Tau Coronae Borealis
  | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Corona Borealis[1] |
| Right ascension | 16h 08m 58.309s[2] |
| Declination | +36° 29′ 27.134″[2] |
| Apparent magnitude (V) | 4.76[3] (4.89 + 13.2)[4] |
| Characteristics | |
| Evolutionary stage | red clump[5] |
| Spectral type | K1 III-IV[6] |
| U−B color index | +0.86[3] |
| B−V color index | +1.01[3] |
| Astrometry | |
| Radial velocity (Rv) | −21.02±0.33[7] km/s |
| Proper motion (μ) | RA: −59.431 mas/yr[2] Dec.: +332.280 mas/yr[2] |
| Parallax (π) | 29.0217±0.1275 mas[2] |
| Distance | 112.4 ± 0.5 ly (34.5 ± 0.2 pc) |
| Absolute magnitude (MV) | +2.03[1] |
| Details | |
| Mass | 1.45[8] M☉ |
| Radius | 6[7] R☉ |
| Luminosity | 16.2[7] L☉ |
| Surface gravity (log g) | 3.1[7] cgs |
| Temperature | 4,742[7] K |
| Metallicity [Fe/H] | −0.20[7] dex |
| Rotational velocity (v sin i) | 1.7[7] km/s |
| Age | 3.4 Gyr |
| Other designations | |
| τ CrB, 16 CrB, BD+36°2699, HD 145328, HIP 79119, HR 6018, SAO 65108[9] | |
| Database references | |
| SIMBAD | data |
Tau Coronae Borealis is a possible astrometric and spectroscopic binary star system in the northern constellation of Corona Borealis. Its name is a Bayer designation that is Latinized from τ Coronae Borealis, and abbreviated τ CrB or τ CrB. This system is visible to the naked eye with an apparent visual magnitude of 4.76.[3] Based upon an annual parallax shift of 29.02 mas as seen from Earth,[2] it is located about 112.4 light-years (34.5 pc) from the Sun. At that distance, the visual magnitude of the system is diminished by an extinction factor of 0.04 due to interstellar dust.[10]
Tau CrB has a visible companion of visual magnitude 13.2 and they have been treated as a common proper motion pair.[11] As of 2014, the pair had an angular separation of 2.20 arc seconds along a position angle of 186°.[11] It has also been described as a spectroscopic binary, but this has not been confirmed.[12] Due to an abnormal space motion, it has also been described as an astrometric binary although there is no apparent orbit.[4]
The primary component is a magnitude 4.89[4] K-type star with a stellar classification of K1 III-IV, having a spectrum that shows mixed traits of an evolved subgiant and giant star. It is catalogued as a red clump giant, which would indicate it is generating energy through helium fusion at its core.[5] The star has expanded to six times the Sun's radius and is radiating 16 times the solar luminosity from its photosphere at an effective temperature of 4,742 K.[7]
References
- 1 2 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015 XHIP record for this object at VizieR.
- 1 2 3 4 5 6 Vallenari, A.; et al. (Gaia collaboration) (2023), "Gaia Data Release 3. Summary of the content and survey properties", Astronomy and Astrophysics, 674: A1, arXiv:2208.00211, Bibcode:2023A&A...674A...1G, doi:10.1051/0004-6361/202243940, S2CID 244398875 Gaia DR3 record for this source at VizieR.
- 1 2 3 4 Nicolet, B. (1978), "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System", Astronomy and Astrophysics Supplement Series, 34: 1–49, Bibcode:1978A&AS...34....1N.
- 1 2 3 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, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- 1 2 Alves, David R. (August 2000), "K-Band Calibration of the Red Clump Luminosity", The Astrophysical Journal, 539 (2): 732–741, arXiv:astro-ph/0003329, Bibcode:2000ApJ...539..732A, doi:10.1086/309278, S2CID 16673121.
- ↑ Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins Catalog of Revised MK Types for the Cooler Stars", The Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.
- 1 2 3 4 5 6 7 8 Massarotti, Alessandro; et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209.
- ↑ Feuillet, Diane K.; et al. (2016), "Determining Ages of APOGEE Giants with Known Distances", The Astrophysical Journal, 817 (1): 40, arXiv:1511.04088, Bibcode:2016ApJ...817...40F, doi:10.3847/0004-637X/817/1/40.
- ↑ "tau CrB", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2017-04-30.
- ↑ Famaey, B.; et al. (January 2005), "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters", Astronomy and Astrophysics, 430 (1): 165–186, arXiv:astro-ph/0409579, Bibcode:2005A&A...430..165F, doi:10.1051/0004-6361:20041272, S2CID 17804304.
- 1 2 Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920.
- ↑ Hoffleit, D.; Warren, W. H. (1995), "Bright Star Catalogue", VizieR On-line Data Catalog: V/50. Originally Published in: 1964BS....C......0H, 5050 (5th Revised ed.), Bibcode:1995yCat.5050....0H.
Works related to Tau Coronae Borealis at Wikisource
