Astronomy:RT Virginis

From HandWiki
Short description: Star in the constellation Virgo
RT Virginis
RTVirLightCurve.png
A visual band light curve for RT Virginis, plotted from ASAS data[1]
Observation data
Equinox J2000.0]] (ICRS)
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]
Astrometry
Radial velocity (Rv)17.3±0.2[4] km/s
Proper motion (μ) RA: +37.037[2] mas/yr
Dec.: −17.714[2] mas/yr
Parallax (π)4.417 ± 0.134[3] mas
Distance740 ± 20 ly
(226 ± 7 pc)
Absolute magnitude (MV)2.94[6]
Details
Mass1.5[8] M☉
Radius390[9] R☉
Luminosity (bolometric)5,012+1,154
−938[4] L☉
Surface gravity (log g)+0.21[10] cgs
Temperature2,902[10] K
Metallicity [Fe/H]−0.33[10] dex
Other designations
RT Vir, BD+05°2708, HD 113285, HIP 63642, SAO 119734, PPM 159423[11]
Database references
SIMBADdata

RT Virginis is a variable star in the equatorial constellation of Virgo, abbreviated RT Vir. It ranges in brightness from an apparent visual magnitude of 7.7 down to 9.7,[3] which is too faint to be visible to the naked eye. Based on parallax measurements made with the VLBI, the distance to this star is approximately 740 light years.[3] It is receding from the Sun with a radial velocity of 17 km/s.[4]

The long period variability of this star was discovered by W. P. Fleming in 1896, based on photographic plates taken between 1886 and 1895.[12] A. H. Joy in 1942 categorized it as an irregular variable with a stellar classification of M8III.[5] In 1969 it was classified as a 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 astronomical unit|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

  1. ↑ ASAS All Star Catalogue, The All Sky Automated Survey, http://www.astrouw.edu.pl/asas/?page=aasc, retrieved 16 September 2022. 
  2. ↑ 2.0 2.1 2.2 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.
  3. ↑ 3.0 3.1 3.2 3.3 Zhang, Bo et al. (November 2017), "VLBA Trigonometric Parallax Measurement of the Semi-regular Variable RT Vir", The Astrophysical Journal 849 (2): 99, doi:10.3847/1538-4357/aa8ee9, 99, Bibcode: 2017ApJ...849...99Z. 
  4. ↑ 4.0 4.1 4.2 4.3 Brand, J. et al. (December 2020), "Water vapour masers in long-period variable stars. II. The semi-regular variables R Crt and RT Vir", Astronomy and Astrophysics 644: A45, doi:10.1051/0004-6361/202039157, A45, Bibcode: 2020A&A...644A..45B. 
  5. ↑ 5.0 5.1 Joy, Alfred H. (November 1942), "A Survey of the Spectra and Radial Velocities of the Less Regular M-Type Variable Stars", Astrophysical Journal 96: 344, doi:10.1086/144469, Bibcode: 1942ApJ....96..344J. 
  6. ↑ 6.0 6.1 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A. 
  7. ↑ Samus, N. N. et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1 61 (1): 80–88, doi:10.1134/S1063772917010085, Bibcode: 2017ARep...61...80S. 
  8. ↑ 8.0 8.1 Yates, J. A. et al. (2002), Mineese, Victor; Reid, Mark, eds., "The H2O maser proper motions of RT Vir and VX Sgr", Cosmic Masers: From Proto-Stars to Black Holes, IAU Symposium (San Francisco: Astronomical Society of the Pacific) 206: 298, Bibcode: 2002IAUS..206..298Y. 
  9. ↑ 9.0 9.1 9.2 Imai, H. et al. (March 1997), "Measurement of shifts in line-of-sight velocities of stellar water masers using VLBI.", Astronomy and Astrophysics 319: L1–L4, Bibcode: 1997A&A...319L...1I. 
  10. ↑ 10.0 10.1 10.2 Sharma, Kaushal et al. (2016), "New atmospheric parameters and spectral interpolator for the MILES cool stars", Astronomy and Astrophysics 585: A64, doi:10.1051/0004-6361/201526111, Bibcode: 2016A&A...585A..64S. 
  11. ↑ "RT Vir". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=RT+Vir. 
  12. ↑ Pickering, E. C.; Fleming, W. P. (April 1896), "Harvard College Observatory, circular no. 6. New variable stars", Astrophysical Journal 3: 296–302, doi:10.1086/140219, Bibcode: 1896ApJ.....3..296P. 
  13. ↑ van der Veen, W. E. C. J. et al. (March 1995), "The distribution of dust around Asymptotic Giant Branch stars", Astronomy and Astrophysics 295: 445–458, Bibcode: 1995A&A...295..445V. 
  14. ↑ Dickinson, D. F. (March 1976), "Water emission from infrared stars", Astrophysical Journal Supplement Series 30: 259–271, doi:10.1086/190362, Bibcode: 1976ApJS...30..259D. 
  15. ↑ 15.0 15.1 Mendoza-Torres, J. E. et al. (December 1997), "Evolution of H2O maser emission in the direction of the semiregular variable RT Virginis during 1985-1996", Astronomy and Astrophysics Supplement Series 126 (2): 257–266, doi:10.1051/aas:1997263, Bibcode: 1997A&AS..126..257M. 
  16. ↑ Sacuto, S. et al. (March 2013), "The wind of the M-type AGB star RT Virginis probed by VLTI/MIDI", Astronomy and Astrophysics 551: A72, doi:10.1051/0004-6361/201220524, A72, Bibcode: 2013A&A...551A..72S. 
  17. ↑ Yates, J. A. et al. (2000), Kastner, J. H.; Soker, N.; Rappaport, S., eds., "Is the Outflow from RT Vir Bipolar or Rotating?", Asymmetrical Planetary Nebulae II: From Origins to Microstructures, ASP Conference Series 199: 79, ISBN 1-58381-026-9, Bibcode: 2000ASPC..199...79Y. 

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, doi:10.1086/374887, Bibcode: 2003ApJ...590..460I. 
  • 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, doi:10.1051/0004-6361:20011184, Bibcode: 2001A&A...378..522E. 
  • 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.; Lebre, A.; Waelkens, C., eds., "A MERLIN movie of mass-loss from RT Vir", Asymptotic Giant Branch Stars, IAU Symposium 191: 315, ISBN 1-886733-90-2, Bibcode: 1999IAUS..191..315R. 




Retrieved from "https://handwiki.org/wiki/index.php?title=Astronomy:RT_Virginis&oldid=3344124"