Astronomy:FG Virginis

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Short description: Variable star in the constellation Virgo
FG Virginis
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Visual band light curves for FG Virginis, adapted from Breger et al. (1995)[1]
Observation data
Equinox J2000.0]] (ICRS)
Constellation Virgo
Right ascension  12h 14m 15.457s[2]
Declination −05° 42′ 59.75″[2]
Apparent magnitude (V) 6.56[3] (6.53 to 6.58)[4]
Characteristics
Evolutionary stage Main sequence
Spectral type A8/9V[5]
U−B color index 0.05[6]
B−V color index 0.277±0.007[3]
Variable type δ Sct[4]
Astrometry
Radial velocity (Rv)16.4±0.6[7] km/s
Proper motion (μ) RA: −85.128[2] mas/yr
Dec.: 114.628[2] mas/yr
Parallax (π)11.9261 ± 0.0308[2] mas
Distance273.5 ± 0.7 ly
(83.8 ± 0.2 pc)
Absolute magnitude (MV)2.10[3]
Details
Mass1.80[8] M☉
Radius2.27[9] R☉
Luminosity11.95[3] L☉
Surface gravity (log g)3.9[10] cgs
Temperature7,425[10] K
Rotation1.74±0.43 d[10]
Rotational velocity (v sin i)21.3±1.0[11] km/s
Other designations
FG Vir, BD−04°3235, HD 106384, HIP 59676, SAO 138664, PPM 195288, WDS J12143-0543A[12]
Database references
SIMBADdata

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.[4] The star is located at a distance of 273.5 light years from the Sun based on parallax measurements,[2] and is drifting further away with a radial velocity of +16 km/s.[7] Because of its position near the ecliptic, it is subject to lunar occultations.[13]

The variability of this star was first reported by O. J. Eggen in 1971, who classified it as an ultra-short period cepheid – a proposed category of pulsating stars in the instability strip.[14] It was subsequently grouped in the class of Delta Scuti variables, which show a pulsation period of less than a day.[15] Observations in 1984 by P. Lopez de Coca showed at least one pulsation period with a cycle of 1.9 hours.[16] L. Mantegazza and associates in 1994 were able to detect seven or more pulsation modes, with the previously detected dominant mode being a radial pulsation with a frequency of 12.72 cycles per day.[17]

The star became of interest to astroseismology study because of its relatively slow rotation rate and the numerous modes of pulsation. A multi-site campaign involving the Whole Earth Telescope network was conducted in 1993 to observe this star, which detected ten modes.[1] This was increased to 24 frequencies in 1998,[18] then 67 independent frequencies with 79 total by 2005. Evidence suggests there are many more such modes.[19]

This is an A-type main-sequence star with a stellar classification of A8/9V,[5] but is near the end of its main sequence lifetime.[11] It is classified as a Delta Scuti variable that varies in brightness with an amplitude of 0.040 in visual magnitude and a period of 1.89 hours.[6] Element abundances are similar to the Sun, although there is a slight overabundance of barium and underabundances of sulfur and carbon.[20] It has a projected rotational velocity of 21 km/s, but the actual rotational velocity is likely much higher at around 80 km/s.[11]

References

  1. ↑ 1.0 1.1 Breger, M. et al. (May 1995), "The δ Scuti star FG Virginis. I. Multiple pulsation frequencies determined with a combined DSN/WET campaign", Astronomy & Astrophysics 297: 473, Bibcode: 1995A&A...297..473B. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 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 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A. 
  4. ↑ 4.0 4.1 4.2 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. 
  5. ↑ 5.0 5.1 Houk, N.; Swift, C. (1999), "Michigan catalogue of two-dimensional spectral types for the HD Stars", Michigan Spectral Survey 5, Bibcode: 1999MSS...C05....0H. 
  6. ↑ 6.0 6.1 Rodríguez, E. et al. (June 2000), "A revised catalogue of delta Sct stars", Astronomy & Astrophysics Supplement Series 144 (3): 469–474, doi:10.1051/aas:2000221, Bibcode: 2000A&AS..144..469R. 
  7. ↑ 7.0 7.1 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  8. ↑ Breger, M.; Pamyatnykh, A. A. (May 2006), "Amplitude variability or close frequencies in pulsating stars - the δ Scuti star FG Vir", Monthly Notices of the Royal Astronomical Society 368 (2): 571–578, doi:10.1111/j.1365-2966.2006.10119.x, Bibcode: 2006MNRAS.368..571B. 
  9. ↑ Zima, W. et al. (June 2004), "Moment Method and Pixel-by-Pixel Method: Complementary Mode Identification I. Testing FG Vir-like pulsation modes", Communications in Asteroseismology 144: 5–22, doi:10.1553/cia144s5, Bibcode: 2004CoAst.144....5Z. 
  10. ↑ 10.0 10.1 10.2 Zima, W. et al. (August 2006), "A new method for the spectroscopic identification of stellar non-radial pulsation modes. II. Mode identification of the δ Scuti star FG Virginis", Astronomy & Astrophysics 455 (1): 235–246, doi:10.1051/0004-6361:20064877, Bibcode: 2006A&A...455..235Z. 
  11. ↑ 11.0 11.1 11.2 Breger, M.; Lenz, P. (February 2019), "Photometric data by the Delta Scuti Network. II. EE Cam, FG Vir, 44 Tau", The Journal of Astronomical Data 25 (1): 6, Bibcode: 2019JAD....25....1B. 
  12. ↑ "FG Vir". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=FG+Vir. 
  13. ↑ Eitter, J. J.; Beavers, W. I. (June 1979), "Lunar occultation summary. III", Astrophysical Journal Supplement Series 40: 475–486, doi:10.1086/190595, Bibcode: 1979ApJS...40..475E.  See event no. 528.
  14. ↑ Eggen, O. J. (December 1971), "The Nature of the Blue Stragglers in the Old Disk Population", Publications of the Astronomical Society of the Pacific 83 (496): 762, doi:10.1086/129212, Bibcode: 1971PASP...83..762E. 
  15. ↑ Baglin, A. et al. (March 1973), "Delta Scuti stars", Astronomy & Astrophysics 23: 221, Bibcode: 1973A&A....23..221B. 
  16. ↑ Lopez de Coca, P. et al. (January 1984), "Narrow Band Photometry of FG Vir", Information Bulletin on Variable Stars 2465: 1, Bibcode: 1984IBVS.2465....1L. 
  17. ↑ Mantegazza, L. et al. (July 1994), "Simultaneous intensive photometry and high resolution spectroscopy of δ Scuti stars I. Mode typing of HD 106384 = FG Virginis", Astronomy & Astrophysics 287: 95–104, Bibcode: 1994A&A...287...95M. 
  18. ↑ Breger, M. et al. (January 1999), "The delta Scuti star FG Virginis. IV. Mode identifications and pulsation modelling", Astronomy & Astrophysics 341: 151–162, Bibcode: 1999A&A...341..151B. 
  19. ↑ Breger, M. et al. (June 2005), "Detection of 75+ pulsation frequencies in the δ Scuti star FG Virginis", Astronomy & Astrophysics 435 (3): 955–965, doi:10.1051/0004-6361:20042480, Bibcode: 2005A&A...435..955B. 
  20. ↑ Mittermayer, P.; Weiss, W. W. (September 2003), "Atmospheric properties and abundances of the delta Scuti star FG Virginis", Astronomy & Astrophysics 407 (3): 1097–1101, doi:10.1051/0004-6361:20030930, Bibcode: 2003A&A...407.1097M. 

Further reading

  • Haas, P. (2011), "Analyses of Crawford's uvby β calibrations using the pulsational variations of FG Vir", Communications in Asteroseismology 162: 3, doi:10.1553/cia162s3, Bibcode: 2011CoAst.162....3H. 
  • Lenz, P. et al. (April 2008), "Determination of intrinsic mode amplitudes of the δ Scuti stars FG Vir and 44 Tau", Communications in Asteroseismology 153: 40–48, doi:10.1553/cia_153s40, Bibcode: 2008CoAst.153...40L. 
  • Daszyńska-Daszkiewicz, J. et al. (August 2005), "Inferences from pulsational amplitudes and phases for multimode δ Sct star FG Vir", Astronomy & Astrophysics 438 (2): 653–660, doi:10.1051/0004-6361:20052902, Bibcode: 2005A&A...438..653D. 
  • Kirbiyik, H. et al. (February 2005), "A new oscillating model suggestion for FG Vir", Astrophysics and Space Science 295 (4 7): 473–484, doi:10.1007/s10509-005-1085-y, Bibcode: 2005Ap&SS.295..473K. 
  • Breger, M. et al. (May 2004), "The δ Scuti star FG Vir. V. The 2002 photometric multisite campaign", Astronomy & Astrophysics 419 (2): 695–701, doi:10.1051/0004-6361:20035830, Bibcode: 2004A&A...419..695B. 
  • Mantegazza, L.; Poretti, E. (December 2002), "Line profile variations in the delta Scuti star FG Virginis: A high number of axisymmetric modes", Astronomy & Astrophysics 396 (3): 911–916, doi:10.1051/0004-6361:20021456, Bibcode: 2002A&A...396..911M. 
  • Templeton, Matthew et al. (December 2001), "Asteroseismology of δ Scuti Stars: A Parameter Study and Application to Seismology of FG Virginis", The Astrophysical Journal 563 (2): 999–1012, doi:10.1086/324041, Bibcode: 2001ApJ...563..999T. 
  • Zima, W. (July 2001), "The Spectroscopic and Photometric DSN Campaign 2002 of FG Vir", Communications in Asteroseismology 140: 57–58, Bibcode: 2001CoAst.140...57Z. 
  • Dziembowski, W. A. et al. (November 1998), Kjeldsen, H.; Bedding, T. R., eds., "Oscillations in XX Pyx and FG VIR and the prospects for asteroseismology of delta Scuti stars from space", The First MONS Workshop: Science with a Small Space Telescope, held in Aarhus, Denmark, June 29–30, 1998 (Aarhus Universitet): p. 127, Bibcode: 1998mons.proc..127D. 
  • Viskum, M. et al. (July 1998), "Oscillation mode identifications and models for the delta Scuti star FG Virginis", Astronomy & Astrophysics 335: 549–560, Bibcode: 1998A&A...335..549V. 
  • Breger, M. et al. (March 1998), "The delta Scuti star FG Vir. III. The 1995 multisite campaign and the detection of 24 pulsation frequencies", Astronomy & Astrophysics 331: 271–279, Bibcode: 1998A&A...331..271B. 
  • Stankov, A.; Zima, W. (March 1998), "Photometry of the Delta Scuti Star FG VIR during the 1995 Multi-Site Campaign", Baltic Astronomy 7 (2): 243–253, doi:10.1515/astro-1998-0207, Bibcode: 1998BaltA...7..243S. 
  • Breger, M. et al. (May 1996), "The δ Scuti star FG Virginis. II. A search for high pulsation frequencies", Astronomy & Astrophysics 309: 197–202, Bibcode: 1996A&A...309..197B. 
  • Guzik, J. A.; Bradley, P. A. (September 1995), "Models and mode identifications of the Delta Scuti Star FG Vir", Delta Scuti Star Newsletter 9 (9): 7–14, Bibcode: 1995DSSN....9....7G. 
  • Breger, M. (September 1995), "The 1995 FG VIR campaign: will 550 hours of new data and 19 frequencies be enough to do asteroseismology?", Delta Scuti Star Newsletter 9 (9): 14–17, Bibcode: 1995DSSN....9...14B. 
  • Dawson, D. W. et al. (June 1995), "A Photometric Study of the delta Scuti Star FG Virginis Undertaken during 1985/6", Publications of the Astronomical Society of the Pacific 107: 517–520, doi:10.1086/133585, Bibcode: 1995PASP..107..517D. 
  • Dawson, D. W. (March 1990), "The Period Structure of FG Virginis", Bulletin of the American Astronomical Society 22: 831, Bibcode: 1990BAAS...22..831D. 
  • Gonzalez-Bedolla, S. F.; Rodriguez, E. (February 1990), "FG Vir, Additional Photoelectric Observations", Information Bulletin on Variable Stars 3426: 1, Bibcode: 1990IBVS.3426....1G. 



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