التفاصيل البيبلوغرافية
| العنوان: |
Mysterious non-detection of He i (23S) transit absorption of GJ 436b. |
| المؤلفون: |
Rumenskikh, M S, Khodachenko, M L, Shaikhislamov, I F, Miroshnichenko, I B, Berezutsky, A G, Shepelin, A V, Dwivedi, N K |
| المصدر: |
Monthly Notices of the Royal Astronomical Society; Dec2023, Vol. 526 Issue 3, p4120-4129, 10p |
| مصطلحات موضوعية: |
CORONAL mass ejections, IONIZING radiation, STELLAR radiation, ABSORPTION, RADIATION pressure, HELIUM atom, HELIUM |
| مستخلص: |
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] |
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| قاعدة البيانات: |
Complementary Index |