Kappa1 Apodis
Star in the constellation Apus
From Wikipedia, the free encyclopedia
Kappa1 Apodis is a binary star[4] system in the southern circumpolar constellation of Apus.[1] Its idetifier is a Bayer designation that is Latinized from κ1 Apodis, and abbreviated Kap1 Aps or κ1 Aps, respectively. Based upon parallax measurements, it is located roughly 1,060 light-years (325 parsecs) from Earth. The combined apparent visual magnitude of the system is 5.52,[3] indicating that this is a faint, naked eye star that can be viewed in dark suburban skies. It is moving away from the Sun with a radial velocity of +62 km/s.[7]
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Apus[1] |
| Right ascension | 15h 31m 30.82213s[2] |
| Declination | −73° 23′ 22.5295″[2] |
| Apparent magnitude (V) | 5.52[3] |
| Characteristics | |
| Spectral type | B1npe[4] + sdO[5] |
| U−B color index | −0.791[3] |
| B−V color index | −0.128[3] |
| Variable type | γ Cas[6] |
| Astrometry | |
| Radial velocity (Rv) | +62[7] km/s |
| Proper motion (μ) | RA: +0.996 mas/yr[2] Dec.: −18.345 mas/yr[2] |
| Parallax (π) | 3.0798±0.0717 mas[2] |
| Distance | 1,060 ± 20 ly (325 ± 8 pc) |
| Absolute magnitude (MV) | −2.47[1] |
| Orbit[8] | |
| Period (P) | 192.1±0.1 d |
| Semi-major axis (a) | ≥ 288.3±8.4 R☉ |
| Eccentricity (e) | 0 (assumed) |
| Inclination (i) | 60±4° |
| Periastron epoch (T) | 2458401.9±2.2 HJD |
| Semi-amplitude (K1) (primary) | 9.09±0.08 km/s |
| Semi-amplitude (K2) (secondary) | 66.87±1.84 km/s |
| Details | |
| A | |
| Mass | 11.8±1.0[8] M☉ |
| Radius | 5.45±0.29[5] R☉ |
| Luminosity | 11,117[8] L☉ |
| Surface gravity (log g) | 4.01[8] cgs |
| Temperature | 24,000[8] K |
| Rotational velocity (v sin i) | 250[5] km/s |
| Age | 19.5[8] Myr |
| B | |
| Mass | 1.60±0.14[8] M☉ |
| Radius | 0.44±0.06[5] R☉ |
| Luminosity | 446[5] L☉ |
| Temperature | 40,000[5] K |
| Other designations | |
| κ1 Apodis, κ1 Aps, Kap1 Aps, CD−72°1139, CPD−72°1802, FK5 567, HD 137387, HIP 76013, HR 5730, SAO 257289, WDS J15315-7323A[9] | |
| Database references | |
| SIMBAD | data |
This is a spectroscopic binary system, made up of a Be star and a subdwarf O star, which complete an orbit around each other every 192 days.[8] The combined spectrum matches a stellar classification of B1npe.[4] The 'e' suffix indicates that this is a Be star with emission lines in the spectrum. An 'n' means that the absorption lines in the spectrum are broadened from the Doppler effect as a result of rapid rotation. Finally, the 'p' shows some peculiarity in the spectrum. It is classified as a Gamma Cassiopeiae type variable star and its brightness varies from magnitude +5.43 to +5.61.
This is a runaway star with a peculiar velocity of 69.8±4.7 km/s.[11] Because it is a binary star system, it was most likely not turned into a runaway system as the result of a supernova explosion.[4]
A 12th-magnitude orange K-type subgiant[12] located at an angular separation of 27 arcseconds has a much smaller parallax than Kappa1 Apodis and is a distant background object.[13]