Theta Ursae Minoris
Template:Location mark Location of θ Ursae Minoris (circled) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ursa Minor |
| Right ascension | Template:RA[1] |
| Declination | Template:DEC[1] |
| Apparent magnitude (V) | 4.982[2] |
| Characteristics | |
| Spectral type | K5-III CN0.5[3] |
| B−V Template:Engvar | +1.553[2] |
| Variable type | suspected[4] |
| Astrometry | |
| Radial velocity (Rv) | Template:Val[5] km/s |
| Proper motion (μ) | RA: Template:Val[1] mas/yr Dec.: Template:Val[1] mas/yr |
| Parallax (π) | 3.81±0.37 mas[1] |
| Distance | Template:Rnd ± Template:Rnd ly (Template:Rnd ± Template:Rnd pc) |
| Absolute magnitude (MV) | −2.04[6] |
| Details | |
| Radius | 96[7] Template:Solar radius |
| Luminosity | 1,618[8] Template:Solar luminosity |
| Surface gravity (log g) | Template:Val[9] cgs |
| Temperature | Template:Val[9] K |
| Metallicity [Fe/H] | Template:Val[9] dex |
| Metallicity [Fe/H] | {{{metal_fe2}}} dex |
| Other designations | |
| Template:Odlist[10] | |
| Database references | |
| SIMBAD | data |
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Theta Ursae Minoris, Latinized from θ Ursae Minoris, is a suspected binary star system that is visible to the naked eye in the northern circumpolar constellation of Ursa Minor. It is roughly 860 light years from Earth with an apparent visual magnitude of 5.0.[2] The system is moving closer to the Sun with a radial velocity of −25 km/s.[5]
This is a probable spectroscopic binary, but the companion has not been detected directly.[11] The spectrum matches a stellar classification of K5-III CN0.5,[3] which would normally indicate an evolved, orange-hued giant star of type K that has a mild overabundance of cyanogen in the outer atmosphere. The estimated diameter is around 96 times that of the Sun,[7] and it is radiating approximately 1,618[8] times the Sun's luminosity from an expanded photosphere at an effective temperature of Template:Val.[9]
Photometry from the Hipparcos satellite mission shows that θ Ursae Minoris varies in brightness by a few hundredths of a magnitude. It is listed as NSV 20342 in the New Catalogue of Suspected Variable Stars.[12]
References
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<ref>tag; no text was provided for refs namedSchiavon2007 - ↑ a b Script error: No such module "citation/CS1". theta UMi' database entry at VizieR.
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