2 Ursae Minoris

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2 Ursae Minoris
Observation data
Epoch J2000       Equinox J2000
Constellation Cepheus
Right ascension 01h 08m 44.88005s [1]
Declination 86° 15 25.5240 [1]
Apparent magnitude  (V)4.244 [2]
Characteristics
Spectral type K2 II-III [3]
B−V color index 1.213±0.012 [4]
Astrometry
Radial velocity (Rv)+8.36±0.19 [5]  km/s
Proper motion (μ)RA: 80.65±0.16 [1]   mas/yr
Dec.: −11.54±0.17 [1]   mas/yr
Parallax (π)11.64 ± 0.15  mas [1]
Distance 280 ± 4  ly
(86 ± 1  pc)
Absolute magnitude  (MV)−0.43 [4]
Details
Mass 2.27±0.41 [6]   M
Radius 24.00+1.15
−0.85
[5]   R
Luminosity 215.097±6.132 [5]   L
Surface gravity (log g)2.48±0.17 [2]   cgs
Temperature 4,512.5+62.2
−105.0
[5]   K
Metallicity [Fe/H]0.068±0.010 [2]   dex
Rotational velocity (v sin i)1.0 [7]  km/s
Other designations
2 UMi, BD+85°19, FK5  906, HD  5848, HIP  5372, HR  285, SAO  181 [8]
Database references
SIMBAD data

2 Ursae Minoris (2 UMi) is a single [9] star a few degrees away from the northern celestial pole. Despite its Flamsteed designation, the star is actually located in the constellation Cepheus. This changed occurred when the constellation boundaries were formally set in 1930 by Eugene Delporte. Therefore, the star is usually referred only by its catalog numbers such as HR 285 or HD 5848. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.244. [2] This object is located 280  light years away and is moving further from the Earth with a heliocentric radial velocity of +8 km/s. [5] It is a candidate member of the Hyades Supercluster. [2]

This is an aging K-type star with a stellar classification of K2 II-III, [3] showing a luminosity class with blended traits of a giant and a bright giant. It has 2.3 [6] times the mass of the Sun and has expanded to 24 [5] times the Sun's radius. The star is radiating around 215 [5] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,513 K. [5]

Related Research Articles

Psi Ursae Majoris is a star in the northern circumpolar constellation of Ursa Major. It has an apparent visual magnitude of +3.01, making it a third magnitude star and one of the brighter members of the constellation. Parallax measurements place it at a distance of 144.5 light-years from Earth. This is sufficiently close that the magnitude of the star is only reduced by 0.05 due to extinction. In Chinese astronomy, Psi Ursae Majoris is called Tien Tsan or Ta Tsun, "Extremely Honorable". The name was possibly derived from the word 太尊, Pinyin: Tàizūn, meaning Royals, because this star stands alone as the only member of the Royals asterism within the Purple Forbidden enclosure.

<span class="mw-page-title-main">Eta Ursae Minoris</span> Star of the Ursa Minor constellation

Eta Ursae Minoris is a yellow-white hued star in the northern circumpolar constellation of Ursa Minor.

<span class="mw-page-title-main">Theta Ursae Minoris</span> Suspected binary star in the constellation Ursa Minor

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. The system is moving closer to the Sun with a radial velocity of −25 km/s.

Pi1 Ursae Minoris is a common proper motion binary star system in the northern circumpolar constellation of Ursa Minor. The pair have apparent visual magnitudes of +6.58 and +7.31, with a combined magnitude of 6.1. They are located about 71 light years from the Sun. The two have an angular separation of 31.4 arc seconds, which corresponds to a physical separation of about 680 AU, and orbit each other with a period of about 13,100 years.

<span class="mw-page-title-main">82 Cancri</span> Star in the constellation Cancer

82 Cancri is a solitary, orange-hued star in the zodiac constellation of Cancer. It has the Bayer designation Pi2 Cancri, which is Latinized from π2 Cancri; 82 Cancri is the star's Flamsteed designation. The star lies just a degree to the south of the ecliptic. With an apparent visual magnitude of +5.33, it is dimly visible to the naked eye on a dark night. This star is located at a distance of approximately 540 light years from the Sun based on parallax. At that range, the visual magnitude is diminished by an extinction of 0.10 magnitudes due to interstellar dust. It is drifting further away with a radial velocity of +27 km/s.

<span class="mw-page-title-main">20 Canum Venaticorum</span> Star in the constellation Canes Venatici

20 Canum Venaticorum is a single variable star in the northern constellation of Canes Venatici, located 238 light years from the Sun. This object has the variable star designation AO Canum Venaticorum; 20 Canum Venaticorum is the Flamsteed designation. It is visible to the naked eye as a faint, white-hued star with a baseline apparent visual magnitude of +4.72. The star is moving further from the Earth with a heliocentric radial velocity of +9 km/s. Eggen (1971) listed this star as a member of the Hyades Stream.

C3 Centauri is a suspected astrometric binary star system in the southern constellation of Centaurus. It has an orange hue and is dimly visible to the naked eye with an apparent visual magnitude of +5.46. The distance to this object is approximately 342 light years based on parallax. It is a member of the Hyades Stream of co-moving stars.

HD 32518 is a solitary star in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 6.42, placing it near the max naked eye visibility. Located about 400 light years away, it is receding with a heliocentric radial velocity of −7.02 km/s.

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.

Gamma Comae Berenices, Latinized from γ Comae Berenices, is a single, orange-hued star in the northern constellation of Coma Berenices. It is faintly visible to the naked eye, having an apparent visual magnitude of 4.36. Based upon an annual parallax shift of 19.50 mas as seen from Earth, its distance can be estimated as around 167 light years from the Sun. The star is moving away from the Sun with a radial velocity of +3 km/s.

21 Camelopardalis is a star in the northern circumpolar constellation of Camelopardalis, located around 650 light years away from the Sun. It is a challenge to view with the naked eye even under excellent viewing conditions, having an apparent visual magnitude of 6.9. This is one of the fainter stars with a Flamsteed designation, one of only 220 below the magnitude cutoff for the Bright Star Catalogue. It is moving closer to the Earth with a heliocentric radial velocity of −15.5 km/s.

<span class="mw-page-title-main">Eta Sagittae</span> Star in the constellation Sagitta

Eta Sagittae (η Sagittae) is solitary star in the northern constellation of Sagitta. It is faintly visible to the naked eye, having an apparent visual magnitude of +5.09. Based upon an annual parallax shift of 20.34 mas, it is approximately 160 light years distant from the Sun. There is a 61.1% chance that it is a member of the Hyades-Pleiades stream of stars that share a common motion through space.

<span class="mw-page-title-main">18 Draconis</span> Star in the constellation Draco

18 Draconis is a likely binary star system in the northern circumpolar constellation of Draco. With an apparent visual magnitude of 4.84, it is just bright enough to be faintly visible to the naked eye. The distance to this system, as estimated from an annual parallax shift of 4.5 mas, is roughly 720 light years. It is moving closer to the Sun with a heliocentric radial velocity of −1.4 km/s, and is a probable member of the Sirius stream of co-moving stars.

HD 217382 is a suspected binary star system in the northern circumpolar constellation of Cepheus. It is faintly visible to the naked eye with an apparent visual magnitude of 4.70. The distance to HD 217382 is around 373 light years, as determined from an annual parallax shift of 8.74 mas. The system is moving further away with a heliocentric radial velocity of +2.6 km/s. It is a candidate member of the Hyades supercluster and has a peculiar velocity of 9.2 km/s.

<span class="mw-page-title-main">RR Ursae Minoris</span> Star in the constellation Ursa Minor

RR Ursae Minoris, abbreviated RR UMi, is a binary star system in the northern circumpolar constellation of Ursa Minor. It can be viewed with the naked eye, typically having an apparent visual magnitude of around 4.710. Based upon an annual parallax shift of 10.0 mas as seen from Earth's orbit, it is located 330 light years away. The system is moving further from the Sun with a heliocentric radial velocity of +6 km/s.

4 Ursae Minoris is a binary star system in the northern circumpolar constellation Ursa Minor. It is faintly visible to the naked eye with an apparent visual magnitude of 4.80. Based upon an annual parallax shift of 7.14±0.42 mas as seen from Earth's orbit, it is located roughly 460 light years from the Sun. It is moving further away with a heliocentric radial velocity of +5.9 km/s.

ι2 Muscae, Latinised as Iota2 Muscae, is a blue-white-hued star in the southern constellation Musca, near the constellation's southern border with Chamaeleon. It has an apparent visual magnitude of 6.62, which is just below the normal limit of stellar brightness visible to the naked eye. Based upon parallax measurements, it is located around 492 light-years from the Sun. It is a member of the Hyades Stream, but is not part of the Hyades or Praesepe open clusters.

8 Persei is a single star in the northern constellation of Perseus, located 416 light years away from the Sun. It is visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of 5.757. There is an estimated 52% chance that the star may be a member of the Hyades–Pleiades stream of co-moving stars.

HD 75171, also known as HR 3495, is a solitary, white hued star located in the southern constellation of Volans. It has an apparent magnitude of 6.02, making it faintly visible to the naked eye under ideal conditions. The object is relatively close at a distance of 191 light years but is receding with a heliocentric radial velocity of 10.7 km/s. Eggen (1995) lists it as a probable member of the Hyades Supercluster.

<span class="mw-page-title-main">23 Leonis Minoris</span> Star in the constellation of Leo Minor

23 Leonis Minoris is a solitary, bluish-white hued star located in the northern constellation Leo Minor. It is positioned 7° south and 11" west from β Leonis Minoris. It is rarely called 7 H. Leonis Minoris, which is its Hevelius designation.

References

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