Study of the Carbon Star T Draconis

Tatarnikov, A.M.; Zheltoukhov, S.G.; Shenavrin, V.I.; Sergeenkova, I.V.; Vakhonin, A.A.

Авторы: Tatarnikov A.M., Zheltoukhov S.G., Shenavrin V.I., Sergeenkova I.V., Vakhonin A.A.
Журнал: Astronomy Letters
Том: 50
Номер: 1
Год издания: 2024
Издательство: Maik Nauka/Interperiodica Publishing
Местоположение издательства: Russian Federation
Первая страница: 51
Последняя страница: 63
Аннотация: We present the results of the infrared photometric observations in the JHKLM bands and infrared spectroscopic observations in the range 1–2.5 μm for the carbon Mira star T Dra performed from 2019 to 2023. An analysis of the photometric observations shows the presence of both pulsational brightness fluctuations with an amplitude falling from 1.2m in the J band to 0.84m in the L and M bands and a linear trend in the mean brightness with a value of 0.0007 mag/day in the J band. In the infrared spectrum of T Dra we have identified the absorption bands of C2H2, HCN, CN, CO, and C2 molecules. The depth of the absorption band at 1.53 μm has been found to depend on the star’s brightness. We show that the CO λ2.29 μm bands have a high contrast, suggesting their formation not in the stellar atmosphere but in the circumstellar dust envelope. We present the spectral energy distribution of T Dra in a wide spectral range from which the bolometric fluxes at maximum and minimum brightness have been estimated: 4.8e-10 and 2.5e-10 W/m^2, respectively. For the distance to T Dra of 944 pc they correspond to the star’s luminosity at maximum brightness Lmax ≈ 13 300 Lsun and at minimum brightness Lmin ≈ 6900 Lsun. We have modeled the radiative transfer in the circumstellar envelope of T Dra and estimated the parameters of the star and the envelope: Teff = 2400 K, R∗ = 670 Rsun, Rin = 5-6 AU, Rout ∼ 50 000 AU, τV = 3.5, Mdust = 4-8e-5Msun, and dM/dt ∼ 1.5e-6 Msun yr-1.
Добавил в систему: Татарников Андрей Михайлович

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Study of the Carbon Star T Draconisстатья

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