Astronomy:11 Ursae Minoris
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| 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[1] mas |
| 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
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 Baines, Ellyn K. et al. (2018). "Fundamental Parameters of 87 Stars from the Navy Precision Optical Interferometer". The Astronomical Journal 155 (1): 30. doi:10.3847/1538-3881/aa9d8b. Bibcode: 2018AJ....155...30B.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 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. doi:10.1051/0004-6361/200911702. Bibcode: 2009A&A...505.1311D. http://www.aanda.org/articles/aa/full_html/2009/39/aa11702-09/aa11702-09.html.
- ↑ "11 UMi". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=11+UMi.
- ↑ 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ 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. http://exoplanet.eu/star.php?st=11+UMi.
Coordinates: 
15h 17m 05.8886s, +71° 49′ 26.044″
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