Astronomy:XX Virginis
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Virgo |
| Right ascension | 14h 16m 48.593s[1] |
| Declination | −06° 17′ 15.06″[1] |
| Apparent magnitude (V) | 11.55 to 12.78[2] |
| Characteristics | |
| Spectral type | kA7hF6[3] |
| Variable type | Anomalous Cepheid[3] |
| Astrometry | |
| Radial velocity (Rv) | −55.0[4] km/s |
| Proper motion (μ) | RA: −11.421[1] mas/yr Dec.: −10.826[1] mas/yr |
| Parallax (π) | 0.144 ± 0.0194[1] mas |
| Distance | 9,360 ± 1,100 ly (2,869±337[5] pc) |
| Absolute magnitude (MV) | −0.74[6] |
| Details | |
| Mass | 0.6[6] M☉ |
| Radius | 13±7[7] R☉ |
| Luminosity | 156[1] L☉ |
| Surface gravity (log g) | 1.95 (avg)[8] cgs |
| Temperature | 6,410 K (6,030 to 7,610)[8] K |
| Metallicity [Fe/H] | −1.57[9] dex |
| Age | 293[1] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
XX Virginis is a variable star in the equatorial constellation of Virgo, abbreviated XX Vir. It ranges in apparent visual magnitude from 11.55 to 12.78,[2] which is much too faint to be visible to the naked eye. The star is located at an estimated distance of roughly 9,400 light-years (2,900 pc).[5]
This is classified as a type II Cepheid of the BL Her type,[11] having a short pulsation period of 1.348 days.[2] However, a 2014 survey has it classified as an anomalous Cepheid of the BL Boo type.[12] The light curve is asymmetrical, resembling that of a type ab RR Lyrae variable. On the HR diagram it is positioned above the horizontal branch. For this reason, it is sometimes used as the prototype of, "Above Horizontal Branch variables of subtype 1."[13]
This is a very metal-poor star[8] with an estimated 0.6 times the mass of the Sun. The effective temperature and radius vary depending on the phase of the pulsation cycle.[6]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940. Gaia DR3 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 Yacob, Alemiye M. et al. (October 2022), "A search for period changes of eight short-period Type II Cepheids", Monthly Notices of the Royal Astronomical Society 516 (2): 2095–2111, doi:10.1093/mnras/stac2167, Bibcode: 2022MNRAS.516.2095Y.
- ↑ 3.0 3.1 "XX Vir". AAVSO. https://vsx.aavso.org/index.php?view=detail.top&oid=37857.
- ↑ Duflot, M. et al. (1995), "Radial velocities: The Wilson-Evans-Batten catalogue", Astronomy and Astrophysics Supplement Series 114: 269, Bibcode: 1995A&AS..114..269D.
- ↑ 5.0 5.1 Stassun, Keivan G. (2019), "The Revised TESS Input Catalog and Candidate Target List", The Astronomical Journal 158 (4): 138, doi:10.3847/1538-3881/ab3467, Bibcode: 2019AJ....158..138S.
- ↑ 6.0 6.1 6.2 "The absolute magnitude of the field population. II. Cepheid XX Virginis", Astronomical Journal 84: 1840–1845, December 1979, doi:10.1086/112615, Bibcode: 1979AJ.....84.1840W.
- ↑ Balog, Z. et al. (May 1997), "Baade-Wesselink Radius Determination of Type II Cepheids", Astronomical Journal 113: 1833, doi:10.1086/118394, Bibcode: 1997AJ....113.1833B.
- ↑ 8.0 8.1 8.2 "A Photometric Study of XX Virginis and V716 Ophiuchi", Publications of the Astronomical Society of the Pacific 106: 472, May 1994, doi:10.1086/133402, Bibcode: 1994PASP..106..472M.
- ↑ Wallerstein, George; Farrell, Elizabeth M. (December 2018), "Kinematics of Type II Cepheids of the Galactic Halo", The Astronomical Journal 156 (6): id. 299, doi:10.3847/1538-3881/aaee6d, Bibcode: 2018AJ....156..299W.
- ↑ "U Peg". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=U+Peg.
- ↑ Smith, Horace A. et al. (August 1978), "Strömgren photometry of field BL Herculis stars. I. BL Herculis and XX Virginis", Publications of the Astronomical Society of the Pacific 90: 422–428, doi:10.1086/130351, Bibcode: 1978PASP...90..422S.
- ↑ Drake, A. J. et al. (2014), "The Catalina Surveys Periodic Variable Star Catalog", The Astrophysical Journal Supplement Series 213 (1): 9, doi:10.1088/0067-0049/213/1/9, Bibcode: 2014ApJS..213....9D.
- ↑ Jayasinghe, T. et al. (July 2018), "The ASAS-SN catalogue of variable stars I: The Serendipitous Survey", Monthly Notices of the Royal Astronomical Society 477 (3): 3145–3163, doi:10.1093/mnras/sty838, Bibcode: 2018MNRAS.477.3145J.
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