| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Ursa Minor |
| Right ascension | 15 17 05.89154 |
| Declination | +71° 49′ 26.0375″ |
| Apparent magnitude (V) | 5.15 |
| Characteristics | |
| Spectral type | K4 III |
| Apparent magnitude (B) | 6.664 |
| Apparent magnitude (J) | 2.657 |
| Apparent magnitude (H) | 1.931±0.192 |
| Apparent magnitude (K) | 1.701±0.198 |
| B−V color index | 1.514±0.004 |
| Astrometry | |
| Radial velocity (Rv) | −17.52±0.15 km/s |
| Proper motion (μ) | RA: 3.430 mas/yr Dec.: 10.113 mas/yr |
| Parallax (π) | 7.9539 ± 0.1249 mas |
| Distance | 410 ± 6 ly (126 ± 2 pc) |
| Absolute magnitude (MV) | –0.37 |
| Details | |
| Mass | 2.04±0.20 M☉ |
| Radius | 28.20+0.71 −0.73 R☉ |
| Luminosity | 258.8±17.7 L☉ |
| Surface gravity (log g) | 1.60 cgs |
| Temperature | 4,358±59 K |
| Metallicity | 0.04 ± 0.04 |
| Age | 1.21±0.33 Gyr |
| Other designations | |
| 11 UMi, V1032 UMi, BD+72°678, FK5 1140, HD 136726, HIP 74793, HR 5714, SAO 8207, PPM 8870, GCRV 8864 | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
11 Ursae Minoris is a single star located approximately 410 light years away in the northern circumpolar constellation of Ursa Minor. The star is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 5.15. It is moving closer to the Earth with a heliocentric radial velocity of −17.5 km/s.
This is an aging K-type giant star with a stellar classification of K4 III. It is 1.2 billion years old with twice the mass of the Sun. As a consequence of exhausting the hydrogen at its core, the star has expanded to 28 times the Sun's radius. It is radiating 258 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,358 K.
11 Ursae Minoris is sometimes named Pherkard or Pherkad Minor, the later name to distinguish it from Pherkad (Major) which is γ Ursae Minoris. It has also been designated as γ Ursae Minoris, in which case the brighter Pherkad is called γ Ursae Minoris, but these names are rarely used. 11 Ursae Minoris is the Flamsteed designation.
11 Ursae Minoris has a detected planet discovered in August 2009.
Planetary system
11 Ursae Minoris b was discovered during a radial velocity survey of 62 K type Red giant stars using the 2m Alfred Jensch telescope of the Thuringian State Observatory in Germany.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥10.50 ± 2.47 MJ | 1.54 ± 0.07 | 516.22 ± 3.25 | 0.08 ± 0.03 | — | — |
See also
References
- ^ 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.
- ^ 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.
- ^ Baines, Ellyn K.; et al. (2018). "Fundamental Parameters of 87 Stars from the Navy Precision Optical Interferometer". The Astronomical Journal. 155 (1). 30. arXiv:1712.08109. Bibcode:2018AJ....155...30B. doi:10.3847/1538-3881/aa9d8b. S2CID 119427037.
- ^ Döllinger, P.; et al. (2009). "Planetary companions around the K giant stars 11 Ursae Minoris and HD 32518". Astronomy and Astrophysics. 505 (3): 1311–1317. arXiv:0908.1753. Bibcode:2009A&A...505.1311D. doi:10.1051/0004-6361/200911702. S2CID 9686080.
- "11 UMi". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 8 September 2012.
- 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.
- Kostjuk, N. D. (2004). "VizieR Online Data Catalog: HD-DM-GC-HR-HIP-Bayer-Flamsteed Cross Index (Kostjuk, 2002)". VizieR On-line Data Catalog: IV/27A. Originally Published in: Institute of Astronomy of Russian Academy of Sciences (2002). 4027. Bibcode:2004yCat.4027....0K.
External links
- Jean Schneider (2011). "Notes for star 11 UMi". Extrasolar Planets Encyclopaedia. Archived from the original on August 19, 2009. Retrieved 30 September 2011.
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