Astronomy:Zeta2 Scorpii
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Scorpius |
| Right ascension | 16h 54m 35.00503s[1] |
| Declination | −42° 21′ 40.7370″[1] |
| Apparent magnitude (V) | 3.59 to 3.65[2] |
| Characteristics | |
| Evolutionary stage | red giant branch[3] |
| Spectral type | K4 III[4] |
| U−B color index | +1.65[5] |
| B−V color index | +1.37[5] |
| R−I color index | +0.68[5] |
| Astrometry | |
| Radial velocity (Rv) | −18.70±0.06[6] km/s |
| Proper motion (μ) | RA: −126.721[1] mas/yr Dec.: −228.837[1] mas/yr |
| Parallax (π) | 24.2353 ± 0.1985[1] mas |
| Distance | 135 ± 1 ly (41.3 ± 0.3 pc) |
| Absolute magnitude (MV) | 0.30±0.09[7] |
| Details[8] | |
| Mass | 1.18±0.15 M☉ |
| Radius | 18.7±1.0 R☉ |
| Luminosity | 130±20 L☉ |
| Surface gravity (log g) | 2.10±0.07 cgs |
| Temperature | 4,286±49 K |
| Metallicity [Fe/H] | −0.10±0.11 dex |
| Rotational velocity (v sin i) | 2.30±0.45 km/s |
| Age | 6.0±2.6 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Zeta2 Scorpii (Zeta2 Sco, ζ2 Scorpii, ζ2 Sco) is a star in the constellation of Scorpius. With an apparent visual magnitude variying s between 3.59 and 3.65, this star is visible to the naked eye. Parallax measurements derive a distance of 135 light-years to the star.[1]
The spectrum of this star matches a spectral class of K4 III,[4] with the luminosity class "III" classifying it as a giant star that has exhausted all the hydrogen at its core and has expanded. Around six billion years old, this 1.18-solar mass star has swollen to 18.7 solar diameters and now radiates 130 times the Sun's luminosity from its photosphere. The effective temperature of the star has cooled to 4,286 K,[8] giving it the orangish hue typical of a K-type star.[10]
Zeta2 is located near the blue-white supergiant star ζ1 Scorpii in Earth's sky. In astronomical terms, ζ2 is much closer to the Sun and unrelated to ζ1 except for line-of sight co-incidence. ζ1 is about 6,000 light-years away and probably an outlying member of open star cluster NGC 6231 (also known as the "northern jewel box" cluster). ζ2 can also be distinguished from its optical partner, ζ1, because of its orangish colour especially in long-exposure astrophotographs.
References
- ↑ 1.0 1.1 1.2 1.3 1.4 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.
- ↑ NSV 8028, database entry, New Catalogue of Suspected Variable Stars, the improved version, Sternberg Astronomical Institute, Moscow, Russia. Accessed on line November 20, 2009.
- ↑ Setiawan, J.; Pasquini, L.; Da Silva, L.; Hatzes, A. P.; von Der Lühe, O.; Girardi, L.; De Medeiros, J. R.; Guenther, E. (2004). "Precise radial velocity measurements of G and K giants. Multiple systems and variability trend along the Red Giant Branch". Astronomy and Astrophysics 421: 241. doi:10.1051/0004-6361:20041042-1. Bibcode: 2004A&A...421..241S.
- ↑ 4.0 4.1 Landi Dessy, J.; Keenan, P. C. (November 1966), "Spectral Types on the MK System for Forty-Three Bright Southern Stars, K2-M6", Astrophysical Journal 146: 587, doi:10.1086/148925, Bibcode: 1966ApJ...146..587L.
- ↑ 5.0 5.1 5.2 HR 6271, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line November 20, 2009.
- ↑ Evans, D. S. (June 20–24, 1966), Batten, Alan Henry; Heard, John Frederick, eds., "The Revision of the General Catalogue of Radial Velocities", Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30 (University of Toronto: International Astronomical Union) 30: p. 57, Bibcode: 1967IAUS...30...57E.
- ↑ da Silva, L. et al. (November 2006), "Basic physical parameters of a selected sample of evolved stars", Astronomy and Astrophysics 458 (2): 609–623, doi:10.1051/0004-6361:20065105, Bibcode: 2006A&A...458..609D.
- ↑ 8.0 8.1 Jofré, E. et al. (2015). "Stellar parameters and chemical abundances of 223 evolved stars with and without planets". Astronomy & Astrophysics 574: A50. doi:10.1051/0004-6361/201424474. A50. Bibcode: 2015A&A...574A..50J. ζ2 Sco' database entry at VizieR.
- ↑ "zet02 Sco". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=zet02+Sco.
- ↑ "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.
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