Study of the Carbon Star T Draconis.

We present the results of the infrared photometric observations in the bands and infrared spectroscopic observations in the range 1–2.5 m 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 in the band to in the and bands and a linear trend in the mean brightness with a value of in the band. In the infrared spectrum of T Dra we have identified the absorption bands of C H , HCN, CN, CO, and C molecules. The depth of the absorption band at 1.53 m has been found to depend on the star's brightness. We show that the CO m 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: and W m , respectively. For the distance to T Dra of 944 pc they correspond to the star's luminosity at maximum brightness and at minimum brightness . We have modeled the radiative transfer in the circumstellar envelope of T Dra and estimated the parameters of the star and the envelope: K, , AU, AU, , , and yr . [ABSTRACT FROM AUTHOR]