортировочный контейнер. Представлена оригинальная конструкция контейнера для ЯЭУ КА, важнейшим элементом которого является металлорезиновый амортизатор, представляющий собой металлокомпозит, состоящий из металлической спирали, впрессованной в резину. Его назначение заключается в уменьшении амплитуды вибраций, что предотвращает контейнер от повреждений при транспортировке. С целью повышения физико-механических и эксплуатационных характеристик амортизатора в резину предварительно вводили нанопорошок углерода.
Nowadays the main power supply sources of artificial space satellites of the Earth and space vehicles (SV) are solar batteries (SB). However it is a source of power with nonlinear and unsteady internal resistance. Besides, its characteristics are to a great extent changed in operational process - SB generate maximum energy coming out of shadow of the Earth which decreases with battery warming-up. Further SB degrade by the influence of space ionizing radiation. At that there are also the difficulties with opening and supplying the demanded orientation. The most effective and stable source of energy canbe the nuclear installations (NI). However the most important condition for its use is a supplying of radiation safety by the storage at factory conditions and transportation wherefore the transporting container is used. The original construction of the container for NI SV, the most important element of which is a metallic rubber shock-absorber that is a metallic composite consisted of metallic spiral pressed into rubber is presented in the article. Its destination is in a decreasing of a vibration amplitude that prevents container from damages during transportation. The nanopowder of carbon was previously introduced into rubber for increasing the physical-mechanical and operational characteristics of shock-absorber.

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Держатели документа:
АО «Информационные спутниковые системы» имени академика М. Ф. Решетнева»
Институт вычислительного моделирования СО РАН
Конструкторское бюро «Арсенал» имени М. Ф. Фрунзе
Сибирская пожарно-спасательная академия ГПС МЧС России
Сибирский государственный аэрокосмический университет имени академика М. Ф. Решетнева

Доп.точки доступа:
Двирный, В.В.; Dvirnyi V.V.; Крушенко, Генрих Гаврилович; Krushenko G.G.; Елфимова, М.В.; Elfimova M.V.; Двирный, Г.В.; Голованова, В.В.; Golovanova V.V.

/ P. Cubillos [et al.] // Mon. Not. Roy. Astron. Soc. - 2017. - Vol. 466, Is. 2. - P1868-1879, DOI 10.1093/mnras/stw3103. - Cited References:107. - We thank contributors to SCIPY, MATPLOTLIB (Hunter 2007), the PYTHON programming language, and contributors to the free and open-source community. We thank the anonymous referee for comments that significantly improved the quality of the paper. This research has made use of the Exoplanet Orbit Database and the Exoplanet Data Explorer at exoplanets.org and the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. We acknowledge the Austrian Forschungsforderungsgesellschaft FFG projects 'RASEN' P847963 and 'TAPAS4CHEOPS' P853993, the Austrian Science Fund (FWF) National Research Network projects S11607-N16 and S11604-N16, and the FWF project P27256-N27. NVE acknowledges support by the Russian Foundation for Basic Research grant no. 15-05-00879-a and no. 16-52-14006 ANF-a. . - ISSN 0035-8711. - ISSN 1365-2966РУБ Astronomy & Astrophysics

Аннотация: We present a uniform analysis of the atmospheric escape rate of Neptune-like planets with estimated radius and mass (restricted to M-p < 30M(circle plus)). For each planet, we compute the restricted Jeans escape parameter, Lambda, for a hydrogen atom evaluated at the planetary mass, radius, and equilibrium temperature. Values of Lambda less than or similar to 20 suggest extremely high mass-loss rates. We identify 27 planets (out of 167) that are simultaneously consistent with hydrogen-dominated atmospheres and are expected to exhibit extreme mass-loss rates. We further estimate the mass-loss rates (L-hy) of these planets with tailored atmospheric hydrodynamic models. We compare L-hy to the energy-limited (maximum-possible high-energy driven) mass-loss rates. We confirm that 25 planets (15 per cent of the sample) exhibit extremely high mass-loss rates (L-hy > 0.1M(circle plus) Gyr(-1)), well in excess of the energy-limited mass-loss rates. This constitutes a contradiction, since the hydrogen envelopes cannot be retained given the high mass-loss rates. We hypothesize that these planets are not truly under such high mass-loss rates. Instead, either hydrodynamic models overestimate the mass-loss rates, transit-timing-variation measurements underestimate the planetary masses, optical transit observations overestimate the planetary radii (due to high-altitude clouds), or Neptunes have consistently higher albedos than Jupiter planets. We conclude that at least one of these established estimations/ techniques is consistently producing biased values for Neptune planets. Such an important fraction of exoplanets with misinterpreted parameters can significantly bias our view of populations studies, like the observed mass-radius distribution of exoplanets for example.

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Держатели документа:
Austrian Acad Sci, Space Res Inst, Schmiedlstr 6, A-8042 Graz, Austria.
SB RAS, Krasnoyarsk Sci Ctr, Fed Res Ctr, Inst Computat Modelling, Krasnoyarsk 660036, Russia.
Univ Vienna, Dept Astrophys, Turkenschanzstr 17, A-1180 Vienna, Austria.
Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.

Доп.точки доступа:
Cubillos, Patricio; Erkaev, N.V.; Еркаев, Николай Васильевич; Juvan, Ines; Fossati, Luca; Johnstone, Colin P.; Lammer, Helmut; Lendl, Monika; Odert, Petra; Kislyakova, Kristina G.; Austrian Forschungsforderungsgesellschaft FFG [P847963, P853993]; Austrian Science Fund (FWF) National Research Network projects [S11607-N16, S11604-N16]; FWF [P27256-N27]; Russian Foundation for Basic Research [15-05-00879-a, 16-52-14006 ANF-a]

/ L. Fossati [et al.] // Astron. Astrophys. - 2017. - Vol. 598. - Ст. A90, DOI 10.1051/0004-6361/201629716. - Cited References:48. - We acknowledge the Austrian Forschungsforderungsgesellschaft FFG projects "RASEN" P847963 and "TAPAS4CHEOPS" P853993, the Austrian Science Fund (FWF) NFN project S11607-N16, and the FWF project P27256-N27. N.V.E. acknowledges support by the RFBR grant Nos. 15-05- 00879-a and 16-52-14006 ANF_a. We thank the anonymous referee for the comments that led to a considerable improvement of the manuscript. . - ISSN 1432-0746РУБ Astronomy & Astrophysics

Аннотация: Stimulated by the discovery of a number of close-in low-density planets, we generalise the Jeans escape parameter taking hydrodynamic and Roche lobe effects into account. We furthermore define Lambda as the value of the Jeans escape parameter calculated at the observed planetary radius and mass for the planet's equilibrium temperature and considering atomic hydrogen, independently of the atmospheric temperature profile. We consider 5 and 10 M-circle plus planets with an equilibrium temperature of 500 and 1000 K, orbiting early G-, K-, and M-type stars. Assuming a clear atmosphere and by comparing escape rates obtained from the energy-limited formula, which only accounts for the heating induced by the absorption of the high-energy stellar radiation, and from a hydrodynamic atmosphere code, which also accounts for the bolometric heating, we find that planets whose Lambda is smaller than 15-35 lie in the "boil-off" regime, where the escape is driven by the atmospheric thermal energy and low planetary gravity. We find that the atmosphere of hot ( i.e. T-eq >= 1000 K) low-mass (M-pl <= 5 M-circle plus) planets with Lambda < 15-35 shrinks to smaller radii so that their Lambda evolves to values higher than 15-35, hence out of the boil-off regime, in less than approximate to 500 Myr. Because of their small Roche lobe radius, we find the same result also for hot (i.e. T-eq >= 1000 K) higher mass (M-pl <= 10 M-circle plus) planets with Lambda < 15-35, when they orbit M-dwarfs. For old, hydrogen-dominated planets in this range of parameters, Lambda should therefore be >= 15-35, which provides a strong constraint on the planetary minimum mass and maximum radius and can be used to predict the presence of aerosols and/or constrain planetary masses, for example.

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Держатели документа:
Austrian Acad Sci, Space Res Inst, Schmiedlstr 6, A-8042 Graz, Austria.
SB RAS, Krasnoyarsk Sci Ctr, Fed Res Ctr, Inst Computat Modelling, Krasnoyarsk 36, Russia.
Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
Karl Franzens Univ Graz, Inst Geophys Astrophys & Meteorol, Univ Pl 5, A-8010 Graz, Austria.

Доп.точки доступа:
Fossati, L.; Erkaev, N.V.; Еркаев, Николай Васильевич; Lammer, H.; Cubillos, P. E.; Odert, P.; Juvan, I.; Kislyakova, K. G.; Lendl, M.; Kubyshkina, D.; Bauer, S. J.; Austrian Forschungsforderungsgesellschaft FFG projects ["RASEN" P847963, "TAPAS4CHEOPS" P853993]; Austrian Science Fund (FWF) NFN project [S11607-N16]; FWF project [P27256-N27]; RFBR grant [15-05- 00879-a, 16-52-14006 ANF_a]