Alpha Volantis
Binary star system in the constellation Volans
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Alpha Volantis (Alpha Vol), Latinized from α Volantis, is a binary star[12] system located in the southern constellation Volans. It has an apparent visual magnitude of +4.00, which is bright enough to be seen with the naked eye. Based upon parallax measurements made with the Hipparcos spacecraft, it is located at a distance of 125 light years from the Sun. As of 2010, the two components of this system had an angular separation of 0.0318″ along a position angle of 286.9°. The magnitude difference between the two components is 0.1.[13] It is considered a member of the Sirius supercluster.[5]
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Volans |
| Right ascension | 09h 02m 26.79592s[1] |
| Declination | −66° 23′ 45.8727″[1] |
| Apparent magnitude (V) | +4.00[2] |
| Characteristics | |
| Spectral type | kA3hA5mA5 V[3] |
| U−B color index | +0.13[2] |
| B−V color index | +0.14[2] |
| Astrometry | |
| Radial velocity (Rv) | +4.9[4] km/s |
| Proper motion (μ) | RA: −2.00[1] mas/yr Dec.: +95.51[1] mas/yr |
| Parallax (π) | 26.11±0.12 mas[1] |
| Distance | 124.9 ± 0.6 ly (38.3 ± 0.2 pc) |
| Absolute magnitude (MV) | +1.60[5] |
| Orbit[6] | |
| Period (P) | 0.652 ± 0.001 yr |
| Semi-major axis (a) | 0.0321 ± 0.0013″ |
| Eccentricity (e) | 0.041 ± 0.038 |
| Inclination (i) | 101.9 ± 2.3° |
| Longitude of the node (Ω) | 105.3 ± 1.4° |
| Periastron epoch (T) | 2015.593 ± 0.063 |
| Argument of periastron (ω) (secondary) | 248.5 ± 34.2° |
| Details | |
| Mass | 1.87[7] M☉ |
| Radius | 1.9[8] R☉ |
| Surface gravity (log g) | 4.09[3] cgs |
| Temperature | 8,198[3] K |
| Metallicity [Fe/H] | +0.19[3] dex |
| Rotational velocity (v sin i) | 30.6±0.4[9] km/s |
| Age | 427+183 −377[10] Myr |
| Other designations | |
| CPD−65°1065, FK5 343, GJ 333.3, GJ 9284, HD 78045, HIP 44382, HR 3615, SAO 250422[11] | |
| Database references | |
| SIMBAD | data |
The primary component is an Am star with a stellar classification of kA3hA5mA5 V.[3] This notation indicates the star has the weak calcium II K-line of an A3 star, and the hydrogen and metallic lines of an A5 star.[14] It has an estimated age of 427 million years.[10] In 1992, it was found to be emitting an infrared excess, suggesting the presence of a circumstellar disk of dust.[15] However, subsequent observations have not confirmed this.[16]