Structure of the inner region of the accretion disk of the Herbig Ae star CQ Tau based on long-term monitoring data

Козлова, О. В.; Shakhovskoi, D. N.; Rostopchina, A. N.; Alekseev, I. Yu.

doi:10.1007/s10511-007-0004-z

Cited by 3 publications

(2 citation statements)

References 10 publications

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“…Similar times for the variability of the parameters of the Hα emission line and the sodium resonance doublet have been observed in the Herbig Ae-star CQ Tau [28]. These observations show that the inner structure of this star's accretion disk varies over a time scale close to 1000 days.…”

Section: Resultssupporting

confidence: 75%

Structure of the inner regions of the circumstellar gas envelopes around young hot stars. II. The new cycle of spectral activity of the Herbig Ae star HD 31648

2007

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The results of the high-resolution long-term spectral monitoring of the Herbig Ae star HD 31648 in the regions of emission Hα line, Na I D resonance lines and OI 7774 lines are presented. We confirmed the conclusion, made in previous papers, that the spectral variability of the star in the region of Hα line have a cyclic character. It is manifested itself as the changing of the equivalent width and intensity of Hα line of the time scale of about 1200d. It is shown, that the stellar wind is non-homogeneous and consists of several components, which are differed each other by their velocities. They are observed as in the H line as in Na I D resonance lines. The component's parameters are changed during the cycle of stellar activity (in the maximum of activity the velocity and density of the wind are taken the largest values and then they are gradually decreased). The investigation of rapid variability of the He I 5876 line on the time scale of a few hours allows find the correlation between the variability of the blue and the red wings of the line. It points at the connection between the accretion and the outflows. Such connection, in particularly, is predicted by the modeling of the wind from young stars made in the frame of the magneto-centrifugal model, the accordance of which for the HD 31648 was shown in the previous papers. In the present work we confirmed this conclusion on the basis of the new data.We found the weak variability of the stellar brightness (about 0.2m), which is agree with the spectral variability (the brightness of the star becomes lower in the maximum of the activity). These changes are well explained by the process of the dust transfer from CS disk by the stellar wind. This process is likely to be more effective in the maximum of activity.An analysis of the variability of other spectral lines shows the agreement between the changing of the Hα line, the Na I D resonance doublet lines and KI 7698 line. The weak connection between the He I 5876 and the Na I D lines is also found. Since the formation regions of He I 5876 and Na I D lines are essentially different, we can conclude that the phenomena, responsible for the observed cyclic variability, take place in a spacious region of the CS envelope. We believe that the most plausible reason of found cyclic variability is the reconstruction of the inner structure of the CS gas envelope, caused by the presence around the star a low mass companion or planet.

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Section: Resultssupporting

confidence: 75%

Structure of the inner regions of the circumstellar gas envelopes around young hot stars. II. The new cycle of spectral activity of the Herbig Ae star HD 31648

2007

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“…In this context, there must be pointed out the data of a spectral study of the CQ Tau star (Kozlova et al, 2007b). The shortest of photometric periods of the star accounts for about 1000 (Shakhovskoi et al, 2005), which is close to the spectral variability scale of CQ Tau (about 700 ).…”

Section: Discussionmentioning

confidence: 96%

A study of many-year spectral variability of the Ae Herbig star HD 36112

Fursyak

Козлова

2021

Acta Astrophys. Tau.

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We present the results of long-term high-dispersion spectral observations (R = 20000) of the Ae Herbig star HD 36112 in the regions of the Ha emission line and the NaI D resonance doublet lines. They show that parameters of the Ha emission line demonstrate complicated variability on several time scales: 1) variability from night to night caused by inhomogeneity of the circumstellar envelope; 2) variability on a time scale of about 1200d characterized by a variation of the equivalent width, intensity, and other emission parameters; 3) variability on a time scale of more than 4000d observed as a many-year trend in variations of parameters of the Ha emission line. We associate these results with variability of physical and kinematic conditions in the inner regions of the accretion disk and wind. The most probable mechanism of this variability is a process of planet formation in the circumstellar disk.

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Исследование многолетней спектральной переменности Ae звезды Хербига HD 36112

Фурсяк¹,

Козлова²

2020

Изв. Крымск. Астрофиз. Обсерв.

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Представлены результаты многолетних высокодисперсионных спектральных наблюдений (R = 20000) Ае звезды Хербига HD 36112 в области эмиссионных линий Hα и резонансного дублета NaI D. Показано, что параметры эмиссионной линии Hα демонстрируют сложную переменность на нескольких временных шкалах: 1) переменность от ночи к ночи, обусловленную неоднородной структурой околозвездной газовой оболочки; 2) переменность на шкале времени около 1200 суток, характеризующуюся изменением эквивалентной ширины, интенсивности, а также других параметров эмиссии; 3) переменность на шкале времени более 4000 суток, наблюдаемую как многолетний тренд в изменении параметров эмиссионной линии Hα.Мы связываем полученные результаты с изменением физических и кинематических условий во внутренних областях аккреционного диска и ветра. Наиболее вероятным механизмом таких изменений является активно идущий в околозвездном диске звезды процесс планетообразования.

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Structure of the inner region of the accretion disk of the Herbig Ae star CQ Tau based on long-term monitoring data

Cited by 3 publications

References 10 publications

Structure of the inner regions of the circumstellar gas envelopes around young hot stars. II. The new cycle of spectral activity of the Herbig Ae star HD 31648

Structure of the inner regions of the circumstellar gas envelopes around young hot stars. II. The new cycle of spectral activity of the Herbig Ae star HD 31648

A study of many-year spectral variability of the Ae Herbig star HD 36112

Исследование многолетней спектральной переменности Ae звезды Хербига HD 36112

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