Gamma Trianguli
Template:Location mark Location of γ Trianguli (circled) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Triangulum |
| Right ascension | Template:RA[1] |
| Declination | Template:DEC[1] |
| Apparent magnitude (V) | +4.01[2] |
| Characteristics | |
| Spectral type | A1Vnn[3] |
| U−B Template:Engvar | +0.02[2] |
| B−V Template:Engvar | +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 mas[1] |
| Distance | Template:Rnd ± Template:Rnd ly (Template:Rnd ± Template:Rnd pc) |
| Absolute magnitude (MV) | +1.35[5] |
| Details | |
| Mass | 2.7[6] Template:Solar mass |
| Radius | 1.96[7] Template:Solar radius |
| Luminosity | 33.0[6] Template:Solar luminosity |
| Temperature | 9,440[8] K |
| Rotational velocity (v sin i) | 254[9] km/s |
| Age | 300[6] Myr |
| Metallicity [Fe/H] | {{{metal_fe2}}} dex |
| Other designations | |
| γ Trianguli, γ Tri, Gamma Tri, 9 Trianguli, BD+33 397, FK5 79, HD 14055, HIP 10670, HR 664, SAO 55427[10] | |
| Database references | |
| SIMBAD | data |
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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 +4.01 and forms an optical (line-of-sight) triple with Delta Trianguli and 7 Trianguli.[11]
Properties
This star has a stellar classification of A1Vnn,[3] which indicates it is an A-type main sequence star. It has 2.7[6] times the mass of the Sun and nearly double the Sun's radius.[7] Gamma Trianguli is radiating about 33[6] times the luminosity of the Sun from its outer envelope at an effective temperature of 9,440 K,[8] giving the star a white hue.[12] The star is roughly 300 million years old.[6]
Rotation
It is rotating rapidly, with a projected rotational velocity of 254 km/s along the equator,[9] which causes the star to take the pronounced shape of an oblate spheroid like Altair.[11] 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.[9] By comparison, the Sun is a slow rotator with an equatorial azimuthal velocity of 2 km/s.[13] 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.[14]
Debris disk
Template:CSS image crop 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.[7]
Naming
In Chinese, Script error: No such module "Lang". (Script error: No such module "Lang".), 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, the Chinese name for γ Trianguli itself is Script error: No such module "Lang". (Script error: No such module "Lang"., Template:Langx.).[15]
References
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- ↑ Template:In lang AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 10 日 Template:Webarchive
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