Zeta Virginis
 Location of ζ Virginis (circled) |
|
| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Virgo |
| Right ascension | 13h 34m 41.59115s[1] |
| Declination | –0° 35′ 44.9487″[1] |
| Apparent magnitude (V) | +3.376[2] |
| Characteristics | |
| Spectral type | A3 V[3] |
| U−B color index | +0.141[2] |
| B−V color index | +0.114[2] |
| Astrometry | |
| Radial velocity (Rv) | –13.2[4] km/s |
| Proper motion (μ) | RA: –280.48[1] mas/yr Dec.: +49.05[1] mas/yr |
| Parallax (π) | 44.03 ± 0.19[1] mas |
| Distance | 74.1 ± 0.3 ly (22.71 ± 0.10 pc) |
| Absolute magnitude (MV) | 1.64 ± 0.05[5] |
| Details | |
| ζ Vir A | |
| Mass | 2.041 ± 0.024[5] M☉ |
| Radius | 2.079 ± 0.025[6] R☉ |
| Luminosity | 17.885 ± 0.252[6] L☉ |
| Surface gravity (log g) | 4.12[7] |
| Temperature | 8,247 ± 52[6] K |
| Rotational velocity (v sin i) | 222[8] km/s |
| Age | 0.51[9] Gyr |
| ζ Vir B | |
| Mass | 0.168+0.012 −0.016[5] M☉ |
| Other designations | |
Zeta Virginis (ζ Vir, ζ Virginis) is a star in the zodiac constellation of Virgo. It has the traditional name Heze, which is not often used and of unclear origin. The star is known as Horn 2 (角宿二) in Chinese astronomy.[citation needed] It is visible to the naked eye with has an apparent visual magnitude is +3.376[2] and is located about a half degree south of the celestial equator at a distance of 74.1 light-years (22.7 parsecs) from Earth.[1]
ζ Virginis is a main sequence star with a spectral class A3 V,[3] indicating that it is generating energy through the nuclear fusion of hydrogen at its core. This energy is being radiated from its outer envelope at an effective temperature of 8,247 K,[6] giving Zeta Virginis the white hue of an A-type star.[10] It has twice the mass and double the radius of the Sun and is about a half billion years old.[5][9][6]
In 2010, a low mass stellar companion was discovered, ζ Virginis B. The object has not been under observation for a sufficient length of time to determine accurate orbital elements. However, the pair are estimated to be orbiting at an average separation of at least 24.9 Astronomical Units and an orbital eccentricity of 0.16 or more. Their orbital period is a minimum of 124 years. This companion may be a red dwarf star, which would explain the observed X-ray flux from this system.[5]
[edit] References
- ^ a b c d e f van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, Bibcode 2007A&A...474..653V, doi:10.1051/0004-6361:20078357
- ^ a b c d Gutierrez-Moreno, Adelina et al. (1966), A System of photometric standards, 1, Publicaciones Universidad de Chile, Department de Astronomy, pp. 1–17, Bibcode 1966PDAUC...1....1G
- ^ a b Levato, O. H. (August 1972), "Rotational Velocities and Spectral Types of Some A-Type Stars", Publications of the Astronomical Society of the Pacific 84 (500): 584, Bibcode 1972PASP...84..584L, doi:10.1086/129336
- ^ Wielen, R. et al. (1999), Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions, Astronomisches Rechen-Institut Heidelberg, Bibcode 1999VeARI..35....1W
- ^ a b c d e Hinkley, Sasha et al. (March 2010), "Discovery and Characterization of a Faint Stellar Companion to the A3V Star ζ Virginis", The Astrophysical Journal 712 (1): 421–428, Bibcode 2010ApJ...712..421H, doi:10.1088/0004-637X/712/1/421
- ^ a b c d e Boyajian, Tabetha S. et al. (February 2012), "Stellar Diameters and Temperatures. I. Main-sequence A, F, and G Stars", The Astrophysical Journal 746 (1): 101, Bibcode 2012ApJ...746..101B, doi:10.1088/0004-637X/746/1/101. See Table 10.
- ^ Erspamer, D.; North, P. (February 2003), "Automated spectroscopic abundances of A and F-type stars using echelle spectrographs. II. Abundances of 140 A-F stars from ELODIE", Astronomy and Astrophysics 398: 1121–1135, arXiv:astro-ph/0210065, Bibcode 2003A&A...398.1121E, doi:10.1051/0004-6361:20021711
- ^ Royer, F.; Zorec, J.; Gómez, A. E. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics 463 (2): 671–682, arXiv:astro-ph/0610785, Bibcode 2007A&A...463..671R, doi:10.1051/0004-6361:20065224
- ^ a b Su, K. Y. L. et al. (December 2006), "Debris Disk Evolution around A Stars", The Astrophysical Journal 653 (1): 675–689, arXiv:astro-ph/0608563, Bibcode 2006ApJ...653..675S, doi:10.1086/508649
- ^ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html, retrieved 2012-01-16
[edit] External links
- Kaler, James B., "HEZE (Zeta Virginis)", Stars (University of Illinois), http://stars.astro.illinois.edu/sow/heze.html, retrieved 2012-02-01
