Astronomy:Omicron Geminorum
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Gemini |
| Right ascension | 07h 39m 09.93286s[1] |
| Declination | +34° 35′ 03.6443″[1] |
| Apparent magnitude (V) | 4.90[2] |
| Characteristics | |
| Spectral type | F3 III[3] |
| U−B color index | +0.09[2] |
| B−V color index | +0.41[2] |
| Astrometry | |
| Radial velocity (Rv) | +7.3[4] km/s |
| Proper motion (μ) | RA: -33.42[1] mas/yr Dec.: -118.17[1] mas/yr |
| Parallax (π) | 19.61 ± 0.30[1] mas |
| Distance | 166 ± 3 ly (51.0 ± 0.8 pc) |
| Absolute magnitude (MV) | 1.35[5] |
| Details | |
| Radius | 3.7[6] R☉ |
| Luminosity | 24[7] L☉ |
| Surface gravity (log g) | 3.56[8] cgs |
| Temperature | 6,309[7] K |
| Metallicity [Fe/H] | +0.12[5] dex |
| Rotational velocity (v sin i) | 91.1[8] km/s |
| Age | 1[5] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Omicron Geminorum (ο Geminorum, abbreviated Omicron Gem, ο Gem), also named Jishui,[10] is a solitary[11] star in the constellation of Gemini. It is faintly visible to the naked eye with an apparent visual magnitude of 4.90.[2] Based upon an annual parallax shift of 19.61 mas,[1] it is located at a distance of 166 light-years from the Sun.
Nomenclature
ο Geminorum (Latinised to Omicron Geminorum) is the star's Bayer designation.
The star bore the traditional Chinese name of Jishui.[12] In 2016, the IAU organized a Working Group on Star Names (WGSN)[13] to catalog and standardize proper names for stars. The WGSN approved the name Jishui for this star on 30 June 2017 and it is now so included in the List of IAU-approved Star Names.[10]
It was also known to be part of a much bigger constellation named Telescopium Herschelii before it was unrecognized by the International Astronomical Union (IAU).
Properties
This is an F-type giant star[8] with a stellar classification of F3 III.[3] The measured angular diameter is 0.68±0.03 mas,[14] which, at its estimated distance, yields a physical size of about 3.7 times the radius of the Sun.[6] It radiates approximately 24 times the solar luminosity from an outer atmosphere at an effective temperature of 6,309 K.[7]
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.
- ↑ 2.0 2.1 2.2 2.3 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data (SIMBAD), Bibcode: 1986EgUBV........0M.
- ↑ 3.0 3.1 Eggen, O. J. (1962), "Space-velocity vectors for 3483 stars with proper motion and radial velocity", Royal Observatory Bulletin 51: 79, Bibcode: 1962RGOB...51...79E.
- ↑ Wielen, R. et al. (2000), "Sixth Catalogue of Fundamental Stars (FK6). Part III. Additional fundamental stars with direct solutions", Veröffentlichungen Astronomisches Rechen-Institut Heidelberg (Karlsruhe: Verlag G. Braun) 37 (37): pp. 1–308, ISBN 3-7650-0536-3, Bibcode: 2000VeARI..37....1W.
- ↑ 5.0 5.1 5.2 Holmberg, J. et al. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics 501 (3): 941–947, doi:10.1051/0004-6361/200811191, Bibcode: 2009A&A...501..941H.
- ↑ 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{(51.0\cdot 0.68\cdot 10^{-3})\ \text{AU}}{0.0046491\ \text{AU}/R_{\bigodot}} \\ & \approx 7.46\cdot R_{\bigodot} \end{align} }[/math]
- ↑ 7.0 7.1 7.2 McDonald, I. et al. (2012). "Fundamental Parameters and Infrared Excesses of Hipparcos Stars". Monthly Notices of the Royal Astronomical Society 427 (1): 343–57. doi:10.1111/j.1365-2966.2012.21873.x. Bibcode: 2012MNRAS.427..343M.
- ↑ 8.0 8.1 8.2 Schröder, C.; Reiners, Ansgar; Schmitt, Jürgen H. M. M. (January 2009), "Ca II HK emission in rapidly rotating stars. Evidence for an onset of the solar-type dynamo", Astronomy and Astrophysics 493 (3): 1099–1107, doi:10.1051/0004-6361:200810377, Bibcode: 2009A&A...493.1099S, http://goedoc.uni-goettingen.de/goescholar/bitstream/handle/1/9690/aa10377-08.pdf?sequence=2[yes|permanent dead link|dead link}}]
- ↑ "* omi Gem". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+omi+Gem.
- ↑ 10.0 10.1 "Naming Stars". IAU.org. https://www.iau.org/public/themes/naming_stars/.
- ↑ 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.
- ↑ "WG Triennial Report (2015-2018) - Star Names". p. 7. https://www.iau.org/static/science/scientific_bodies/working_groups/280/wg-starnames-triennial-report-2015-2018.pdf.
- ↑ "IAU Working Group on Star Names (WGSN)". https://www.iau.org/science/scientific_bodies/working_groups/280/.
- ↑ Richichi, A. et al. (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.
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