Gamma Trianguli Australis
 Location of γ Trianguli Australis (circled) |
|
| Observation data Epoch J2000.0 Equinox J2000.0 |
|
|---|---|
| Constellation | Triangulum Australe |
| Right ascension | 15h 18m 54.58198s[1] |
| Declination | –68° 40′ 46.3654″[1] |
| Apparent magnitude (V) | +2.87[2] |
| Characteristics | |
| Spectral type | A1 V[3][4] |
| U−B color index | –0.02[5] |
| B−V color index | +0.00[5] |
| Astrometry | |
| Radial velocity (Rv) | –3.0[2] km/s |
| Proper motion (μ) | RA: –66.58[1] mas/yr Dec.: –32.31[1] mas/yr |
| Parallax (π) | 17.74 ± 0.12[1] mas |
| Distance | 184 ± 1 ly (56.4 ± 0.4 pc) |
| Details | |
| Radius | 5.86[6] R☉ |
| Temperature | 9,400[6] K |
| Rotational velocity (v sin i) | 199[4] km/s |
| Age | 260[7] Myr |
| Other designations | |
Gamma Trianguli Australis (γ TrA, γ Trianguli Australis) is a star in the constellation Triangulum Australe. Along with Alpha and Beta Trianguli Australis it forms a prominent triangular asterism that gives the constellation its name (Latin for southern triangle). It is the third brightest member of this constellation with an apparent visual magnitude of +2.87.[2] based upon parallax measurements, Gamma Trianguli Australis is located at a distance of about 184 light-years (56 parsecs) from Earth.[1]
The spectrum of this star matches a stellar classification of A1 V,[3][4] which identifies it as an A-type main sequence star that is generating energy through the nuclear fusion of hydrogen at its core. An unusual abundance of the element europium demonstrates it to be a peculiar, or Ap star.[9] Most stars of this type are slow rotators,[10] but Gamma Trianguli Australis displays a very high rate of rotation with a projected rotational velocity of 199 km s−1.[4] It has an estimated age of 260 million years.[7]
This system shows an excess emission of infrared radiation, suggesting that there is a circumstellar disk of dust orbiting this star. The mean temperature of the emission is 50 K, corresponding to a separation from the star of 481 AU.[6]
Modern legacy
γ TrA appears on the flag of Brazil, symbolising the state of Paraná.[11]
References
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