  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ursa Major[1] |
| 23 UMa A | |
| Right ascension | 09h 31m 31.70873s[2] |
| Declination | +63° 03′ 42.7013″[2] |
| Apparent magnitude (V) | +3.65[1] |
| 23 UMa B | |
| Right ascension | 09h 31m 28.36401s[3] |
| Declination | +63° 03′ 41.8990″[3] |
| Apparent magnitude (V) | +9.19[4] |
| Characteristics | |
| 23 UMa A | |
| Evolutionary stage | main sequence[5] |
| Spectral type | F0IV[6] |
| B−V color index | 0.360±0.015[1] |
| 23 UMa B | |
| Evolutionary stage | main sequence[4] |
| Spectral type | K5V[7] |
| Astrometry | |
| 23 UMa A | |
| Radial velocity (Rv) | −10.4±0.7[1] km/s |
| Proper motion (μ) | RA: +107.99[2] mas/yr Dec.: +27.15[2] mas/yr |
| Parallax (π) | 41.99±0.16 mas[2] |
| Distance | 77.7 ± 0.3 ly (23.82 ± 0.09 pc) |
| Absolute magnitude (MV) | +1.77[1] |
| 23 UMa B | |
| Radial velocity (Rv) | −2.55±0.13[3] km/s |
| Proper motion (μ) | RA: +108.861[3] mas/yr Dec.: +13.972[3] mas/yr |
| Parallax (π) | 42.2161±0.0166 mas[3] |
| Distance | 77.26 ± 0.03 ly (23.688 ± 0.009 pc) |
| Details | |
| 23 UMa A | |
| Mass | 1.44[8] M☉ |
| Radius | 2.84[8] R☉ |
| Luminosity | 15.1[8] L☉ |
| Surface gravity (log g) | 3.69[8] cgs |
| Temperature | 6,748[8] K |
| Metallicity [Fe/H] | 0.17[6] dex |
| Rotational velocity (v sin i) | 154[5] km/s |
| Age | 1.3[6] Gyr |
| 23 UMa B | |
| Mass | 0.69[8] M☉ |
| Radius | 0.68[8] R☉ |
| Luminosity | 0.16[8] L☉ |
| Surface gravity (log g) | 4.61[8] cgs |
| Temperature | 4,436[8] K |
| Metallicity [Fe/H] | 0.06[9] dex |
| Other designations | |
| h UMa, 23 UMa, BD+63°845, FK5 355, GJ 3534, HD 81937, HIP 46733, HR 3757, SAO 14908, CCDM J09315+6303A/B[10] | |
| Database references | |
| SIMBAD | data |
23 Ursae Majoris, or 23 UMa, is a binary star system in the constellation Ursa Major,[10] located is approximately 77.7 light years from the Sun.[2] 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.[1] It is moving closer to the Earth with a heliocentric radial velocity of −10 km/s.[1]
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[11] at an effective temperature of 6,651 K.[6] 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
[edit]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.[12] According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Al-Haud was 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 .[13]
References
[edit]- ^ a b c d e f g 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.
- ^ a b c d e f 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.
- ^ a b c d e f 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.
- ^ a b Hardegree-Ullman, Kevin K.; Apai, Dániel; Bergsten, Galen J.; Pascucci, Ilaria; López-Morales, Mercedes (2023). "Bioverse: A Comprehensive Assessment of the Capabilities of Extremely Large Telescopes to Probe Earth-like O2 Levels in Nearby Transiting Habitable-zone Exoplanets". The Astronomical Journal. 165 (6): 267. arXiv:2304.12490. Bibcode:2023AJ....165..267H. doi:10.3847/1538-3881/acd1ec.
- ^ a b Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". Astronomy and Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691.
- ^ a b c d 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.
- ^ Salama, Maïssa; Ziegler, Carl; Baranec, Christoph; Liu, Michael C.; Law, Nicholas M.; Riddle, Reed; Henry, Todd J.; Winters, Jennifer G.; Jao, Wei-Chun; Ou, James; Hermosillo Ruiz, Arcelia (2022). "An Adaptive Optics Census of Companions to Northern Stars within 25 pc with Robo-AO". The Astronomical Journal. 163 (5): 200. arXiv:2203.11250. Bibcode:2022AJ....163..200S. doi:10.3847/1538-3881/ac53fc.
- ^ a b c d e f g h i j Stassun, Keivan G.; et al. (2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv:1905.10694. Bibcode:2019AJ....158..138S. doi:10.3847/1538-3881/ab3467.
- ^ Huson, Dylan; Cowan, Indiana; Sizemore, Logan; Kounkel, Marina; Hutchinson, Brian (2025). "Gaia Net: Toward Robust Spectroscopic Parameters of Stars of all Evolutionary Stages". The Astrophysical Journal. 984 (1): 58. arXiv:2503.02958. Bibcode:2025ApJ...984...58H. doi:10.3847/1538-4357/adc2fa.
- ^ a b "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.
