Оглавление
Изображения
Загрузить ваше изображение
DSS Images Other Images
Публикации по объекту
Photopolarimetric activity and circumstellar environment of the young binary system DF Tau
We present the results of multi-year photometric and polarimetricobservations of the young binary system DF Tau in the UBVRI bands, aswell as bispectrum speckle interferometric observations in the H and Kbands obtained between 2001 and 2003. The photometric and polarimetricobservations suggest that the linear polarization of DF Tau does notdepend on its brightness, and the polarization variation has astochastic character. This result confirms earlier suggestions about thedominant role of hot accretion spots in the photometric activity of thisstar. We argue that the hot spots are at high latitudes and/or the starrotation axis is inclined to the line-of-sight. The influence ofcircumstellar (CS) dust on the variability is probably small since theinclination of the primary's CS disk to the line-of-sight is large.Using the total mass of the binary system DF Tau from Hartigan &Kenyon (2003, ApJ, 583, 334), we calculated new orbital parameters ofthe system. The new value of the orbital period (P = 74.1 yr) disagreeswith the photometric cycle of about 40 yr revealed by Lamzin et al.(2001b, A&A, 372, 922) from analysis of the historical light curveof this star. This suggests that this cycle is not caused by the orbitalmotions of the binary components, but probably reflects the cyclicalvariability of the global magnetic field on the main component.
| The Henry Draper Extension Charts: A catalogue of accurate positions, proper motions, magnitudes and spectral types of 86933 stars
The Henry Draper Extension Charts (HDEC), published in the form offinding charts, provide spectral classification for some 87000 starsmostly between 10th and 11th magnitude. This data, being highlyvaluable, as yet was practically unusable for modern computer-basedastronomy. An earlier pilot project (Roeser et al. 1991) demonstrated apossibility to convert this into a star catalogue, using measurements ofcartesian coordinates of stars on the charts and positions of theAstrographic Catalogue (AC) for subsequent identification. We presenthere a final HDEC catalogue comprising accurate positions, propermotions, magnitudes and spectral classes for 86933 stars of the HenryDraper Extension Charts.
| Polarimetric investigation of background stars in the region of T and RY Tau
Electropolarimetric observations of 97 background stars in the TTauri/RY Tauri region, obtained with the 40-cm Cassegrain telescope ofthe Biurakan Astrophysical Observatory in December 1982, are reportedand interpreted in terms of local-magnetic-field effects oncometary-nebula bending. The data are presented in a table, and thedependence of polarization position angle on declination is establishedin a graph and attributed to a continuous variation in the direction ofthe magnetic field. From the magnitude of the effect, however, it isconcluded that the observed bending of the cometary nebulae in theregion results from the combined influence of the local magnetic momentand the magnetic moment of the star itself (as proposed by Vardanian,1983) rather than from the local moment alone.
| Interstellar extinction in the dark Taurus clouds. I
The results of photoelectric photometry of 74 stars in the Vilniusseven-color system in the area of Taurus dark clouds with coordinates(1950) 4h20m-4h48m +24.5 deg to +27 deg are presented. Photometricspectral types, absolute magnitudes, color excesses, interstellarextinctions and distances of the stars are determined. The dark cloudKhavtassi 286, 278 and the surrounding absorbing nebulae are found toextend from 140 to 175 pc from the sun. The average interstellarextinction on both sides of the dark cloud is of the order of 1.5m. Noevidence of the existence of several absorbing clouds situated atvarious distances is found.
|
Добавить новую статью
Внешние ссылки
- - Внешних ссылок не найдено -
Добавить внешнюю ссылку
Группы:
|
Наблюдательные данные и астрометрия
| Созвездие: | Телец |
| Прямое восхождение: | 04h27m59.56s |
| Склонение: | +25°43'07.6" |
| Видимая звёздная величина: | 9.37 |
| Собственное движение RA: | 15.1 |
| Собственное движение Dec: | -9 |
| B-T magnitude: | 11.565 |
| V-T magnitude: | 9.552 |
Каталоги и обозначения:
|
