V692 Coronae Australis
From Wikipedia, the free encyclopedia
  | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Corona Australis |
| Right ascension | 18h 13m 12.69843s[1] |
| Declination | −41° 20′ 09.9972″[1] |
| Apparent magnitude (V) | 5.46 - 5.51[2] |
| Characteristics | |
| Spectral type | B2 III[3] or B1.5 IIIp[4] |
| B−V color index | −0.17[5] |
| Variable type | SX Arietis[6] |
| Astrometry | |
| Radial velocity (Rv) | −15.3±2.8[7] km/s |
| Proper motion (μ) | RA: −2.050 mas/yr[1] Dec.: −6.210 mas/yr[1] |
| Parallax (π) | 1.7423±0.0977 mas[1] |
| Distance | 1,900 ± 100 ly (570 ± 30 pc) |
| Absolute magnitude (MV) | −6.44[8] or −2.26[9] |
| Details | |
| Mass | 7.35±0.48[10] M☉ |
| Radius | 12.6±0.7[11] R☉ |
| Luminosity (bolometric) | 4,181[10] L☉ |
| Surface gravity (log g) | 3.52+0.33 −0.14[1] cgs |
| Temperature | 17,061+1,474 −1,357[12] K |
| Rotational velocity (v sin i) | 212±9[13] km/s |
| Age | 31.6±5.1[14] Myr |
| Other designations | |
| 3 G. Corona Australis[15], V692 CrA, CD−41°12534, CPD−41°8620, GC 24824, HD 166596, HIP 89290, HR 6804, SAO 228815[16] | |
| Database references | |
| SIMBAD | data |
V692 Coronae Australis (HD 166596; HR 6804; 3 G. CrA), or simply V692 CrA, is a whitish-blue hued variable star located in the southern constellation Corona Australis. It has a maximum apparent magnitude of around 5.5, making it faintly visible to the naked eye. The object is located relatively far at a distance of approximately 1,900 light years based on Gaia DR3 parallax measurements,[1] but it is approaching the Solar System with a fairly constrained heliocentric radial velocity of −15.3 km/s.[7] At its current distance, V692 CrA's brightness is heavily diminished by 0.46 magnitudes due to extinction due to interstellar dust.[17] Its absolute magnitude depends on the source: Westin (1985) gave a value of −6.44[8] while the extended Hipparcos catalogue gave a value of −2.26.[9]
Astronomers Carlos and Mercedes Jaschek along with a colleague listed HD 166596 as a Be star in 1964.[19] However, its status as an Ap star was not observed until 1979 by astronomers N. Vogt and A.M Faundez.[20] A year later, HD 166596 was observed to be variable and it had a period of 1.67 days.[21] In 1981, its variability was confirmed and it was given the variable star designation V692 Coronae Australis—the 692nd variable star in Corona Australis.[22] The star might have a shorter period of 49.8 hours.[6]
V692 CrA has a stellar classification of B2 III[3] or B1.5 IIIp,[4] both indicating that it is a slightly evolved B-type giant star. The second classification indicates that V692 CrA has peculiarities in its spectrum. It has 7.35 times the mass of the Sun[10] and 12.6 times the Sun's radius.[11] It radiates at a bolometric luminosity 4,181 times that of the Sun[10] from its photosphere at an effective temperature of 17,061 K.[12] V692 CrA is estimated to be 31.6 million years old[14] and it spins rapidly with a projected rotational velocity of 212 km/s.[13]
