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Your search keyword '"Khodachenko, M. L."' showing total 402 results
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402 results on '"Khodachenko, M. L."'

52. Mysterious non-detection of He i (23S) transit absorption of GJ 436b.

Author

Rumenskikh, M S, Khodachenko, M L, Shaikhislamov, I F, Miroshnichenko, I B, Berezutsky, A G, Shepelin, A V, and Dwivedi, N K

Subjects
CORONAL mass ejections, IONIZING radiation, STELLAR radiation, ABSORPTION, RADIATION pressure, HELIUM atom, HELIUM
Abstract

Possible reasons for the non-detection of absorption in the metastable He  i (23S) line at transit observations of warm Neptune GJ436b, in spite of the well-pronounced strong absorption features measured earlier in Lyα for this planet, are investigated. We perform numeric simulations of the escaping upper atmosphere of this planet and its He  i (23S) triplet absorption with a global 3D multifluid, self-consistent hydrodynamic model. By fitting the model parameters to the lowest detection level of absorption measurements, we constrain an upper limit for the He/H abundance three times smaller than the solar value. We demonstrate that neither the significant changes of the stellar wind related to possible stellar coronal mass ejections (CMEs), or possible variations in the stellar ionization radiation, nor the presence of heavy trace elements have a crucial effect on the absorption at the 10   830 Å line of He  i (23S) triplet. The main reason of weak signature is that the region populated by the absorbing metastable helium is rather small (<3 R p), as well as the small size of the planet itself in comparison to the host star. We show that the radiation pressure force acting on the He  i (23S) atoms spreads them along the line of sight and around the planet, thus further reducing peak absorption. [ABSTRACT FROM AUTHOR]

Published
2023
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56. The GAPS Programme at TNG

Author

Fossati, L., primary, Guilluy, G., additional, Shaikhislamov, I. F., additional, Carleo, I., additional, Borsa, F., additional, Bonomo, A. S., additional, Giacobbe, P., additional, Rainer, M., additional, Cecchi-Pestellini, C., additional, Khodachenko, M. L., additional, Efimov, M. A., additional, Rumenskikh, M. S., additional, Miroshnichenko, I. B., additional, Berezutsky, A. G., additional, Nascimbeni, V., additional, Brogi, M., additional, Lanza, A. F., additional, Mancini, L., additional, Affer, L., additional, Benatti, S., additional, Biazzo, K., additional, Bignamini, A., additional, Carosati, D., additional, Claudi, R., additional, Cosentino, R., additional, Covino, E., additional, Desidera, S., additional, Fiorenzano, A., additional, Harutyunyan, A., additional, Maggio, A., additional, Malavolta, L., additional, Maldonado, J., additional, Micela, G., additional, Molinari, E., additional, Pagano, I., additional, Pedani, M., additional, Piotto, G., additional, Poretti, E., additional, Scandariato, G., additional, Sozzetti, A., additional, and Stoev, H., additional

Published
2022
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63. Exoplanet status report: Observation, characterization and evolution of exoplanets and their host stars

Author

Lammer, H., Hanslmeier, A., Schneider, J., Stateva, I. K., Barthelemy, M., Belu, A., Bisikalo, D., Bonavita, M., Eybl, V., Coudé du Foresto, V., Fridlund, M., Dvorak, R., Eggl, S., Grießmeier, J. -M., Güdel, M., Günther, E., Hausleitner, W., Holmström, M., Kallio, E., Khodachenko, M. L., Konovalenko, A. A., Krauss, S., Ksanfomality, L. V., Kulikov, Yu. N., Kyslyakova, K., Leitzinger, M., Liseau, R., Lohinger, E., Odert, P., Palle, E., Reiners, A., Ribas, I., Rucker, H. O., Sarda, N., Seckbach, J., Shematovich, V. I., Sozzetti, A., Tavrov, A., and Xiang-Grüß, M.

Published
2010
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65. What makes a planet habitable?

Author

Lammer, H., Bredehöft, J. H., Coustenis, A., Khodachenko, M. L., Kaltenegger, L., Grasset, O., Prieur, D., Raulin, F., Ehrenfreund, P., Yamauchi, M., Wahlund, J.-E., Grießmeier, J.-M., Stangl, G., Cockell, C. S., Kulikov, Yu. N., Grenfell, J. L., and Rauer, H.

Published
2009
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71. UV transit observations of EUV-heated expanded thermospheres of Earth-like exoplanets around M-stars: testing atmosphere evolution scenarios

Author

Lammer, H., primary, Eybl, V., additional, Kislyakova, K. G., additional, Weingrill, J., additional, Holmström, M., additional, Khodachenko, M. L., additional, Kulikov, Yu. N., additional, Reiners, A., additional, Leitzinger, M., additional, Odert, P., additional, Xiang Grüß, M., additional, Dorner, B., additional, Güdel, M., additional, and Hanslmeier, A., additional

Published
2011
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95. The energy‐based scaling of a thin current sheet: Case study

Author

Sasunov, Yu. L., Khodachenko, M. L., Alexeev, I. I., Belenkaya, E. S., Gordeev, E. I., and Kubyshkin, I. V.

Subjects
Solar Physics, Astrophysics, and Astronomy, adiabatic invariant, Energetic Particles, Kinetic and MHD theory, Cluster observation, Cosmic Rays, Research Letters, Interplanetary Physics, Particle Acceleration, Physics::Plasma Physics, current sheet, Physics::Space Physics, Plasma Sheet, Research Letter, Space Plasma Physics, Magnetospheric Physics, Space Sciences
Abstract

The influence of average plasma energy E~ on the half thickness ℓ of a thin current sheet (TCS) is investigated for three cases of TCSs crossings. The value of ℓ was estimated from the magnetic field data by means of Cluster observations. The obtained scaling values for TCSs, Z~=ℓ/ρT, where ρ T is the thermal Larmor radius, were compared with the scaling Zμ=22E~/T, where E~ and T are the average plasma energy and the temperature of plasma, which assumes a specific dynamics (conservation of magnetic flux through the trajectory segment) of the current carriers. The comparison of Z~ and Z μ shows a good agreement., Key Points The new scaling is presentedThe energy‐based scaling compared with observable thickness of TCSThe population of the TCS‐forming protons results in different scaling

Published
2015

99. Global 3D hydrodynamic modelling of absorption in Ly α and He 10830 A lines at transits of GJ3470b.

Author

Shaikhislamov, I F, Khodachenko, M L, Lammer, H, Berezutsky, A G, Miroshnichenko, I B, and Rumenskikh, M S

Subjects
ATMOSPHERE, ABSORPTION, HELIUM plasmas, UPPER atmosphere, STELLAR atmospheres, PLANETARY atmospheres
Abstract

Warm Neptune GJ3470b has been recently observed in 23S-23P transition of metastable helium, yielding absorption of about 1 per cent in Doppler velocity range of [−40; 10] km s−1. Along with previous detection of absorption in Ly α with depth of 20–40 per cent in the blue and red wings of the line, it offers a complex target for simulation and testing of the current models. Obtained results suggest that absorption in both these lines comes from interaction of expanding upper planetary atmosphere with stellar plasma wind, allowing to constrain the stellar plasma parameters and the helium abundance in planet atmosphere. [ABSTRACT FROM AUTHOR]

Published
2021
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100. Modeling of Absorption by Heavy Minor Species for the Hot Jupiter HD 209458b

Author

Shaikhislamov, I. F., primary, Khodachenko, M. L., additional, Lammer, H., additional, Fossati, L., additional, Dwivedi, N., additional, Güdel, M., additional, Kislyakova, K. G., additional, Johnstone, C. P., additional, Berezutsky, A. G., additional, Miroshnichenko, I. B., additional, Posukh, V. G., additional, Erkaev, N. V., additional, and Ivanov, V. A., additional

Published
2018
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