Astronomy:26 Ursae Majoris
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Ursa Major[1] |
| Right ascension | 09h 34m 49.43259s[2] |
| Declination | +52° 03′ 05.3165″[2] |
| Apparent magnitude (V) | 4.47[1] |
| Characteristics | |
| Evolutionary stage | main sequence[3] |
| Spectral type | A0 Vn[4] |
| U−B color index | +0.00[5] |
| B−V color index | +0.027±0.013[1] |
| Astrometry | |
| Radial velocity (Rv) | +22.2±1.1[6] km/s |
| Proper motion (μ) | RA: −65.74[2] mas/yr Dec.: −37.32[2] mas/yr |
| Parallax (π) | 12.44 ± 0.19[2] mas |
| Distance | 262 ± 4 ly (80 ± 1 pc) |
| Absolute magnitude (MV) | −0.06[1] |
| Details | |
| Mass | 2.16[7] M☉ |
| Radius | 2.2[8] R☉ |
| Luminosity | 99.2[1] L☉ |
| Surface gravity (log g) | 3.94[7] cgs |
| Temperature | 9,757±332[7] K |
| Rotational velocity (v sin i) | 165[4] km/s |
| Age | 147[7] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
26 Ursae Majoris is a single[10] star in the northern circumpolar constellation of Ursa Major, located 262 light years away from the Sun.[2] It is visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of 4.47.[1] The object is moving further from the Earth with a heliocentric radial velocity of +22 km/s.[6]
This is an A-type main-sequence star with a stellar classification of A0 Vn,[4] where the 'n' indicates "nebulous" lines in the spectrum due to rapid rotation. It has a high rate of spin with a projected rotational velocity of 165 km/s,[4] which is giving it an oblate shape with an equatorial bulge that is 8% larger than the polar radius.[11] The star is 147[7] million years old with just over double[7] the mass of the Sun and twice[8] the Sun's radius. It is radiating 99[1] times the Sun's luminosity from its photosphere at an effective temperature of 9,757 K.[7]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A XHIP record for this object at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 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.
- ↑ Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". Astronomy and Astrophysics 537: A120. doi:10.1051/0004-6361/201117691. Bibcode: 2012A&A...537A.120Z.
- ↑ 4.0 4.1 4.2 4.3 Abt, Helmut A.; Morrell, Nidia I. (1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars". Astrophysical Journal Supplement 99: 135. doi:10.1086/192182. Bibcode: 1995ApJS...99..135A.
- ↑ Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode: 1986EgUBV........0M.
- ↑ 6.0 6.1 Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters 32 (11): 759–771. doi:10.1134/S1063773706110065. Bibcode: 2006AstL...32..759G.
- ↑ 7.0 7.1 7.2 7.3 7.4 7.5 7.6 David, Trevor J.; Hillenbrand, Lynne A. (2015). "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets". The Astrophysical Journal 804 (2): 146. doi:10.1088/0004-637X/804/2/146. Bibcode: 2015ApJ...804..146D.
- ↑ 8.0 8.1 Pasinetti Fracassini, L. E. et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics 367: 521–524, doi:10.1051/0004-6361:20000451, Bibcode: 2001A&A...367..521P.
- ↑ "26 UMa". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=26+UMa.
- ↑ Eggleton, P. P.; Tokovinin, A. A. (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.
- ↑ van Belle, Gerard T. (March 2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review 20 (1): 51, doi:10.1007/s00159-012-0051-2, Bibcode: 2012A&ARv..20...51V
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