23 Ursae Majoris
23 Ursae Majoris, or 23 UMa, is a binary star system in the constellation Ursa Major,[4] located is approximately 77.7 light years from the Sun.[1] It has the Bayer designation h Ursae Majoris; 23 Ursae Majoris is the Flamsteed designation. The system is visible to the naked eye as a yellow-white hued star with an apparent visual magnitude of +3.65.[2] It is moving closer to the Earth with a heliocentric radial velocity of −10 km/s.[2]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ursa Major |
| Right ascension | 09h 31m 31.70873s[1] |
| Declination | +63° 03′ 42.7013″[1] |
| Apparent magnitude (V) | +3.65[2] / +9.0 |
| Characteristics | |
| Spectral type | F0IV[3] |
| B−V color index | 0.360±0.015[2] |
| Astrometry | |
| Radial velocity (Rv) | −10.4±0.7[2] km/s |
| Proper motion (μ) | RA: +107.99[1] mas/yr Dec.: + 27.15[1] mas/yr |
| Parallax (π) | 41.99 ± 0.16[1] mas |
| Distance | 77.7 ± 0.3 ly (23.82 ± 0.09 pc) |
| Details | |
| 23 UMa A | |
| Mass | 1.862[3] M☉ |
| Radius | 2.90±0.03[3] R☉ |
| Luminosity | 14.8±0.1[3] L☉ |
| Temperature | 6,651±27[3] K |
| Metallicity [Fe/H] | 0.17[3] dex |
| Age | 1.3[3] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
The primary component is a yellow-white F-type subgiant with an apparent magnitude of +3.65. It has 1.9 times the Sun's mass, 2.9 times the Sun's radius and is emitting 15 times the luminosity of the Sun[5] at an effective temperature of 6,651 K.[3] Orbiting at an angular separation of 22.7 arcseconds is the 9th magnitude secondary companion. There is a magnitude +10.5 optical companion at an angular separation of 99.6 arcseconds.
Nomenclature
With τ, υ, φ, θ, e and f, it composed the Arabic asterism Sarīr Banāt al-Na'sh, the Throne of the daughters of Na'sh, and Al-Haud, the Pond.[6] According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Al-Haud were the title for seven stars : f as Alhaud I, τ as Alhaud II, e as Alhaud III, this star (h) as Alhaud IV, θ as Alhaud V, υ as Alhaud VI and φ as Alhaud VII .[7]
References
- Van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
- 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, S2CID 119257644.
- Boyajian, Tabetha S.; et al. (July 2013), "Stellar Diameters and Temperatures. III. Main-sequence A, F, G, and K Stars: Additional High-precision Measurements and Empirical Relations", The Astrophysical Journal, 771 (1): 31, arXiv:1306.2974, Bibcode:2013ApJ...771...40B, doi:10.1088/0004-637X/771/1/40, S2CID 14911430, 40. See Table 3.
- "h UMa". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-03-19.
- Boyajian, Tabetha S.; et al. (February 2012), "Stellar Diameters and Temperatures. I. Main-sequence A, F, and G Stars", The Astrophysical Journal, 746 (1): 101, arXiv:1112.3316, Bibcode:2012ApJ...746..101B, doi:10.1088/0004-637X/746/1/101, S2CID 18993744. See Table 10.
- Allen, Richard Hinckley (1899), Star-Names and Their Meanings, New York: G. E. Stechert, p. 442.
- Rhoads, Jack W. (November 15, 1971), Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars (PDF), Jet Propulsion Laboratory, California Institute of Technology.