The red dot shows the location of Groombridge 1830 in Ursa Major. | |
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Ursa Major |
Right ascension | 11h 52m 58.76734s [1] |
Declination | +37° 43′ 07.2541″ [1] |
Apparent magnitude (V) | 6.44 [2] |
Characteristics | |
Spectral type | G8VIp [3] |
U−B color index | +0.16 [2] |
B−V color index | +0.75 [2] |
Variable type | Suspected [4] |
Astrometry | |
Radial velocity (Rv) | −98.05±0.12 [1] km/s |
Proper motion (μ) | RA: +4002.7 mas/yr [1] Dec.: −5817.8 mas/yr [1] |
Parallax (π) | 109.0296 ± 0.0197 mas [1] |
Distance | 29.914 ± 0.005 ly (9.172 ± 0.002 pc) |
Absolute magnitude (MV) | 6.64 [5] |
Details [6] | |
Mass | 0.63±0.02 M☉ |
Radius | 0.586±0.004 R☉ |
Luminosity | 0.221±0.005 L☉ |
Surface gravity (log g) | 4.702±0.015 cgs |
Temperature | 5,174±32 K |
Metallicity [Fe/H] | −1.26±0.07 dex |
Age | 4.7–5.3 [7] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
Groombridge 1830 (also known as 1830 Groombridge or Argelander's Star) [8] is a star in the constellation Ursa Major.
It is a yellow-hued class G8 subdwarf catalogued by British astronomer Stephen Groombridge with the Groombridge Transit Circle between 1806 and the 1830s and published posthumously in his star catalog, Catalogue of Circumpolar Stars (1838). Its high proper motion was noted by Friedrich Wilhelm Argelander in 1842.
It is 29.9 light-years (9.2 parsecs ) from the Sun as measured by the Gaia spacecraft, [1] which, as the distance is nearly 10 parsecs, means its absolute magnitude is almost equal to its apparent magnitude. It is a member of the galactic halo; such stars account for only 0.1 to 0.2 percent of the stars near the Sun. Like most halo stars, it has a low abundance of elements other than hydrogen and helium—what astronomers term a metal-poor star. [9]
Once suspected of being a binary star with a period of 175 days, current consensus is that it is single. Previous suspected observations of a stellar companion were probably "superflares"—analogous to the Sun's solar flares, but hundreds to millions of times more energetic. [9] [10] It had one of the first nine identified superflares.
When discovered, it had the highest proper motion of any star known, replacing 61 Cygni in that department. Later it dropped to second place after the discovery of Kapteyn's Star, and still later to third place after the discovery of Barnard's Star. It is considerably farther away than either of those stars, however, which means its transverse velocity is greater.
70 Ophiuchi is a binary star system located 16.6 light years away from the Earth. It is in the constellation Ophiuchus. At magnitude 4 it appears as a dim star visible to the unaided eye away from city lights.
Groombridge 1618 is a star in the northern constellation Ursa Major. With an apparent visual magnitude of +6.6, it lies at or below the threshold of stars visible to the naked eye for an average observer. It is relatively close to Earth, at 15.89 light-years (4.87 pc). This is a main sequence star of spectral type K7.5 Ve, having just 67% of the Sun's mass.
18 Scorpii is a solitary star located at a distance of some 46.1 light-years from the Sun at the northern edge of the Scorpius constellation. It has an apparent visual magnitude of 5.5, which is bright enough to be seen with the naked eye outside of urban areas. The star is drifting further away with a radial velocity of +11.6.
HR 7703 is a binary star system in the constellation of Sagittarius. The brighter component has an apparent visual magnitude of 5.31, which means it is visible from suburban skies at night. The two stars are separated by an angle of 7.10″, which corresponds to an estimated semimajor axis of 56.30 AU for their orbit.
Groombridge 34 is a binary star system in the northern constellation of Andromeda. It was listed as entry number 34 in A Catalogue of Circumpolar Stars, published posthumously in 1838 by British astronomer Stephen Groombridge. Based upon parallax measurements taken by the Gaia spacecraft, the system is located about 11.6 light-years from the Sun. This positions the pair among the nearest stars to the Solar System.
Beta Comae Berenices is a main sequence dwarf star in the northern constellation of Coma Berenices. It is located at a distance of about 29.95 light-years from Earth. The Greek letter beta (β) usually indicates that the star has the second highest visual magnitude in the constellation. However, with an apparent visual magnitude of 4.3, this star is actually slightly brighter than α Comae Berenices. It can be seen with the naked eye, but may be too dim to be viewed from a built-up urban area.
19 Aquilae is a single star located 142 light-years away from the Sun in the equatorial constellation of Aquila. 19 Aquilae is the Flamsteed designation. It is visible to the naked eye as a dim, yellow-white hued star with an apparent visual magnitude of 5.23. The star is moving closer to the Earth with a heliocentric radial velocity of −46.7 km/s.
Beta Canum Venaticorum, also named Chara, is a G-type main-sequence star in the northern constellation of Canes Venatici. At an apparent visual magnitude of 4.25, it is the second-brightest star in the constellation. Based upon an annual parallax shift of 118 mas, this star is 27.6 light-years distant from the Sun.
AD Leonis (Gliese 388) is a red dwarf star. It is located relatively near the Sun, at a distance of 16.2 light-years, in the constellation Leo. AD Leonis is a main sequence star with a spectral classification of M3.5V. It is a flare star that undergoes random increases in luminosity.
41 G. Arae, also known as GJ 666, is a trinary star system in the constellation Ara 28.7 light-years from the Sun. Although often called just 41 Arae, it is more accurate to call it 41 G. Arae, as the number 41 is the Gould designation.
HD 50281 is a star in the equatorial constellation of Monoceros. It is orange in hue with an apparent visual magnitude of 6.58, which lies at or below the typical limit of visibility to the naked eye. The star is located at a distance of 28.5 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −7.2 km/s.
HD 192310 is a star in the southern constellation of Capricornus. It is located in the solar neighborhood at a distance of 28.7 light-years, and is within the range of luminosity needed to be viewed from the Earth with the unaided eye. HD 192310 is suspected of being a variable star, but this is unconfirmed.
HD 115404 is a binary star system located in the constellation Coma Berenices. Parallax measurements made by Hipparcos put the system at 36 light-years, or 11 parsecs, away. The combined apparent magnitude of the system is 6.52, with the magnitudes of the components being 6.66 and 9.50.
36 Ursae Majoris is a double star in the northern constellation of Ursa Major. With an apparent visual magnitude of 4.8, it can be seen with the naked eye in suitable dark skies. Based upon parallax measurements, this binary lies at a distance of 42 light-years from Earth.
R Boötis is a variable star in the northern constellation of Boötes. Typically the star is too faint to be readily visible to the naked eye, with a brightness that fluctuates between apparent visual magnitudes of 9.98. The distance to this star is approximately 2,150 light years based on parallax measurements. It is drifting closer with a radial velocity of about −58 km/s.
HD 44594 is a star in the southern constellation Puppis. It has an apparent visual magnitude of 6.64, so it can be seen with the naked eye from the southern hemisphere under good viewing conditions. Based upon parallax measurements, it is located at a distance of 85 light-years from the Earth, giving it an absolute magnitude of 4.56.
10 Canum Venaticorum is the Flamsteed designation for an ordinary star in the northern constellation of Canes Venatici. It has an apparent visual magnitude of 5.95, which, according to the Bortle scale, can be faintly seen with the naked eye from suburban locations. Based upon an annual parallax shift of 0.057 arcseconds, this system is 57.26 light-years from Sun. It is drifting further away with a radial velocity of +80 km/s.
LHS 2090 is a red dwarf star of spectral type M6.5V, located in constellation Cancer at 20.8 light-years from Earth.
1 Delphini is the Flamsteed designation for a close binary star in the equatorial constellation Delphinus. With a combined apparent magnitude of 6.08, it is barely visible to the naked eye, even under ideal conditions. Parallax measurements put the components at a distance 703 and 780 light years respectively. However, its approaching the Solar System with a radial velocity of 15 km/s.