11 results on '"E. S. Kalinicheva"'
Search Results
2. Differential Rotation of Stars in Spectral Class A
- Author
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E. S. Kalinicheva, E. S. Dmitrienko, and I. S. Savanov
- Subjects
Physics ,Brightness ,010308 nuclear & particles physics ,Astronomy and Astrophysics ,Astrophysics ,Star (graph theory) ,Light curve ,Stellar classification ,01 natural sciences ,Spectral line ,Stars ,0103 physical sciences ,Modulation (music) ,Astrophysics::Solar and Stellar Astrophysics ,Differential rotation ,Astrophysics::Earth and Planetary Astrophysics ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
Published data indicate a substantial increase in the differential rotation parameter ∆Ω of stars hotter than 6700 K. By analyzing the shape of the light curves and the presence of a specific set of peaks in their power spectra, we have found that 47 of 57 objects with Teff greater than 7500 K that were studied can be identified as pulsating stars and only 10, as stars with brightness variation owing to rotational modulation. After eliminating the pulsating variables, for the stars with Teff greater than 7500 K the average value of ∆Ω= 0.051±0.01 rad/day. This conclusion conflicts with our earlier assumption that the peaks in the power spectra for ROTD stars are caused by a possible manifestation of differential rotation. Further independent evidence for a low value of ∆Ω for stars in spectral class A has been obtained from Zeeman-Doppler charts for the star γ Gem, with an estimate for the differential rotation parameter of the star of 0.0073±0.0023 rad/day.
- Published
- 2020
3. Oxygen Atom Escape from the Martian Atmosphere during Proton Auroral Events
- Author
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V. I. Shematovich and E. S. Kalinicheva
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Physics ,Proton ,Solar flare ,010308 nuclear & particles physics ,Astronomy and Astrophysics ,Mars Exploration Program ,Atmosphere of Mars ,01 natural sciences ,Solar wind ,Space and Planetary Science ,Physics::Space Physics ,0103 physical sciences ,Coronal mass ejection ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Atomic physics ,Thermosphere ,010303 astronomy & astrophysics ,Exosphere - Abstract
We present the model calculation results of the atomic oxygen loss rate from the Martian atmosphere induced by precipitation of high-energy protons and hydrogen atoms (H/H+) from the solar wind plasma. Penetration of energetic protons and hydrogen atoms from the solar wind plasma to the upper atmosphere of Mars at altitudes of 100−250 km is accompanied by the momentum and energy transfer in collisions with the main component, atomic oxygen. This process is considered as atmospheric gas sputtering during proton auroral events, which is accompanied by formation of the suprathermal hydrogen and oxygen atom fluxes escaping from the atmosphere. When calculating the formation rate of suprathermal atoms, the modified Monto Carlo kinetic model was used. This model was earlier developed to analyze the data of the Analyzer of Space Plasma and Energetic Atoms (ASPERA-3) and the Solar Wind Ion Analyzer (SWIA) onboard the Mars Express (MEX) and the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft, respectively. We study the processes of kinetics and transport of hot oxygen atoms in the transition zone (from the thermosphere to the exosphere) of Mars’ upper atmosphere. The kinetic energy distribution functions for suprathermal oxygen atoms were calculated. It has been shown that, during proton auroral events on Mars, the exosphere is populated with a significant number of suprathermal oxygen atoms, the kinetic energy of which reaches the escape energy, 2 eV. In addition to photochemical sources, a hot fraction is formed in the oxygen corona; and a nonthermal flux of atomic oxygen escaping from the Martian atmosphere is produced during proton aurora events. Proton aurorae are sporadic auroral events. Consequently, according to the estimates obtained from the recent MAVEN observations the magnitude of the precipitation-induced escaping flux of hot oxygen atoms may become prevailing over the photochemical sources under conditions of the extreme solar events such as solar flares and coronal mass ejections.
- Published
- 2020
4. On the thermal atmosphere evaporation of hot neptune GJ 436b
- Author
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E. S. Kalinicheva, V. I. Shematovich, and Ya. N. Pavlyuchenkov
- Subjects
Atmosphere ,Materials science ,Atmospheric escape ,Thermal ,Evaporation ,Hot Neptune ,Exoplanet ,Astrobiology - Abstract
В данной работе с помощью одномерной самосогласованной аэрономической модели были получены высотные профили температуры, скорости и плотности для горячего нептуна GJ 436b. Мы проследили расширение газовой оболочки под действием нагрева от жесткого излучения родительской звезды от тонкого атмосферного слоя 1.02R 0 до 5R 0 . Используемая модель учитывает вклад надтепловых частиц, что значительно уточняет функцию нагрева атмосферы. Установлено, что формируется структура атмосферы с двумя характерными шкалами высоты, отвечающими относительно плотной атмосфере и более разреженной короне. Также был посчитан темп оттока атмосферы, составивший около 1.6 × 10 9 г с -1 , что ниже результатов, полученных авторами других расчетов. In this work the height profiles of temperature, velocity, and density were obtained for the hot neptune GJ 436b, using a one-dimensional self-consistent aeronomic model. We traced the expansion of the gas envelope affected by heating from the extreme radiation of the host star from the thin atmospheric layer 1.02R 0 up to 5R 0 . The model used takes into account the contribution of suprathermal particles, which significantly refines the atmospheric heating function. It was found that the structure of the atmosphere is being formed with two characteristic altitude scales corresponding to a relatively dense atmosphere and a more rarefied corona. The atmospheric mass loss rate was also calculated, it was found to be about 1.6 × 10 9 g s -1 , which is lower than the results obtained by the authors of other calculations.
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- 2020
5. On the thermal atmospheric escape of π Men c
- Author
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E. S. Kalinicheva, V. I. Shematovich, and Ya. N. Pavlyuchenkov
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Materials science ,Atmospheric escape ,Thermal ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Atomic physics ,Physics::Atmospheric and Oceanic Physics - Abstract
In this work we present the results of the modeling of exoplanet pi Men c upper atmosphere, produced using the previously developed one-dimensional self-consistent aeronomic model. The model used takes into account the contribution of suprathermal particles, which significantly refines the heating function of the atmosphere. The hight profiles of temperature, velocity and density were obtained, the atmospheric mass-loss rate was calculated. The presence of two hight-scales in the structure of the atmosphere was found: the first corresponds to a relatively dense stationary atmosphere, the second to a more rarefied corona.
- Published
- 2021
6. Comparative Analysis of the Model for Exoplanet Atmosphere Outflow
- Author
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Ya. N. Pavlyuchenkov, V. I. Shematovich, E. S. Kalinicheva, and P. B. Isakova
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Physics ,Earth and Planetary Astrophysics (astro-ph.EP) ,Correctness ,010308 nuclear & particles physics ,business.industry ,Theoretical models ,FOS: Physical sciences ,Astronomy and Astrophysics ,01 natural sciences ,Exoplanet ,Atmosphere ,Space and Planetary Science ,0103 physical sciences ,Outflow ,Astrophysics::Earth and Planetary Astrophysics ,Aerospace engineering ,business ,010303 astronomy & astrophysics ,Astrophysics - Earth and Planetary Astrophysics - Abstract
Modeling the outflow of planetary atmospheres is important for understanding the evolution of exoplanet systems and for interpreting their observations. Modern theoretical models of exoplanet atmospheres become increasingly detailed and multicomponent, and this makes difficulties for engaging new researchers in the scope. Here, for the first time, we present the results of testing the gas-dynamic method incorporated in our aeronomic model, which has been proposed earlier. Undertaken tests support the correctness of the method and validate its applicability. For modeling the planetary wind, we propose a new hydrodynamic model equipped with a phenomenological function of heating by stellar UV radiation. The general flow in this model well agrees with results obtained in more detailed aeronomic models. The proposed model can be used for both methodical purposes and testing the gas-dynamic modules of self-consistent chemical-dynamic models of the planetary wind., Comment: 8 pages, 6 figures, accepted for publication in Astronomy Reports (2021)
- Published
- 2021
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7. ATMOSPHERIC ESCAPE OF CLOSE-IN NEPTUNES
- Author
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E. S. Kalinicheva, Ya. N. Pavlyuchenkov, and V. I. Shematovich
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Atmospheric escape ,Environmental science ,Astrobiology - Published
- 2020
8. About the Differential Rotation of A-type Stars
- Author
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E. S. Kalinicheva, I. S. Savanov, and E. S. Dmitrienko
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Physics ,Starspot ,Differential rotation ,Astrophysics ,A-type main-sequence star - Published
- 2020
9. About the Atmospheric Loss of Hot Neptune GJ436b
- Author
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Ya. N. Pavlyuchenkov, V. I. Shematovich, and E. S. Kalinicheva
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Environmental science ,Hot Neptune ,Astrobiology - Published
- 2020
10. DIFFERENTIAL ROTATION OF A-TYPE STARS
- Author
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E. S. Dmitrienko, I. S. Savanov, and E. S. Kalinicheva
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Physics ,Differential rotation ,Astrophysics ,A-type main-sequence star - Published
- 2020
11. The Spots and Activity of Stars in the Beehive Cluster Observed by the Kepler Space Telescope (K2)
- Author
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E. S. Dmitrienko, I. S. Savanov, and E. S. Kalinicheva
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Physics ,Rotation period ,Beehive ,010308 nuclear & particles physics ,Astronomy and Astrophysics ,Astrophysics ,Rotation ,01 natural sciences ,Rossby number ,Stars ,Spitzer Space Telescope ,Space and Planetary Science ,0103 physical sciences ,Cluster (physics) ,Pleiades ,010303 astronomy & astrophysics - Abstract
The spottedness parameters S (the fraction of the visible surface of the star occupied by spots) characterizing the activity of 674 stars in the Beehive Cluster (age 650 Myr) are estimated, together with variations of this parameter as a function of the rotation period, Rossby number Ro and other characteristics of the stars. The activity of the stars in this cluster is lower than the activity of stars in the younger Pleiades (125 Myr). The average S value for the Beehive Cluster stars is 0.014, while Pleiades stars have the much higher average value 0.052. The activity parameters of 61 solar-type stars in the Beehive Cluster, similar Hyades stars (of about the same age), and stars in the younger Pleiades are compared. The average S value of such objects in the Beehive Cluster is 0.014± 0.008, nearly coincident with the estimate obtained for solar-type Hyades stars. The rotation periods of these objects are 9.1 ± 3.4 day, on average, in agreement with the average rotation period of the Hyades stars (8.6 d ). Stars with periods exceeding 3–4 d are more numerous in the Beehive Cluster than in the Pleiades, and their periods have a larger range, 3–30 d . The characteristic dependence with a kink at Ro (saturation) = 0.13 is not observed in the S–Rossby number diagram for the Beehive and Hyades stars, only a clump of objects with Rossby numbers Ro > 0.7. The spottedness data for the Beehive Cluster and Hyades stars are in good agreement with the S values for dwarfs with ages of 600–700 Myr. This provides evidence for the reliability of the results of gyrochronological calibrations. The data for the Beehive and Pleiades stars are used to analyze variations in the spot-forming activity for a large number of stars of the same age that are members of a single cluster. A joint consideration of the data for two clusters can be used to draw conclusions about the time evolution of the activity of stars of different masses (over a time interval of the order of 500 Myr).
- Published
- 2018
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