FG Virginis
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| 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 mas/yr[2] Dec.: 114.628 mas/yr[2] |
| Parallax (π) | 11.9261 ± 0.0308 mas[2] |
| Distance | 273.5 ± 0.7 ly (83.8 ± 0.2 pc) |
| Absolute magnitude (MV) | 2.10[3] |
| Details | |
| Mass | 1.80[8] M☉ |
| Radius | 2.27[9] R☉ |
| Luminosity | 11.95[3] L☉ |
| Surface gravity (log g) | 3.9[10] cgs |
| Temperature | 7,425[10] K |
| Rotation | 1.74±0.43 d[10] |
| Rotational velocity (v sin i) | 21.3±1.0[11] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
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[edit]
- ^ a b 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.
- ^ a b c d e 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.
- ^ a b c d 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.
- ^ a b c 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.
- ^ a b Houk, N.; Swift, C. (1999), "Michigan catalogue of two-dimensional spectral types for the HD Stars", Michigan Spectral Survey, 5, Bibcode:1999MSS...C05....0H.
- ^ a b Rodríguez, E.; et al. (June 2000), "A revised catalogue of delta Sct stars", Astronomy & Astrophysics Supplement Series, 144 (3): 469–474, Bibcode:2000A&AS..144..469R, doi:10.1051/aas:2000221, hdl:10261/226673.
- ^ a b Brown, A. G. A.; et al. (Gaia collaboration) (August 2018), "Gaia Data Release 2: Summary of the contents and survey properties", Astronomy & Astrophysics, 616, A1, arXiv:1804.09365, Bibcode:2018A&A...616A...1G, doi:10.1051/0004-6361/201833051 Gaia DR2 record for this source at VizieR.
- ^ 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, arXiv:astro-ph/0602037, Bibcode:2006MNRAS.368..571B, doi:10.1111/j.1365-2966.2006.10119.x, S2CID 18429588.
- ^ 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, Bibcode:2004CoAst.144....5Z, doi:10.1553/cia144s5.
- ^ a b c 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, arXiv:astro-ph/0606515, Bibcode:2006A&A...455..235Z, doi:10.1051/0004-6361:20064877, S2CID 54036626.
- ^ a b c 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.
- ^ "FG Vir", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2022-06-14.
- ^ Eitter, J. J.; Beavers, W. I. (June 1979), "Lunar occultation summary. III", Astrophysical Journal Supplement Series, 40: 475–486, Bibcode:1979ApJS...40..475E, doi:10.1086/190595. See event no. 528.
- ^ 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, Bibcode:1971PASP...83..762E, doi:10.1086/129212, S2CID 120025134.
- ^ Baglin, A.; et al. (March 1973), "Delta Scuti stars", Astronomy & Astrophysics, 23: 221, Bibcode:1973A&A....23..221B.
- ^ 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.
- ^ 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.
- ^ Breger, M.; et al. (January 1999), "The delta Scuti star FG Virginis. IV. Mode identifications and pulsation modelling", Astronomy & Astrophysics, 341: 151–162, arXiv:astro-ph/9811338, Bibcode:1999A&A...341..151B.
- ^ Breger, M.; et al. (June 2005), "Detection of 75+ pulsation frequencies in the δ Scuti star FG Virginis", Astronomy & Astrophysics, 435 (3): 955–965, arXiv:astro-ph/0502073, Bibcode:2005A&A...435..955B, doi:10.1051/0004-6361:20042480, S2CID 119042031.
- ^ Mittermayer, P.; Weiss, W. W. (September 2003), "Atmospheric properties and abundances of the delta Scuti star FG Virginis", Astronomy & Astrophysics, 407: 1097–1101, Bibcode:2003A&A...407.1097M, doi:10.1051/0004-6361:20030930, S2CID 123022971.
Further reading[edit]
- Haas, P. (2011), "Analyses of Crawford's uvby β calibrations using the pulsational variations of FG Vir", Communications in Asteroseismology, 162: 3, Bibcode:2011CoAst.162....3H, doi:10.1553/cia162s3.
- 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, Bibcode:2008CoAst.153...40L, doi:10.1553/cia_153s40.
- 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, arXiv:astro-ph/0504177, Bibcode:2005A&A...438..653D, doi:10.1051/0004-6361:20052902, S2CID 119384957.
- Kirbiyik, H.; et al. (February 2005), "A new oscillating model suggestion for FG Vir", Astrophysics and Space Science, 295 (4 7): 473–484, Bibcode:2005Ap&SS.295..473K, doi:10.1007/s10509-005-1085-y, S2CID 121788461.
- Breger, M.; et al. (May 2004), "The δ Scuti star FG Vir. V. The 2002 photometric multisite campaign", Astronomy & Astrophysics, 419 (2): 695–701, arXiv:astro-ph/0404161, Bibcode:2004A&A...419..695B, doi:10.1051/0004-6361:20035830, S2CID 119519055.
- 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, arXiv:astro-ph/9905326, Bibcode:2002A&A...396..911M, doi:10.1051/0004-6361:20021456, S2CID 118962688.
- 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, arXiv:astro-ph/0108458, Bibcode:2001ApJ...563..999T, doi:10.1086/324041, S2CID 119387461.
- 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, arXiv:astro-ph/9804218, 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, Bibcode:1998BaltA...7..243S, doi:10.1515/astro-1998-0207, S2CID 117560195.
- 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, Bibcode:1995PASP..107..517D, doi:10.1086/133585, S2CID 123547347.
- 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.
