HD 111456 is a yellow-white hued star in the northern circumpolar constellation of Ursa Major. It is dimly visible to the naked eye, having an apparent visual magnitude of 5.85.[2] Based upon an annual parallax shift of 38.2 mas as seen from Earth, it is located about 85 light years from the Sun. The star is moving closer to the Sun with a radial velocity of −18 km/s.[4] HD 111456 is a nucleus cluster member of the Ursa Major Moving Group, a set of stars that are moving through space with a similar heading and velocity. Six other stars in the nucleus of the group are prominent members of the Big Dipper asterism.[3]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Ursa Major |
| Right ascension | 12h 48m 39.44700s[1] |
| Declination | 60° 19′ 11.0379″[1] |
| Apparent magnitude (V) | 5.85[2] |
| Characteristics | |
| Spectral type | F7 V[3] |
| U−B color index | −0.04[2] |
| B−V color index | +0.46[2] |
| Astrometry | |
| Radial velocity (Rv) | −18.0±0.9[4] km/s |
| Proper motion (μ) | RA: +120.949[1] mas/yr Dec.: +35.712[1] mas/yr |
| Parallax (π) | 38.1905 ± 0.2904 mas[1] |
| Distance | 85.4 ± 0.6 ly (26.2 ± 0.2 pc) |
| Absolute magnitude (MV) | +4.2±0.2[5] |
| Details | |
| Radius | 1.22[5] R☉ |
| Luminosity | 6.45[6] L☉ |
| Surface gravity (log g) | 4.5[5] cgs |
| Temperature | 6,400[5] K |
| Rotational velocity (v sin i) | 41.5±1.1[5] km/s |
| Age | 300−400[5] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
The stellar classification for this star is F7 V,[3] indicating that it is an ordinary F-type main-sequence star. It is young, around 300−400 million years of age, and is spinning with a relatively high projected rotational velocity of 41.5 km/s.[5] This is one of the most active F-type stars known, and it is a strong emitter of X-rays[5] and an extreme UV source. It is an astrometric binary with a period of four years and a mass ratio of 0.5. Hence, the companion may be a young white dwarf star.[8]
References
edit- ^ a b c d e Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b c d Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J.
- ^ a b c Levato, H.; Abt, H. A. (August 1978), "Spectral types in the Ursa Major stream", Publications of the Astronomical Society of the Pacific, 90: 429−433, Bibcode:1978PASP...90..429L, doi:10.1086/130352.
- ^ a b 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, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
- ^ a b c d e f g h Freire Ferrero, R.; et al. (January 2004), "Magnetic activity in HD 111456, a young F5-6 main-sequence star", Astronomy and Astrophysics, 413 (2): 657−667, Bibcode:2004A&A...413..657F, doi:10.1051/0004-6361:20031565.
- ^ 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.
- ^ "HR 4867". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-10-25.
{{cite web}}: CS1 maint: postscript (link) - ^ Goldin, A.; Makarov, V. V. (September 2006), "Unconstrained Astrometric Orbits for Hipparcos Stars with Stochastic Solutions", The Astrophysical Journal Supplement Series, 166 (1): 341−350, arXiv:astro-ph/0606293, Bibcode:2006ApJS..166..341G, doi:10.1086/505939, S2CID 15673734.