| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Ursa Minor |
| Right ascension | 15h 17m 05.89154s [1] |
| Declination | +71° 49′ 26.0375″ [1] |
| Apparent magnitude (V) | 5.15 [2] |
| Characteristics | |
| Spectral type | K4 III [3] |
| Apparent magnitude (B) | 6.664 [2] |
| Apparent magnitude (J) | 2.657 [2] |
| Apparent magnitude (H) | 1.931±0.192 [2] |
| Apparent magnitude (K) | 1.701±0.198 [2] |
| B−V color index | 1.514±0.004 [2] |
| Astrometry | |
| Radial velocity (Rv) | −17.52±0.15 [1] km/s |
| Proper motion (μ) |
RA: 3.430
[1]
mas/
yr Dec.: 10.113 [1] mas/ yr |
| Parallax (π) | 7.9539 ± 0.1249 mas [1] |
| Distance | 410 ± 6
ly (126 ± 2 pc) |
| Absolute magnitude (MV) | –0.37 [4] |
| Details [3] | |
| 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 [4] cgs |
| Temperature | 4,358±59 K |
| Metallicity | 0.04 ± 0.04 [4] |
| Age | 1.21±0.33 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
|
Extrasolar Planets Encyclopaedia | data |
11 Ursae Minoris is a single [6] star located approximately 410 light years away [1] 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. [2] It is moving closer to the Earth with a heliocentric radial velocity of −17.5 km/s. [1]
This is an aging K-type giant star with a stellar classification of K4 III. [3] It is 1.2 billion years old with twice the mass of the Sun. [3] As a consequence of exhausting the hydrogen at its core, the star has expanded to 28 times the Sun's radius. [3] It is radiating 258 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,358 K. [3]
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 γ1 Ursae minoris, in which case the brighter Pherkad is called γ2 Ursae minoris, but these names are rarely used. [7] 11 Ursae Minoris is the Flamsteed designation.
11 Ursae minoris has a detected planet discovered in August 2009. [4]
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. [4]
| 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
- ^ a b c d e f g h 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 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. S2CID 119257644.
- ^ a b c d e f 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.
- ^ a b c d e f 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. Retrieved 30 September 2011.
