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] 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  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]

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. Based upon parallax measurements, it is located at a distance of about 198 light-years from the Sun.

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

Beta Virginis, a name Latinised from β Virginis, is a star in the equatorial constellation of Virgo. It has the proper name Zavijava, and, despite its designation 'beta', is the fifth-brightest star in Virgo with an apparent visual magnitude of 3.604. The distance to this star is 35.7 light-years based on parallax, and it is drifting further away with a radial velocity of +4.1 km/s. It is 0.69 of a degree north of the ecliptic, so it can be occulted by the Moon and (rarely) by planets. The next planetary occultation of Beta Virginis will take place on 11 August 2069, by Venus.

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

Zeta Virginis is a binary star in the zodiac constellation of Virgo. It is visible to the naked eye with an apparent visual magnitude of +3.376 and is located about a half degree south of the celestial equator. Based on parallax measurements obtained during the Hipparcos mission, it is about 74 light-years distant from the Sun.

<span class="mw-page-title-main">Iota Virginis</span> Binary star system in the constellation Virgo

Iota Virginis is a binary star in the constellation of Virgo. Its apparent magnitude is 4.08. Based on its parallax, it is assumed to be relatively nearby, at 72.5 light-years.

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

ν Virginis, Latinized as Nu Virginis, is a single star in the zodiac constellation of Virgo, located at the western tip of the classic constellation and nearly due south of the prominent star Denebola. It is a red-hued star with an apparent visual magnitude of 4.04 and can be seen with the naked eye. Because the star lies near the ecliptic it is subject to occultations by the Moon. Parallax measurements provide an estimated distance of around 294 light years from the Sun, and it is drifting further away with a radial velocity of +50 km/s.

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

Omicron Virginis is a star in the zodiac constellation of Virgo. It is visible to the naked eye with an apparent visual magnitude of +4.12. Based upon parallax measurements, it is about 163 light years from the Sun.

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

Tau Virginis is a single star in the zodiac constellation Virgo. With an apparent visual magnitude of 4.28, it is faintly visible to the naked eye. The distance to Tau Virginis, based upon parallax measurements, is approximately 225 light years with a margin of error of ±3 light years.

109 Virginis is a single, white-hued star in the zodiac constellation of Virgo, located some 134.5 light years away from the Sun. It is the seventh-brightest member of this constellation, having an apparent visual magnitude of +3.72.

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

Pi Virginis is a binary star in the zodiac constellation of Virgo. It is visible to the naked eye with an apparent visual magnitude of 4.64. The distance to this star, based upon parallax measurements, is roughly 380 light years.

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

Omega Virginis is a solitary star in the zodiac constellation Virgo. It has an apparent visual magnitude of +5.2, which is bright enough to be faintly visible to the naked eye. Based upon an annual stellar parallax shift of 6.56 milliarcseconds, it is located about 500 light years from the Sun.

VX Sagittarii is an extreme asymptotic giant branch star located more than 1.5 kiloparsec away from the Sun in the constellation of Sagittarius. It is a pulsating variable star with an unusually large magnitude range. It is also one of the largest stars discovered so far, with a radius varying between 1,350 and 1,940 solar radii (940,000,000 and 1.35×109 km; 6.3 and 9.0 au). It is the most luminous known AGB star, at bolometric magnitude –8.6, which is even brighter than the theoretical limit at –8.0.

69 Virginis is a single star in the zodiac constellation of Virgo, located about 259 light years away. It is visible to the naked eye as a faint orange-hued star with an apparent visual magnitude of 4.76, although it is a suspected variable that may range in magnitude from 4.75 down to 4.79. This object is moving closer to the Earth with a heliocentric radial velocity of −13 km/s. The light from this star is polarized due to intervening interstellar dust.

<span class="mw-page-title-main">ET Virginis</span> Evolved red giant star in the constellation Virgo

ET Virginis is a single, red-hued star in the equatorial constellation of Virgo. It can be viewed with the naked eye, having an apparent visual magnitude of 4.91. Based upon an annual parallax shift of 5.9 mas, it is located 560 light years away. It is moving further from the Earth with a heliocentric radial velocity of +18.6 km/s, having come within 177 ly of the Sun around 6.3 million years ago.

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<span class="mw-page-title-main">CU Virginis</span> Ap 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

Y Centauri or Y Cen is a semiregular variable star in the constellation of Centaurus.

<span class="mw-page-title-main">AH Scorpii</span> Star in the constellation Scorpius

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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.

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, San Francisco: Astronomical Society of the Pacific, 206: 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. ↑ 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, Bibcode:1976ApJS...30..259D, doi:10.1086/190362.
  15. 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 .
  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, arXiv: 1301.5872 , Bibcode:2013A&A...551A..72S, doi:10.1051/0004-6361/201220524, S2CID   18675130, A72.
  17. ↑ 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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