Astronomy:Alpha Horologii
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Horologium |
| Right ascension | 04h 14m 00.114s[1] |
| Declination | −42° 17′ 39.73″[1] |
| Apparent magnitude (V) | +3.846[2] |
| Characteristics | |
| Evolutionary stage | Giant star |
| Spectral type | K2 III[3] |
| U−B color index | +1.013[4] |
| B−V color index | 1.083±0.037[2] |
| Astrometry | |
| Radial velocity (Rv) | +21.6±0.3[5] km/s |
| Proper motion (μ) | RA: +41.992±0.125[1] mas/yr Dec.: −203.157±0.154[1] mas/yr |
| Parallax (π) | 27.721 ± 0.11195[1] mas |
| Distance | 117.6+0.55 −0.52 ly (36.06+0.17 −0.16 pc) |
| Absolute bolometric magnitude (Mbol) | +1.08[6] |
| Details[2] | |
| Mass | 1.409±0.265 M☉ |
| Radius | 9.931±0.351 R☉ |
| Luminosity | 37.61[7] L☉ |
| Surface gravity (log g) | 2.82±0.02 cgs |
| Temperature | 4695±50 K |
| Metallicity [Fe/H] | −0.03±0.03 dex |
| Age | 3.561±2.333 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Alpha Horologii (α Horologii) is a solitary[9] orange-hued giant star and the brightest star in the constellation Horologium. It is visible to the naked eye with an apparent visual magnitude of +3.85.[2] Based upon an parallax shift of 27.721 mas as seen from the Earth, it is located at a distance of 117.6 light-years (36.1 parsecs).[1] The star is moving away from the Sun with a radial velocity of +21.6 km/s.[5]
The stellar classification of K2 III[3] indicates this is an evolved giant star of the K class. This means it has consumed the hydrogen at its core and has migrated away from the main sequence, with its outer envelope cooling and expanding in the process. Alpha Horologii has an estimated 1.41 times the mass of the Sun[2] and is radiating 38[7] times the Sun's luminosity from its photosphere at an effective temperature of 4,695 K.[2] Being 3.56 billion years old, it has swollen to around 10 times the diameter of the Sun,[2] having spent much of its life as a white main sequence star.[10]
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.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Gomes da Silva, J.; Santos, N. C.; Adibekyan, V.; Sousa, S. G.; Campante, T. L.; Figueira, P.; Bossini, D.; Delgado-Mena, E. et al. (2021-02-01). "Stellar chromospheric activity of 1674 FGK stars from the AMBRE-HARPS sample. I. A catalogue of homogeneous chromospheric activity". Astronomy and Astrophysics 646: A77. doi:10.1051/0004-6361/202039765. ISSN 0004-6361. Bibcode: 2021A&A...646A..77G. https://ui.adsabs.harvard.edu/abs/2021A&A...646A..77G. Alpha Horologii's database entry at VizieR.
- ↑ 3.0 3.1 Gray, R. O. et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Northern Sample I", The Astronomical Journal 132 (1): 161–170, doi:10.1086/504637, Bibcode: 2006AJ....132..161G.
- ↑ Cousins, A. W. J. (1973), "Revised zero points and UBV photometry of stars in the Harvard E and F regions", Memoirs of the Royal Astronomical Society 77: 223–236, Bibcode: 1973MmRAS..77..223C.
- ↑ 5.0 5.1 de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics 546: 14, doi:10.1051/0004-6361/201219219, A61, Bibcode: 2012A&A...546A..61D.
- ↑ Liu, Y. J.; Zhao, G.; Shi, J. R.; Pietrzyński, G.; Gieren, W. (2007). "The abundances of nearby red clump giants". Monthly Notices of the Royal Astronomical Society 382 (2): 553–66. doi:10.1111/j.1365-2966.2007.11852.x. Bibcode: 2007MNRAS.382..553L.
- ↑ 7.0 7.1 McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (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.
- ↑ "Alpha Horologii". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=Alpha+Horologii.
- ↑ 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.
- ↑ Kaler, Jim. "Alpha Horologii". http://stars.astro.illinois.edu/sow/alphahor.html. Retrieved 20 September 2019.
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