RT Virginis
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Virgo |
| Right ascension | 13h 02m 37.981s[2] |
| Declination | +05° 11′ 08.36″[2] |
| Apparent magnitude (V) | 7.7 to 9.7[3] |
| Characteristics | |
| Evolutionary stage | AGB[4] |
| Spectral type | M8III[5] |
| B−V color index | 1.352±0.031[6] |
| Variable type | SRb[7] |
| Absolute magnitude (MV) | 2.94[6] |
| Details | |
dex | |
PPM 159423[11] | |
| Database references | |
| SIMBAD | data |
RT Virginis is a
The long period variability of this star was discovered by
semiregular variable star of the SRb type.[13] The period was determined to be 155 days by P. N. Kholopov and associates in 1985, then re-evaluated as 375 days based on AAVSO light curves in 1997. This is an oxygen-rich red giant star on the asymptotic giant branch of its evolution, and is undergoing mass loss due to thermal pulsation.[9]
Water vapor
emission in the vicinity of the star was detected in the microwave band by D. F. Dickinson in 1973.[14] This is originating from strong maser emission in a circumstellar gas-dust shell.[15] The flux density of these water masers is over 100 Jy.[9] The star is losing mass at a rate of 3×10−6 M☉·yr−1;[8] the equivalent of the Sun's mass in 3.3 million years. The velocity of the spherically expanding gas is as high as 11 km/s in the water maser region, at a radius of 5 to 25 AU. In a SiO emitting region located ~400 AU from the star, the gas velocity is 7.8 km/s.[16] This outflow appears clumpy and asymmetrical[17] with a strong temporal variation.[15]
References
- ^ ASAS All Star Catalogue, The All Sky Automated Survey, retrieved 16 September 2022.
- ^ .
- ^ S2CID 125975009, 99.
- ^ , A45.
- ^ doi:10.1086/144469.
- ^ S2CID 119257644.
- S2CID 125853869.
- ^ Bibcode:2002IAUS..206..298Y.
- ^ Bibcode:1997A&A...319L...1I.
- ^ S2CID 118576178.
- ^ "RT Vir", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2022-09-07
- doi:10.1086/140219.
- Bibcode:1995A&A...295..445V.
- doi:10.1086/190362.
- ^ .
- S2CID 18675130, A72.
- ISBN 1-58381-026-9.
Further reading
- Imai, Hiroshi; et al. (June 2003), "The Three-dimensional Kinematics of Water Masers around the Semiregular Variable RT Virginis", The Astrophysical Journal, 590 (1): 460–472, S2CID 18661079.
- Etoka, S.; et al. (November 2001), "Monitoring of long term behaviour of OH masers in semiregular variables: R Crt, W Hya and RT Vir", Astronomy and Astrophysics, 378 (2): 522–538, .
- Lekht, E. E.; et al. (March 1999), "Dynamics of the circumstellar envelope of RT Virginis on the basis of the H2O maser monitoring", Astronomy and Astrophysics, 343: 241–250, Bibcode:1999A&A...343..241L.
- Richards, A. M. S.; et al. (1999), Le Bertre, T.; et al. (eds.), "A MERLIN movie of mass-loss from RT Vir", Asymptotic Giant Branch Stars, IAU Symposium, 191: 315, ISBN 1-886733-90-2.
