Observation data Epoch J2000.0 Equinox J2000.0 ( ICRS) | |
---|---|
Constellation | Ursa Major |
Right ascension | 09h 08m 23.49946s [1] |
Declination | +66° 52′ 23.6492″ [1] |
Apparent magnitude (V) | 5.14 [2] |
Characteristics | |
Spectral type | K5 III [3] |
U−B color index | +1.80 [2] |
B−V color index | +1.52 [2] |
Astrometry | |
Radial velocity (Rv) | 14.60±0.19 [4] km/s |
Proper motion (μ) |
RA: −22.68
[1]
mas/
yr Dec.: −40.11 [1] mas/ yr |
Parallax (π) | 6.26 ± 0.30 mas [1] |
Distance | 520 ± 20
ly (160 ± 8 pc) |
Absolute magnitude (MV) | −0.93 [3] |
Details | |
Radius | 46 [5] R☉ |
Luminosity | 560±20 [3] L☉ |
Surface gravity (log g) | 1.66 [6] cgs |
Temperature | 3,940 [6] K |
Metallicity [Fe/H] | −0.23 [6] dex |
Other designations | |
Database references | |
SIMBAD | data |
Sigma1 Ursae Majoris (σ1 UMa) is the Bayer designation for a solitary [8] star in the northern circumpolar constellation of Ursa Major. With an apparent visual magnitude of 5.14 [2] it is faintly visible to the naked eye on dark nights. Based upon an annual parallax shift of 6.26 mas, [1] it is located roughly 520 light years from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction factor of 0.06 [3] due to interstellar dust.
This is an evolved K-type giant star with a stellar classification of K5 III. [3] It is a suspected variable with an amplitude of 0.03 magnitude. [3] The measured angular diameter of the star after correcting for limb darkening is 2.67±0.04 mas, [9] which, at the estimated distance of this star, yields a physical size of about 46 times the radius of the Sun. [5] The star is radiating around 560 [3] times the solar luminosity from its outer atmosphere at an effective temperature of 3,940 K. [6]
With π1, π2, σ2, ρ, A and d, it composed the Arabic asterism Al Ṭhibā᾽, the Gazelle. [10] According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Al Ṭhibā were the title for seven stars : A as Althiba I, this star (π1) as Althiba II, π2 as Althiba III, ρ as Althiba IV, this star (σ1) as Althiba V, σ2 as Althiba VI, and d as Althiba VII. [11]
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cite web}}
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Observation data Epoch J2000.0 Equinox J2000.0 ( ICRS) | |
---|---|
Constellation | Ursa Major |
Right ascension | 09h 08m 23.49946s [1] |
Declination | +66° 52′ 23.6492″ [1] |
Apparent magnitude (V) | 5.14 [2] |
Characteristics | |
Spectral type | K5 III [3] |
U−B color index | +1.80 [2] |
B−V color index | +1.52 [2] |
Astrometry | |
Radial velocity (Rv) | 14.60±0.19 [4] km/s |
Proper motion (μ) |
RA: −22.68
[1]
mas/
yr Dec.: −40.11 [1] mas/ yr |
Parallax (π) | 6.26 ± 0.30 mas [1] |
Distance | 520 ± 20
ly (160 ± 8 pc) |
Absolute magnitude (MV) | −0.93 [3] |
Details | |
Radius | 46 [5] R☉ |
Luminosity | 560±20 [3] L☉ |
Surface gravity (log g) | 1.66 [6] cgs |
Temperature | 3,940 [6] K |
Metallicity [Fe/H] | −0.23 [6] dex |
Other designations | |
Database references | |
SIMBAD | data |
Sigma1 Ursae Majoris (σ1 UMa) is the Bayer designation for a solitary [8] star in the northern circumpolar constellation of Ursa Major. With an apparent visual magnitude of 5.14 [2] it is faintly visible to the naked eye on dark nights. Based upon an annual parallax shift of 6.26 mas, [1] it is located roughly 520 light years from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction factor of 0.06 [3] due to interstellar dust.
This is an evolved K-type giant star with a stellar classification of K5 III. [3] It is a suspected variable with an amplitude of 0.03 magnitude. [3] The measured angular diameter of the star after correcting for limb darkening is 2.67±0.04 mas, [9] which, at the estimated distance of this star, yields a physical size of about 46 times the radius of the Sun. [5] The star is radiating around 560 [3] times the solar luminosity from its outer atmosphere at an effective temperature of 3,940 K. [6]
With π1, π2, σ2, ρ, A and d, it composed the Arabic asterism Al Ṭhibā᾽, the Gazelle. [10] According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Al Ṭhibā were the title for seven stars : A as Althiba I, this star (π1) as Althiba II, π2 as Althiba III, ρ as Althiba IV, this star (σ1) as Althiba V, σ2 as Althiba VI, and d as Althiba VII. [11]
{{
cite web}}
: CS1 maint: postscript (
link)