Gamma Trianguli
 Location of γ Trianguli (circled) |
|
| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Triangulum |
| Right ascension | 02h 17m 18.86703s[1] |
| Declination | +33° 50′ 49.8950″[1] |
| Apparent magnitude (V) | +4.01[2] |
| Characteristics | |
| Spectral type | A1Vnn[3] |
| U−B color index | +0.02[2] |
| B−V color index | +0.02[2] |
| Astrometry | |
| Radial velocity (Rv) | +9.9[4] km/s |
| Proper motion (μ) | RA: 44.64[1] mas/yr Dec.: –52.57[1] mas/yr |
| Parallax (π) | 29.04 ± 0.25[1] mas |
| Distance | 112.3 ± 1.0 ly (34.4 ± 0.3 pc) |
| Details | |
| Mass | 2.7[5] M☉ |
| Radius | 1.96[6] R☉ |
| Luminosity | 33.0[5] L☉ |
| Temperature | 9,440[7] K |
| Rotational velocity (v sin i) | 254[8] km/s |
| Age | 3.0 × 108[5] years |
| Other designations | |
Gamma Trianguli (Gamma Tri, γ Trianguli, γ Tri) is a star in the constellation Triangulum located approximately 112 light years from Earth. It has an apparent magnitude of +4.03 and forms an optical (line-of-sight) triple with Delta Trianguli and 7 Trianguli.[10]
This star has a stellar classification of A1Vnn,[3] which indicates it is an A-type main sequence star. It has 2.7[5] times the mass of the Sun and nearly double the Sun's radius.[6] Gamma Trianguli is radiating about 33[5] times the luminosity of the Sun from its outer envelope at an effective temperature of 9,440 K,[7] giving the star a white hue.[11] The star is roughly 300 million years old.[5]
It is rotating rapidly, with a projected rotational velocity of 254 km/s along the equator,[8] which causes the star to take the pronounced shape of an oblate spheroid like Altair.[10] Because the inclination of the star's axial tilt is unknown, this means that the azimuthal equatorial velocity is at least this amount and possibly higher.[8] By comparison, the Sun is a slow rotator with an equatorial azimuthal velocity of 2 km/s.[12] The doppler shift from the rapid rotation results in very diffuse absorption lines in the star's spectrum, as indicated by the 'nn' in the classification.[13]
Orbiting the star is a dusty debris disk with a combined mass of about 2.9 × 10−2 times the mass of the Earth. This disk can be detected because it is being heated to a temperature of about 75 K by Gamma Trianguli and is radiating this as infrared energy. The disk is separated from the host star by an angle of 2.24 arcseconds, corresponding to a physical radius of 80 AU, or 80 times the separation of the Earth from the Sun.[6]
Naming
In Chinese, 天大將軍 (Tiān Dà Jiāng Jūn), meaning Heaven's Great General, refers to an asterism consisting of γ Trianguli, γ Andromedae, φ Persei, 51 Andromedae, 49 Andromedae, χ Andromedae, υ Andromedae, τ Andromedae, 56 Andromedae, β Trianguli, and δ Trianguli. Consequently, γ Trianguli itself is known as 天大將軍十 (Tiān Dà Jiāng Jūn shí, English: the Tenth Star of Heaven's Great General.).[14]
See also
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Lua error in package.lua at line 80: module 'strict' not found. Note: see VizieR catalogue I/311.
- ↑ 2.0 2.1 2.2 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 3.0 3.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 6.0 6.1 6.2 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 7.0 7.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 8.0 8.1 8.2 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 10.0 10.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 10 日
