Труды сотрудников ИВМ СО РАН

/ K. G. Kislyakova [et al.] // Astrobiology. - 2013. - Vol. 13, Is. 11. - P1030-1048, DOI 10.1089/ast.2012.0958 . - ISSN 1531-1074
Аннотация: We studied the interactions between the stellar wind plasma flow of a typical M star, such as GJ 436, and the hydrogen-rich upper atmosphere of an Earth-like planet and a "super-Earth" with a radius of 2 R Earth and a mass of 10 MEarth, located within the habitable zone at ∼0.24 AU. We investigated the formation of extended atomic hydrogen coronae under the influences of the stellar XUV flux (soft X-rays and EUV), stellar wind density and velocity, shape of a planetary obstacle (e.g., magnetosphere, ionopause), and the loss of planetary pickup ions on the evolution of hydrogen-dominated upper atmospheres. Stellar XUV fluxes that are 1, 10, 50, and 100 times higher compared to that of the present-day Sun were considered, and the formation of high-energy neutral hydrogen clouds around the planets due to the charge-exchange reaction under various stellar conditions was modeled. Charge-exchange between stellar wind protons with planetary hydrogen atoms, and photoionization, lead to the production of initially cold ions of planetary origin. We found that the ion production rates for the studied planets can vary over a wide range, from ∼1.0×1025 s-1 to ∼5.3×1030 s-1, depending on the stellar wind conditions and the assumed XUV exposure of the upper atmosphere. Our findings indicate that most likely the majority of these planetary ions are picked up by the stellar wind and lost from the planet. Finally, we estimated the long-time nonthermal ion pickup escape for the studied planets and compared them with the thermal escape. According to our estimates, nonthermal escape of picked-up ionized hydrogen atoms over a planet's lifetime within the habitable zone of an M dwarf varies between ∼0.4 Earth ocean equivalent amounts of hydrogen (EOH) to <3 EOH and usually is several times smaller in comparison to the thermal atmospheric escape rates. © 2013 Mary Ann Liebert, Inc.

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Держатели документа:
Space Research Institute, Austrian Academy of Sciences, Schmiedlstr. 6, A-8042 Graz, Austria
Institute of Physics, University of Graz, Graz, Austria
Swedish Institute of Space Physics, Kiruna, Sweden
Institute of Computational Modelling, Siberian Division of the Russian Academy of Sciences, Krasnoyarsk, Russian Federation
SINP, Moscow State University, Moscow, Russian Federation
Polar Geophysical Institute (PGI), Russian Academy of Sciences, Murmansk, Russian Federation
Institute of Astrophysics, University of Vienna, Austria
ИВМ СО РАН

Доп.точки доступа:
Kislyakova, K.G.; Lammer, H.; Holmstrom, M.; Panchenko, M.; Odert, P.; Erkaev, N.V.; Еркаев, Николай Васильевич; Leitzinger, M.; Khodachenko, M.L.; Kulikov, Y.N.; Gudel, M.; Hanslmeier, A.

[Text] / C. J. Farrugia [et al.] // J. Geophys. Res-Space Phys. - 2008. - Vol. 113. - Ст. A00B01, DOI 10.1029/2007JA012953. - Cited References: 38 . - ISSN 0148-0227РУБ Astronomy & Astrophysics

Аннотация: We identify a planar, pressure-balanced structure bounded by sharp changes in the dynamic pressure plastered against the front boundary of the magnetic cloud which passed Earth on 20 November 2003. The front boundary of the magnetic cloud (MC) is particularly well-defined in this case, being located where the He(++)/H(+) number density ratio jumps from 4 to 10% for the first time and the proton plasma beta decreases sharply from similar to 1 to similar to 0.001. The feature, estimated to have a length scale similar to 50 RE in the Sun-Earth direction, bears close resemblance to a slow mode transition region in that the magnetic pressure decreases, the plasma pressure increases, and their temporal variations are anticorrelated. Using a 2-D MHD simulation, we hypothesize that a pressure-balanced structure was encountered by the MC en route to Earth. Our calculations reproduce qualitatively the major features of the observations. Using a simplified geometry suggested by the observations, we find that the lateral deflection speed of the plasma is less than the lateral expansion speed of the MC. We infer that the structure traversed the MC sheath in similar to 20 h, consistent with its crossing of the MC's shock at 0.6-0.7 AU. The finding is consistent with the recent paradigm according to which solar wind plasma and magnetic field tend to pile up in front of interplanetary ejecta because the expansion of the ejecta hinders the shocked solar wind plasma from deflecting effectively around the object. Also, the inferred "age'' of the layer contiguous to the surface of the MC, the earliest relic of its passage through the inner heliosphere, is in agreement with general estimates.


Доп.точки доступа:
Farrugia, C.J.; Erkaev, N.V.; Еркаев, Николай Васильевич; Taubenschuss, U.; Shaidurov, V.A.; Smith, C.W.; Biernat, H.K.

[Text] / T. Penza [et al.] // Planet Space Sci. - 2008. - Vol. 56, Is. 9. - P1260-1272, DOI 10.1016/j.pss.2008.04.005. - Cited References: 53 . - ISSN 0032-0633РУБ Astronomy & Astrophysics

Аннотация: We investigate the efficiency of the atmospheric mass loss due to hydrodynamic blow-off over the lifetime of the exoplanet HD209458b by studying numerically its hydrogen wind for host star X-ray and EUV (XUV) fluxes between 1 and 100 times that of the present Sun. We apply a time-dependent numerical algorithm which is able to solve the system of hydrodynamic equations straight through the transonic point of the flow including Roche lobe effects. The mass loss rates are calculated as functions of the absorbed energy in the thermosphere. Depending on the heating efficiency for a hydrogen-rich thermosphere the maximum temperature obtained in our study at 1.5R(p1) by neglecting IR cooling is about 5000-10,000 K for heating efficiencies of 10% and 60%, respectively. We find that the upper atmosphere of HD209458b experiences hydrodynamic blow-off even at such low temperatures if one does not neglect gravitational effects caused by the proximity of the planet to its Roche lobe boundary. Depending on the heating efficiency, we find from the solution of the hydrodynamic equations of mass, momentum, and energy balance that energy-limited mass loss rate estimations overestimate the realistic mass loss rate at present time for HD209458b by several times. Using the maximum heating efficiency for hydrogen-rich atmospheres of 60% we find that HD209458b may experience an atmospheric mass loss rate at present time of about 3.5 x 10(10) g s(-1). The mass loss rate evolves to higher values for higher XUV fluxes expected during the early period of the planet's host star evolution, reaching values of several times 10(12) gs(-1). The integrated mass loss is found to be between 1.8% and 4.4% of the present mass of HD209458b. We found that the influence of the stellar tidal forces on atmospheric loss (the Roche lobe effect) is not significant at 0.045 AU. For a similar exoplanet, but at closer orbital distances <= 0.02 AU, the combined effect of the Roche lobe and the high XUV radiation result in much higher thermal loss rates of about 2.6 x 10(11) g s(-1) and even more for early stages. This leads to a total loss over 4 Gyr of 27.5% of the planetary mass. (c) 2008 Elsevier Ltd. All rights reserved.

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Доп.точки доступа:
Penza, T.; Erkaev, N.V.; Еркаев, Николай Васильевич; Kulikov, Y.N.; Langmayr, D.; Lammer, H.; Micela, G.; Cecchi-Pestellini, C.; Biernat, H.K.; Selsis, F.; Barge, P.; Deleuil, M.; Leger, A.

[Text] / M. L. Khodachenko [et al.] // Planet Space Sci. - 2007. - Vol. 55: Symposium on Exoplanets and Planetary Formation (APR 25-30, 2004, Nice, FRANCE), Is. 5. - P631-642, DOI 10.1016/j.pss.2006.07.010. - Cited References: 63 . - ISSN 0032-0633РУБ Astronomy & Astrophysics

Аннотация: Atmospheric erosion due to CME-caused ion pick-up is investigated here for the first time for short periodic gas giants (so-called "Hot Jupiters") orbiting close to a star, To study the effect of encountering CMEs produced on the inagnetospheres and atmospheres of "Hot Jupiters" we model possible interaction of dense CME plasma with the exoplanet HD209458b (r(pl) = 1.43r(Jup) M(pl) = 0.69 M(jup)), which orbits a 4.0-5.0 Gyr old Sun-like star at a distance of about 0.045 AU. A numerical hydrodynamic model is applied for calculation of the upper atmospheric density and the hydrogen wind of HD209458b Lis a function of planetocentric distance. Taking into account the similarity of HD209458b's host star to Our Sun we use for the study of the ion production and loss rate of H(+) ions the solar CME plasma parameters and apply a numerical test particle model. Tidal-locking of short periodic exoplanets closely located to their host stars should result in weaker intrinsic planetary magnetic moments, as compared to those of the fast rotating Jupiter type planets at much larger orbits. It is shown that in this case the encountering CME plasma can compress the magnetospheric stand-off distance of short periodic "Hot Jupiters" down to the heights Lit which the ionization and pick-LIP of the planetary neutral atmosphere by the CME plasma flow take place. Assuming for the host star of HD209458b the same CME occurrence rate Lis on the Suit, we estimate possible total mass loss rates of HD2094581b due to its collisions with CMEs over the planet lifetime. It has been found that Under different estimations of the value of a planetary magnetic moment, HD209458b Could have lost over its lifetime the mass from 0-2 up to several times of its present mass M(pl). (c) 2006 Elsevier Ltd. All rights reserved.


Доп.точки доступа:
Khodachenko, M.L.; Lammer, H.; Lichtenegger, H.I.M.; Langmayr, D.; Erkaev, N.V.; Еркаев, Николай Васильевич; Griessmeier, J.M.; Leitner, M.; Penz, T.; Biernat, H.K.; Motschmann, U.; Rucker, H.O.

[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] / H. K. Biernat [et al.] // COMPARATIVE RECONNECTION STUDIES AT THE SUN AND IN PLANETARY MAGNETOSPHERES. Ser. ADVANCES IN SPACE RESEARCH : PERGAMON-ELSEVIER SCIENCE LTD, 2002. - Vol. 29: D0 1-E3 1 Symposium of COSPAR Scientific Commission D held at the 33rd COSPAR Scientific Assmbly (JUL, 2000, WARSAW, POLAND), Is. 7. - P1069-1074, DOI 10.1016/S0273-1177(02)00023-6. - Cited References: 12 . - ISBN 0273-1177РУБ Engineering, Aerospace + Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences

Аннотация: Many observations show a difference between the pressure parallel and perpendicular to the magnetic field. Thus it is reasonable to study the Petschek reconnection mechanism for the set of equations allowing for pressure anisotropy. We study the simplest case of so-called Petschek shocks, where the Alfven discontinuity and the slow shock degenerate to one discontinuity. More specifically, we consider switch-off shocks, where the magnetic field on the downstream side vanishes in lowest order, so that the plasma is isotropic on that side. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.


Доп.точки доступа:
Biernat, H.K.; Muhlbachler, S.; Semenov, V.S.; Erkaev, N.V.; Еркаев, Николай Васильевич; Vogl, D.F.; Ivanova, V.V.

[Text] / S. Muhlbachler [et al.] // COMPARATIVE RECONNECTION STUDIES AT THE SUN AND IN PLANETARY MAGNETOSPHERES. Ser. ADVANCES IN SPACE RESEARCH : PERGAMON-ELSEVIER SCIENCE LTD, 2002. - Vol. 29: D0 1-E3 1 Symposium of COSPAR Scientific Commission D held at the 33rd COSPAR Scientific Assmbly (JUL, 2000, WARSAW, POLAND), Is. 7. - P1113-1118, DOI 10.1016/S0273-1177(02)00033-9. - Cited References: 14 . - ISBN 0273-1177РУБ Engineering, Aerospace + Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences

Аннотация: Magnetic reconnection is a process which allows topological different magnetic fields to interconnect. Thus, in magnetospheric context, reconnection is strongly associated with substorm phenomena. Because many observations show a difference between the pressure parallel and perpendicular to the magnetic field, it is reasonable to study the reconnection mechanism for the set of equations, involving a pressure tensor. Existing theoretical work for isotropic weak reconnection is extended for anisotropic theory. In particular, the reconnection associated discontinuities as the Alfven discontinuity, the slow shock, and the contact discontinuity are generalized for anisotropic pressure. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.


Доп.точки доступа:
Muhlbachler, S.; Biernat, H.K.; Semenov, V.S.; Farrugia, C.J.; Vogl, D.F.; Erkaev, N.V.; Еркаев, Николай Васильевич

[Text] / H. K. Biernat, N. V. Erkaev, C. J. Farrugia // J. Geophys. Res-Space Phys. - 1999. - Vol. 104, Is. A6. - P12617-12626, DOI 10.1029/1999JA900032. - Cited References: 37 . - ISSN 0148-0227РУБ Astronomy & Astrophysics

Аннотация: We describe the "magnetic string" approach to integrating the dissipationless magnetohydrodynamic (MHD) equations for flow around planetary obstacles and apply it to some aspects of the flow in the magnetosheath of Venus. Our method has both analytical and numerical components and is particularly suited to study the structure of the magnetic barrier (depletion layer). We do not include ion pickup processes and thus discuss only the contribution to the structure of the Venus magnetosheath made by the flow of the shocked solar wind. We work with an interplanetary magnetic field which is directed orthogonal to the solar wind bulk velocity. Magnetic forces on the flow are strongly dependent on the Alfven Mach number upstream of the bow shock, and one aim of this work is to study the dependence of field and flow quantities in the Venus magnetosheath on this parameter, thus allowing further future comparisons with data under a variety of interplanetary conditions. A second aim is to compare our MHD model results to a? synopsis of observations made by the Pioneer Venus Orbiter. As one main conclusion, we show that this method leads, in principle, to a standoff bow shock position in good agreement with observations. We find, namely, that for a low but reasonable Alfven Mach number, our MHD-modeled magnetosheath is only similar to 3.6% thinner in the Sun-Venus direction than that given by observations. Our method is complementary to three-dimensional, global MHD simulations of the solar wind-Venus interaction and offers versatility to modeling other aspects of the complicated interaction of the solar wind with Venus.


Доп.точки доступа:
Biernat, H.K.; Erkaev, N.V.; Еркаев, Николай Васильевич; Farrugia, C.J.

[Text] / N. V. Erkaev, V. S. Semenov, H. K. Biernat // COMPARATIVE RECONNECTION STUDIES AT THE SUN AND IN PLANETARY MAGNETOSPHERES. Ser. ADVANCES IN SPACE RESEARCH : PERGAMON-ELSEVIER SCIENCE LTD, 2002. - Vol. 29: D0 1-E3 1 Symposium of COSPAR Scientific Commission D held at the 33rd COSPAR Scientific Assmbly (JUL, 2000, WARSAW, POLAND), Is. 7. - P1075-1080, DOI 10.1016/S0273-1177(02)00024-8. - Cited References: 15 . - ISBN 0273-1177РУБ Engineering, Aerospace + Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences

Аннотация: Using a two-dimensional, incompressible magnetohydrodynamic (MHD) model, we study unsteady reconnection of antiparallel magnetic fields in the symmetric case. The magnetic reconnection process is initiated by variation of a local resistivity assumed to be a given function of time and spatial coordinates. The diffusion region of reconnection is treated as a thin boundary layer where the perpendicular components of magnetic field and velocity are much smaller than the components of these quantities along the layer. The unsteady MHD equations are solved by a two-step finite difference numerical scheme with an implicit approximation of the magnetic diffusion terms in a uniform right angle grid. In the numerical study, we use the initial conditions related to a uniform current layer without any motion of the plasma. The time-dependent reconnection process is characterized by the following important parameters: A timescale of the local resistivity, a length scale of the local resistivity, a local Reynolds number determined for the maximum resistivity and the length scale of the diffusion region. The numerical results show that the Petschek type reconnection is realized for the sufficiently small length scale and large time scale of the local resistivity, and a moderate local Reynolds number. Using unsteady numerical MHD solution obtained for the diffusion region, we determine the reconnection rate as a function of time by matching of the outer Petschek solution and the internal diffusion region solution. (C) 2002 COSPAR, Published by Elsevier Science Ltd. All rights reserved.


Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Semenov, V.S.; Biernat, H.K.

[Text] / C. J. Farrugia [et al.] // Adv. Space Res. - 2009. - Vol. 44, Is. 11. - P1288-1294, DOI 10.1016/j.asr.2009.07.003. - Cited References: 29. - Work supported by Project P20145-N16 and by I.2/04 Osterreichische Austauschdient. . - ISSN 0273-1177РУБ Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences

Аннотация: Using a serendipitous configuration of the ACE and Wind spacecraft, we monitor the response of the distant geomagnetic tail (similar to-220 R(E)) to an abrupt, approx. fivefold pressure drop (from similar to 19.0 to similar to 3.5 nPa) at the front boundary of a magnetic cloud (MC) on November 20, 2003. The interplanetary data are from ACE in orbit around the L1 point. The far-tail observations are from Wind, which was nominally in the magnetosheath, separated from the Sun-Earth line by similar to 40 R(E). The magnetic field in the innermost sheath region of the MC had a large B(y) (similar to 30 nT) and substantial and variable flows lateral to the Sun-Earth line. There was also a significant northward field (similar to 35 nT), unique in the vicinity of this MC. These extreme values are reached in a filament forming the earliest relic of material accreted by the MC en route to Earth. The effects resulting from these on the far geomagnetic tail are: (1) expansion, (2) tail twisting, and (3) tail tilting. These extreme conditions were in part responsible for a crossing by Wind of a neutral sheet which is tilted by similar to 85 degrees to the ecliptic. Further, Wind made two successive excursions deep into the geomagnetic tail, in the first of which a tailward flow burst of similar to 1200 km/s was observed. The dayside part of the interaction of the sudden and large dynamic pressure drop with the bow shock is studied with a local 3D MHD simulation. This work is a contribution to the area ICME/MC-sheaths-magnetosheath interactions. (C) 2009 COSPAR. Published by Elsevier Ltd. All rights reserved.


Доп.точки доступа:
Farrugia, C.J.; Erkaev, N.V.; Еркаев, Николай Васильевич; Maynard, N.C.; Richardson, I.G.; Sandholt, P.E.; Langmayr, D.; Ogilvie, K.W.; Szabo, A.; Taubenschuss, U.; Torbert, R.B.; Biernat, H.K.; NASA [NNG05GG25G, NNX08AD11G]; RFBR [07-05-00135]; RAS [2.16, 16.3]; Osterreichische Austauschdient [I.2/04]; [P20145-N16]

[Text] / N. V. Erkaev [et al.] // Planet Space Sci. - 2014. - Vol. 98. - P. 106-119, DOI 10.1016/j.pss.2013.09.008. - Cited References: 94. - P. Odert, H. Lammer, K. G. Kislyakova and Yu. N. Kulikov acknowledge support from the Helmholtz Alliance project "Planetary Evolution and Life". E. Dorfi, M. Gudel, K. G. Kislyakova, H. Lammer, A. Stokl and E. A. Dorfi acknowledge the Austrian Science Fund (FWF) for supporting this study via the FWF NFN project S116 "Pathways to Habitability: From Disks to Active Stars, Planets and Life", and the related FWF NFN subprojects, S 116 02-N1 "Hydrodynamics in Young Star-Disk Systems", S116 604-N16 "Radiation & Wind Evolution from T Tauri Phase to ZAMS and Beyond", and S11607-N16 "Particle/Radiative Interactions with Upper Atmospheres of Planetary Bodies Under Extreme Stellar Conditions". M. Leitzinger and P. Odert also acknowledge the support from the FWF project P22950-N16. N. V. Erkaev acknowledges support by the RFBR Grant no 12-05-00152-a. Finally, H. Lammer thanks M. lkoma from the Department of Earth and Planetary Science, of the University of Tokyo, Japan, for discussions related to the accumulation of nebular-based hydrogen envelopes around Mars-mass bodies. Finally the authors thank an anonymous referee for the interesting and important suggestions and recommendations that helped to improve the results of our study. . - ISSN 0032-0633РУБ Astronomy & Astrophysics

Аннотация: Latest research in planet formation indicates that Mars formed within a few million years (Myr) and remained as a planetary embryo that never grew to a more massive planet. It can also be expected from dynamical models that most of Mars' building blocks consisted of material that formed in orbital locations just beyond the ice line which could have contained similar to 0.1-0.2 wt.% of H2O. By using these constraints, we estimate the nebula-captured and catastrophically outgassed volatile contents during the solidification of Mars' magma ocean and apply a hydrodynamic upper atmosphere model for the study of the soft X-ray and extreme ultraviolet (XUV) driven thermal escape of the martian protoatmosphere during the early active epoch of the young Sun. The amount of gas that has been captured from the protoplanetary disk into the planetary atmosphere is calculated by solving the hydrostatic structure equations in the protoplanetary nebula. Depending on nebular properties such as the dust grain depletion factor, planetesimal accretion rates and luminosities, hydrogen envelopes with masses >= 3 x 10(19) g to <= 6.5 x 10(22) g could have been captured from the nebula around early Mars. Depending on the before mentioned parameters, due to the planets low gravity and a solar XUV flux that was similar to 100 times stronger compared to the present value, our results indicate that early Mars would have lost its nebular captured hydrogen envelope after the nebula gas evaporated, during a fast period of similar to 0.1-7.5 Myr. After the solidification of early Mars' magma ocean, catastrophically outgassed volatiles with the amount of similar to 50-250 bar H2O and similar to 10-55 bar CO2 could have been lost during similar to 0.4-12 Myr, if the impact related energy flux of large planetesimals and small embryos to the planet's surface lasted long enough, that the steam atmosphere could have been prevented from condensing. If this was not the case, then our results suggest that the timescales for H2O condensation and ocean formation may have been shorter compared to the atmosphere evaporation timescale, so that one can speculate that sporadically periods, where some amount of liquid water may have been present on the planet's surface. However, depending on the amount of the outgassed volatiles, because of impacts and the high XUV-driven atmospheric escape rates, such sporadically wet surface conditions may have also not lasted much longer than similar to 0.4-12 Myr. After the loss of the captured hydrogen envelope and outgassed volatiles during the first 100 Myr period of the young Sun, a warmer and probably wetter period may have evolved by a combination of volcanic outgassing and impact delivered volatiles similar to 4.0 +/- 0.2 Gyr ago, when the solar XUV flux decreased to values that have been <10 times that of today's Sun. (C) 2013 Elsevier Ltd. All rights reserved.

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Держатели документа:
ИВМ СО РАН

Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Lammer, H.; Elkins-Tanton, L.T.; Stokl, A.; Odert, P.; Marcq, E.; Dorfi, E.A.; Kislyakova, K.G.; Kulikov, Y.N.; Leitzinger, M.; Gudel, M.; Helmholtz Alliance project "Planetary Evolution and Life"; Austrian Science Fund (FWF); Austrian Science Fund (FWF) via the FWF NFN project [S116]; FWF NFN subprojects [S 116 02-N1, S116 604-N16, S11607-N16]; FWF project [P22950-N16]; 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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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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Держатели документа:
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.

[Текст] : статья / Д. Л. Чубаров, В. А. Кочнев // Глубинное строение, геодинамика, тепловое поле Земли, интерпретация геофизических полей : материалы конференции. - Екатеринбург : Институт геофизики им. Ю.П. Булашевича УрО РАН, 2015. - С. 363-367
   Перевод заглавия: Calculation an analysis of Moon's and Sun's tidal forces, acting on unit mass body

УДК	550.34.013.4

Аннотация: В данной статье описывается методика расчета и анализ модели влияния приливных сил Луны и Солнца на объект на поверхности Земли. Приведены формулы расчета, проиллюстрированы результаты исследования.
The article describes process of modeling and analysis of influence of Moon's and Sun's tidal forces on an object, situated on Earth surface. Also, calculation formulas and illustrations of results are given.

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Держатели документа:
Институт Вычислительного моделирования СО РАН
Национальный исследовательский Томский политехнический университет

Доп.точки доступа:
Кочнев, Владимир Алексеевич; Kochnev V.A.; Chubarov D.L.; Федеральное агенство научных организаций; Уральское отделение РАН; Российская академия наукИнститут геофизики им Ю.П. Булашевича; Российский фонд фундаментальных исследований; Восьмые научные чтения памяти Ю.П. Булашевича "Глубинное строение, геодинамика, тепловое поле Земли, интерпретация геофизических полей" (2015 ; 14.09 - 18.09 ; Екатеринбург)

/ I. V. Zenkov, I. M. Baradulin // Gorn. Zh. - 2016. - Vol. 2016, Is. 3. - С. 85-88, DOI 10.17580/gzh.2016.03.18 . - ISSN 0017-2278
Аннотация: Slow-rate development of mineral resources in Siberia is connected with remoteness of mineral fields and deficiency in hard-surface roads. The approval of the government transport system program in Siberia requires boosting road metal production and quarrying expansion. Mined-out voids of depleted quarries disturb lands and remain bare for a long time. The situation in the Krasnoyarsk Territory is of particular concern. It is urgently required to find planting methods for mined-out ballast quarries. The obstacle is the traditional geometry of mined-out open pits, with steep walls and vast bottom flooded with atmospheric precipitations. Ecological monitoring of mined-out surface mines in the Krasnoyarsk Territory and most effective vegetation of mined-out voids shows that, given the local climate (long cold winter and short hot summer), population of trees is higher on the southern and eastern pit walls, where moisture content is higher and trees are less dehumidified under the sun in simmer; of no less significance is flatness of slopes and weak inclination (3-5°) of roads towards pit walls, as well as presence of fertile soil layer in the walls. On special purpose plots of land 0.2 ha in area, trees have been counted per each element of a quarry, which makes the basis to develop recommendations on environmentally optimal shape of quarries: maximum area of the southern and eastern pitwalls to be slightly sloping (15-24°), minimum technologically reasoned area of bottom is shifted northwestward. The study is in accordance with the Fundamental Research Program of the National Academies of Sciences for 2013-2020 and the research plan of the Nauka Design and Engineering Center, ICT SB RAS for 2013-2017, under the project "Information Support Models and Technologies for Evaluation, Forecasting and Management of Regional Eco-Systems, Territorial Infrastructure and Natural and Industrial Safety".

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Держатели документа:
Institute of Computational Technologies, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk, Russian Federation
Siberian Federal University, Krasnoyarsk, Russian Federation
Nauka Design and Engineering Center, Krasnoyarsk Division

Доп.точки доступа:
Zenkov, I. V.; Baradulin, I. M.

[Text] / K. G. Lichtenegger [et al.] // J. Geophys. Res-Space Phys. - 2016. - Vol. 121, Is. 5. - P4718-4732, DOI 10.1002/2015JA022226. - Cited References:60. - H.I.M. Lichtenegger acknowledges support from the FWF project P24247-N16, and N.V. Erkaev, M. Gudel, K.G. Kislyakova, C.P. Johnstone, and H. Lammer 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, S11604-N16 "Radiation & Wind Evolution from T Tauri Phase to ZAMS and Beyond", and S11607-N16 "Particle/Radiative Interactions with Upper Atmospheres of Planetary Bodies Under Extreme Stellar Conditions." N.V. Erkaev, H. Lammer, and P. Odert acknowledges also support from the FWF project P27256-N27. N.V. Erkaev was also supported by the RFBR grant 15-05-00879-a. This research was conducted using resources provided by the Swedish National Infrastructure for Computing (SNIC) at the High Performance Computing Center North (HPC2N), Umea University, Sweden. The software used in this work was in part developed by the DOE-supported ASC/Alliance Center for Astrophysical Thermonuclear Flashes at the University of Chicago. The data can be provided by H. I. M. Lichtenegger (herbert.lichtenegger@oeaw.ac.at) and K.G. Kislyakova (kristina.kislyakova@oeaw.ac.at). . - ISSN 2169-9380. - ISSN 2169-9402РУБ Astronomy & Astrophysics

Аннотация: We present a study on the influence of the upper atmosphere hydrodynamic escape of hydrogen, driven by the solar soft X-ray and extreme ultraviolet radiation (XUV), on an expected outgassed steam atmosphere of early Venus. By assuming that the young Sun was either a weak or moderately active young G star, we estimated the water loss from a hydrogen dominated thermosphere due to the absorption of the solar XUV flux and the precipitation of solar wind produced energetic hydrogen atoms (ENAs). The production of ENAs and their interaction with the hydrodynamic extended upper atmosphere, including collision-related feedback processes, have been calculated by means of Monte Carlo models. ENAs that collide in the upper atmosphere deposit their energy and heat the surrounding atmosphere mainly above the main XUV energy deposition layer. It is shown that precipitating ENAs modify the thermal structure of the upper atmosphere, but the enhancement of the thermal escape rates caused by these energetic hydrogen atoms is negligible. Our results also indicate that the majority of oxygen arising from dissociated H2O molecules is left behind during the first 100Myr. It is thus suggested that the main part of the remaining oxygen has been absorbed by crustal oxidation.

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Держатели документа:
Austrian Acad Sci, Space Res Inst, Graz, Austria.
SB RAS, Inst Computat Modelling, Krasnoyarsk, Russia.
Siberian Fed Univ, Polytech Inst, Krasnoyarsk, Russia.
Univ Arizona, Dept Planetary Sci, Tucson, AZ 85721 USA.
Univ Vienna, Dept Astrophys, Vienna, Austria.
Arizona State Univ, Sch Earth & Space Explorat, Tempe, AZ USA.
Swedish Inst Space Phys, Kiruna, Sweden.

Доп.точки доступа:
Lichtenegger, H. I. M.; Kislyakova, K. G.; Odert, N. V.; Erkaev, N. V.; Lammer, H.; Groller, C. P.; Johnstone, C. P.; Elkins-Tanton, L.; Tu, M.; Gudel, M.; Holmstrom, M.; FWF [P24247-N16, P27256-N27]; FWF NFN [S11601-N16, S11604-N16, S11607-N16]; RFBR [15-05-00879-a]

/ 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.

/ D. L. Chubarov, V. A. Kochnev, D. A. Terre // IOP Conf. Ser. Earth Envir. Sci. : IOP PUBLISHING LTD, 2016. - Vol. 43: 20th International Scientific Symposium of Students, Postgraduates and (APR 04-08, 2016, Inst Nat Resources, Tomsk, RUSSIA). - Ст. 012024. - (IOP Conference Series-Earth and Environmental Science), DOI 10.1088/1755-1315/43/1/012024. - Cited References:5 . - РУБ Energy & Fuels + Engineering, Petroleum + Engineering, Geological

Аннотация: The largest part of solid minerals (with the exception of those which are at the earth's surface) is being extracted world-wide by surface and underground mining techniques, with adits, mines and other mine workings being used. A considerable amount of mineral deposits (including oil reservoirs) is located either close to a fault-line or immediately within the zone of high seismic activity. To prevent economic and environmental damage under the effect of an earthquake, thorough seismic monitoring of the area must be performed, as well as the study of all possible mechanisms of an earthquake occurrence. In analysing the trigger effect of moon-and sun-induced tidal forces on seismic activity, six great earthquakes which occurred close to equatorial latitude over the last 15 years have been considered. Based on the positions of the Sun and Moon during the day relative to the point mass, the maps of horizontal, vertical components and vector of gravitational forces per unit mass have been plotted. The developed technique can be applicable to a set of methods to study integration and stress unloading mechanisms at the boundaries of block structures.

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Держатели документа:
Natl Res Tomsk Polytech Univ, 30 Lenin Ave, Tomsk, Russia.
Russian Acad Sci, Siberian Branch, Inst Computat Modeling, 50 Acad Gorodok, Krasnoyarsk, Russia.

Доп.точки доступа:
Chubarov, D. L.; Kochnev, V. A.; Terre, D. A.

[Текст] : статья / Даниил Леонидович Чубаров, Владимир Алексеевич Кочнев // Известия Томского политехнического университета. Инжиниринг георесурсов. - 2016. - Т. 327, № 2. - С. 59-64 . - ISSN 2500-1019

УДК	550.34.013.4

Аннотация: Большая часть твердых полезных ископаемых в мире (за исключением тех, что находятся на поверхности земли) добывается открытым и закрытым способом посредством штолен, шахт и других горных выработок. Немалая часть месторождений полезных ископаемых (в том числе и нефтяных) располагаются либо вблизи, либо непосредственно внутри зон повышенной сейсмологической активности (сюда можно отнести все месторождения Чили, Японии, Индонезии, некоторые месторождения США, России и других стран). Таким образом, если вблизи данных месторождений произойдет крупное землетрясение, то, вероятнее всего, это приведет, с одной стороны, к приостановке (или консервации) деятельности месторождения, с другой - к значительному числу жертв и экономическому ущербу. Чтобы избежать или хотя бы минимизировать данный ущерб, необходимо проводить полноценный сейсмологический мониторинг данных территорий, а также изучать все возможные причины возникновения землетрясений. Данная работа направлена на изучение природы землетрясений, что, несомненно, говорит об актуальности исследования. Цель данного исследования: установить совместное триггерное воздействие гравитационных сил Луны и Солнца на сейсмологическую активность зон Земли. Методы исследования. В данной работе за основу взята известная физико-математическая модель (приливная модель Дж. Дарвина), а таrже принято во внимание изменение относительного положения Луны и Солнца. Результаты. При изучении триггерного воздействия приливных сил на сейсмологическую активность рассмотрены 6 наиболее крупных землетрясений, произошедших вблизи экваториальной широты за последние 15 лет. Построены изображения горизонтальных, вертикальных компонент и модулей вектора гравитационных сил на единичную массу в зависимости от взаимного положения Луны и Солнца в течение суток относительно исследуемого объекта с единичной массой. Проанализировано воздействие приливных сил на точки эпицентров 6 крупнейших землетрясений, произошедших вблизи экваториальной широты. Разрабатываемая технология может быть полезна в комплексе методов при изучении механизмов интегрирования и разрядки напряжений на границах блоковых структур.
The majority of solid minerals in the world (excluding those, which are on the Earth’s surface) are mined by the open- and close-cut techniques using adits, mines and other minings. A large part of deposits of minerals (including the oil ones) occur either close or just inside the areas of higher seismological activity (all deposits in Chilly, Japan, Indonesia, some deposits in the USA, Russia and other countries can be referred to this type). Thus, if a major earthquake occurs near such deposit it will probably result in suspension (conservation) of the deposit activity, on the one hand, and on the other hand in significant amount of victims and economic damage. In order to avoid or at least to minimize the damage it is necessary to monitor the seismological situation in these territories and to study all possible causes of earthquake occurrence. The paper is devoted to the study of the earthquake nature. This is the relevance of the research. The aim of the study is to establish the combined effect of the gravitational forces of the Moon and Sun on the Earth’s seismological activity zones. Methods. Physical and mathematical model (G. Darwin tidal model) is taken as a basis, and the combined effect of the Moon and Sun and their relative positions are taken into account. Results. The authors have studied six largest earthquakes with epicenters located near the equator during the last 15 years and prepared a map of horizontal and vertical components and the magnitudes of gravitational force, depending on the relative position of the moon and the sun. The influence of tidal forces on epicenters of six greatest earthquakes, located near the equator, was analyzed. The developed technique can be useful for studying the mechanisms of stress at the boundaries of block structures.

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Держатели документа:
Институт вычислительного моделирования СО РАН
Национальный исследовательский Томский политехнический университет

Доп.точки доступа:
Кочнев, Владимир Алексеевич; Kochnev V.A.