Beta Apodis
Star in the constellation Apus
From Wikipedia, the free encyclopedia
Beta Apodis is a star in the southern circumpolar constellation of Apus. Its identifier is a Bayer designation that is Latinized from β Apodis, and abbreviated Bet Aps or β Aps, respectively. The apparent visual magnitude of this star is +4.24,[2] which is bright enough to be seen with the naked eye. It is located at a distance of approximately 156 light-years (48 parsecs) from Earth,[1] as determined by parallax measurements. The star is drifting closer with a heliocentric radial velocity of −30 km/s.[5]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Apus |
| Right ascension | 16h 43m 04.659s[1] |
| Declination | −77° 31′ 02.76″[1] |
| Apparent magnitude (V) | +4.24[2] |
| Characteristics | |
| Evolutionary stage | red clump[3] |
| Spectral type | K0 III[4] |
| U−B color index | +0.95[2] |
| B−V color index | +1.06[2] |
| Astrometry | |
| Radial velocity (Rv) | −30.3±0.7[5] km/s |
| Proper motion (μ) | RA: −281.986 mas/yr[1] Dec.: −354.837 mas/yr[1] |
| Parallax (π) | 20.9535±0.1597 mas[1] |
| Distance | 156 ± 1 ly (47.7 ± 0.4 pc) |
| Absolute magnitude (MV) | 0.819[3] |
| Details | |
| Mass | 1.84[3] M☉ |
| Radius | 11[6] R☉ |
| Luminosity | 50[6] L☉ |
| Surface gravity (log g) | 2.82±0.18[7] cgs |
| Temperature | 4,855±112[7] K |
| Metallicity [Fe/H] | –0.03±0.04[7] dex |
| Rotational velocity (v sin i) | 1.3[8] km/s |
| Other designations | |
| β Aps, β Apodis, CPD−77 1221, FK5 3319, HD 149324, HIP 81852, HR 6163, SAO 257424[9] | |
| Database references | |
| SIMBAD | data |
The spectrum of this star matches a stellar classification of K0 III,[4] which, according to models of stellar evolution, indicates that it is in the giant star stage, having exhausted the supply of hydrogen at its core. The measured angular diameter of this star is 2.09±0.11 mas.[10] At the estimated distance of this star, this yields a physical size of about 11 times the radius of the Sun.[11] The expanded outer atmosphere of Beta Apodis has an effective temperature of about 4,855 K.[7] This heat is causing it to glow with the characteristic orange hue of a K-type star.[12]
Naming
In Chinese caused by adaptation of the European southern hemisphere constellations into the Chinese system, 異雀 (Yì Què), meaning Exotic Bird, refers to an asterism consisting of β Apodis, ζ Apodis, ι Apodis, γ Apodis, δ Octantis, δ1 Apodis, η Apodis, α Apodis and ε Apodis. Consequently, β Apodis itself is known as 異雀三 (Yì Què sān, English: the Third Star of Exotic Bird.)[13]
