RT Virginis

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RT Virginis
RTVirLightCurve.png
A visual band light curve for RT Virginis, plotted from ASAS data [1]
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]
Astrometry
Radial velocity (Rv)17.3±0.2 [4]  km/s
Proper motion (μ)RA: +37.037  mas/yr [2]
Dec.: −17.714  mas/yr [2]
Parallax (π)4.417 ± 0.134  mas [3]
Distance 740 ± 20  ly
(226 ± 7  pc)
Absolute magnitude  (MV)2.94 [6]
Details
Mass 1.5 [8]   M☉
Radius 390 [9]   R☉
Luminosity (bolometric)5,012+1,154
−938 [4]   L☉
Surface gravity (log g)+0.21 [10]   cgs
Temperature 2,902 [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
SIMBAD data

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] It was listed with its variable star designation, RT Virginis, in Annie Jump Cannon's 1907 work Second Catalog of Variable Stars. [13] 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. [14] 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. [15] This is originating from strong maser emission in a circumstellar gas-dust shell. [16] 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. [17] This outflow appears clumpy and asymmetrical [18] with a strong temporal variation. [16]

Related Research Articles

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Delta Virginis, formally named Minelauva, is a star in the zodiac constellation of Virgo. With an apparent visual magnitude of 3.4, this star is bright enough to be seen with the naked eye. It is located at a distance of about 202 light-years from the Sun.

<span class="mw-page-title-main">Gamma Virginis</span> Star in the constellation Virgo

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<span class="mw-page-title-main">Tau Virginis</span> Star in the constellation Virgo

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Theta Virginis is a multiple star system in the zodiac constellation of Virgo. Based upon parallax measurements, it is about 320 light years from the Sun. The three stars in this system have a combined apparent visual magnitude of 4.37, bright enough to be seen with the naked eye.

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<span class="mw-page-title-main">Omega Virginis</span> Star in the constellation Virgo

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16 Virginis is a single star in the zodiac constellation of Virgo, located about 308 light years from the Sun. It has the Bayer designation c Virginis; 16 Virginis is the Flamsteed designation. This object is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.96. This is an IAU radial velocity standard star; it is moving further from the Earth with a heliocentric radial velocity of +37 km/s. The star has a relatively high proper motion, traversing the celestial sphere at an angular rate of 0.301″ per year.

<span class="mw-page-title-main">CU Virginis</span> Star in the constellation Virgo

CU Virginis is a single star in the equatorial constellation of Virgo. It has an apparent visual magnitude of 4.99, which is bright enough to be faintly visible to the naked eye. The distance to this star can be estimated from its annual parallax shift of 13.9 mas, yielding a separation of 234 light years.

<span class="mw-page-title-main">Y Centauri</span> Variable star in the constellation Centaurus

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<span class="mw-page-title-main">HD 125248</span> Binary star system in the constellation of Virgo

HD 125248 is a binary star system in the equatorial constellation of Virgo. It has the variable star designation CS Virginis, while HD 125248 is the designation from the Henry Draper Catalogue. This system is dimly visible to the naked eye as a point of light with an apparent visual magnitude that ranges from 5.84 down to 5.95. It is located at a distance of approximately 280 light years from the Sun based on parallax measurements, but is drifting closer with a heliocentric radial velocity of −8 km/s.

<span class="mw-page-title-main">FG Virginis</span> Variable star in the constellation Virgo

FG Virginis is a well-studied variable star in the equatorial constellation of Virgo. It is a dim star, near the lower limit of visibility to the naked eye, with an apparent visual magnitude that ranges from 6.53 down to 6.58. The star is located at a distance of 273.5 light years from the Sun based on parallax measurements, and is drifting further away with a radial velocity of +16 km/s. Because of its position near the ecliptic, it is subject to lunar occultations.

<span class="mw-page-title-main">R Crateris</span> Variable star in the constellation Crater

R Crateris is a star about 700 light years from the Earth in the constellation Crater. It is a semiregular variable star, ranging in brightness from magnitude 8.1 to 9.5 over a period of about 160 days. It is not visible to the naked-eye, but can be seen with a small telescope, or binoculars. R Crateris is a double star; the variable star and its magnitude 9.9 F8V companion are separated by 65.4 arcseconds.

<span class="mw-page-title-main">SW Virginis</span> Star in the constellation Virgo

SW Virginis is a star in the equatorial constellation of Virgo, abbreviated SW Vir. It is a variable star that ranges in brightness from an apparent visual magnitude of 6.65 down to 7.95, with a pulsation period of 153.8 days. The star is located at a distance of approximately 590 light years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of −16 km/s. SW Vir is located near the ecliptic and is subject to lunar occultation, which has allowed its angular diameter to be directly measured.

References

  1. ↑ ASAS All Star Catalogue, The All Sky Automated Survey, retrieved 16 September 2022.
  2. 1 2 3 4 Brown, A. G. A.; et al. (Gaia collaboration) (2021), "Gaia Early Data Release 3: Summary of the contents and survey properties", Astronomy & Astrophysics , 649: A1, arXiv: 2012.01533 , Bibcode:2021A&A...649A...1G, doi: 10.1051/0004-6361/202039657 , S2CID   227254300 (Erratum:  doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  3. 1 2 3 4 Zhang, Bo; et al. (November 2017), "VLBA Trigonometric Parallax Measurement of the Semi-regular Variable RT Vir", The Astrophysical Journal, 849 (2): 99, Bibcode:2017ApJ...849...99Z, doi: 10.3847/1538-4357/aa8ee9 , S2CID   125975009, 99.
  4. 1 2 3 4 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, arXiv: 2011.00294 , Bibcode:2020A&A...644A..45B, doi:10.1051/0004-6361/202039157, A45.
  5. 1 2 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, Bibcode:1942ApJ....96..344J, doi: 10.1086/144469 .
  6. 1 2 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv: 1108.4971 , Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID   119257644.
  7. ↑ Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports , 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID   125853869.
  8. 1 2 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, 206, San Francisco: Astronomical Society of the Pacific: 298, Bibcode:2002IAUS..206..298Y.
  9. 1 2 3 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. 1 2 3 Sharma, Kaushal; et al. (2016), "New atmospheric parameters and spectral interpolator for the MILES cool stars", Astronomy and Astrophysics, 585: A64, arXiv: 1512.04882 , Bibcode:2016A&A...585A..64S, doi:10.1051/0004-6361/201526111, S2CID   118576178.
  11. ↑ "RT Vir", SIMBAD , Centre de données astronomiques de Strasbourg , retrieved 2022-09-07
  12. ↑ Pickering, E. C.; Fleming, W. P. (April 1896), "Harvard College Observatory, circular no. 6. New variable stars", Astrophysical Journal, 3: 296–302, Bibcode:1896ApJ.....3..296P, doi: 10.1086/140219 .
  13. ↑ Cannon, Annie J. (1907). "Second catalogue of variable stars". Annals of Harvard College Observatory. 55: 1–94. Bibcode:1907AnHar..55....1C . Retrieved 16 December 2024.
  14. ↑ 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.
  15. ↑ Dickinson, D. F. (March 1976), "Water emission from infrared stars", Astrophysical Journal Supplement Series, 30: 259–271, Bibcode:1976ApJS...30..259D, doi:10.1086/190362.
  16. 1 2 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, Bibcode:1997A&AS..126..257M, doi: 10.1051/aas:1997263 .
  17. ↑ 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, arXiv: 1301.5872 , Bibcode:2013A&A...551A..72S, doi:10.1051/0004-6361/201220524, S2CID   18675130, A72.
  18. ↑ Yates, J. A.; et al. (2000), Kastner, J. H.; et al. (eds.), "Is the Outflow from RT Vir Bipolar or Rotating?", Asymmetrical Planetary Nebulae II: From Origins to Microstructures, ASP Conference Series, 199: 79, Bibcode:2000ASPC..199...79Y, ISBN   1-58381-026-9.

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