Astronomy:16 Virginis
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Virgo |
| Right ascension | 12h 20m 20.98133s[1] |
| Declination | +03° 18′ 45.2604″[1] |
| Apparent magnitude (V) | 4.96[2] |
| Characteristics | |
| Spectral type | K0.5 IIIb Fe−0.5[3] |
| B−V color index | 1.16[2] |
| Astrometry | |
| Radial velocity (Rv) | +36.66±0.17[4] km/s |
| Proper motion (μ) | RA: −292.95[1] mas/yr Dec.: −63.58[1] mas/yr |
| Parallax (π) | 10.59 ± 0.25[1] mas |
| Distance | 308 ± 7 ly (94 ± 2 pc) |
| Absolute magnitude (MV) | 0.26[5] |
| Details | |
| Mass | 1.62[2] M☉ |
| Radius | 18[6] R☉ |
| Luminosity | 131.8[2] L☉ |
| Surface gravity (log g) | 2.20[7] cgs |
| Temperature | 4,423±32[2] K |
| Metallicity [Fe/H] | −0.33[7] dex |
| Age | 3.22[2] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
16 Virginis is a single[9] star in the zodiac constellation of Virgo, located about 308[1] 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.[2] This is an IAU radial velocity standard star;[10] it is moving further from the Earth with a heliocentric radial velocity of +37 km/s.[4] The star has a relatively high proper motion, traversing the celestial sphere at an angular rate of 0.301″ per year.[11]
In Chinese astronomy, 16 Virginis is called 謁者, Pinyin: Yèzhě, meaning Usher to the Court, because this star is marking itself and stand alone in Usher to the Court asterism, Supreme Palace enclosure mansion (see : Chinese constellation).[12]
This is an evolved K-type giant star with a stellar classification of K0.5 IIIb Fe−0.5,[3] where the suffix notation denotes a mild underabundance of iron in the spectrum. It is a red clump giant, which indicates is on the horizontal branch generating energy via helium fusion at its core.[13] The interferometry-measured angular diameter of this star, after correcting for limb darkening, is 1.74±0.02 mas,[14] which, at its estimated distance, equates to a physical radius of about 18 times the radius of the Sun.[6] It is about three[2] billion years old with 1.62[2] times the mass of the Sun and is radiating 132[2] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,423 K.[2]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V.
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", Astronomical Journal 150 (3): 88, doi:10.1088/0004-6256/150/3/88, Bibcode: 2015AJ....150...88L.
- ↑ 3.0 3.1 Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series 71: 245, doi:10.1086/191373, Bibcode: 1989ApJS...71..245K.
- ↑ 4.0 4.1 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.
- ↑ Cardini, D. (January 2005), "Mg II chromospheric radiative loss rates in cool active and quiet stars", Astronomy and Astrophysics 430: 303–311, doi:10.1051/0004-6361:20041440, Bibcode: 2005A&A...430..303C.
- ↑ 6.0 6.1 Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1, https://books.google.com/books?id=OvTjLcQ4MCQC&pg=PA41. The radius (R*) is given by:
- [math]\displaystyle{ \begin{align} 2\cdot R_* & = \frac{(10^{-3}\cdot 94.4\cdot 1.74)\ \text{AU}}{0.0046491\ \text{AU}/R_{\bigodot}} \\ & \approx 35.3\cdot R_{\bigodot} \end{align} }[/math]
- ↑ 7.0 7.1 Jofré, P. et al. (2014), "Gaia FGK benchmark stars: Metallicity", Astronomy and Astrophysics 564: A133, doi:10.1051/0004-6361/201322440, Bibcode: 2014A&A...564A.133J.
- ↑ "c Vir". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=c+Vir.
- ↑ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869–879, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ Batten, A. H.; Crampton, D.; Fletcher, J. M.; Morbey, C. L. (1971), "Wavelength Standards for the Measurement of Radial Velocities", Publications of the Dominion Astrophysical Observatory 13: 441, Bibcode: 1971PDAO...13..441B.
- ↑ Lépine, Sébastien; Shara, Michael M. (March 2005), "A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog)", The Astronomical Journal 129 (3): 1483–1522, doi:10.1086/427854, Bibcode: 2005AJ....129.1483L.
- ↑ Ridpath, Ian, "Virgo the Virgin", Startales, http://www.ianridpath.com/startales/virgo.htm.
- ↑ Alves, David R. (August 2000), "K-Band Calibration of the Red Clump Luminosity", The Astrophysical Journal 539 (2): 732–741, doi:10.1086/309278, Bibcode: 2000ApJ...539..732A.
- ↑ Richichi, A.; Percheron, I.; Khristoforova, M. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics 431 (2): 773–777, doi:10.1051/0004-6361:20042039, Bibcode: 2005A&A...431..773R.
Horizontal-branch stars
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