PV Telescopii
PV Telescopii, also known as HD 168476, is a variable star in the southern constellation of Telescopium. It is too dim to be visible to the naked eye, having an apparent visual magnitude that has been measured varying from 9.24 down to 9.40. The star is the prototype of a class of objects called PV Telescopii variables. It is located at an estimated distance of approximately 23 kilolight-years (7.1 kiloparsecs) from the Sun, but is drifting closer with a radial velocity of −169 km/s.
A light curve for PV Telescopii, adapted from Jeffery et al. (2020) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Telescopium |
| Right ascension | 18h 23m 14.66203s |
| Declination | −56° 37′ 44.1401″ |
| Apparent magnitude (V) | 9.30 (9.24 - 9.40) |
| Characteristics | |
| Spectral type | B5p |
| U−B color index | −0.60 |
| B−V color index | −0.10 |
| Variable type | PV Tel |
| Astrometry | |
| Radial velocity (Rv) | −169 km/s |
| Proper motion (μ) | RA: −1.086 mas/yr Dec.: −7.705 mas/yr |
| Parallax (π) | 0.1162 ± 0.0449 mas |
| Distance | 23,000 ly (7,100+1,400 −2,000 pc) |
| Absolute magnitude (MV) | −4.4 |
| Details | |
| Mass | 0.94 M☉ |
| Radius | 27.20+4.09 −7.26 R☉ |
| Luminosity | 24,000+8,600 −9,900 L☉ |
| Surface gravity (log g) | 1.60±0.25 cgs |
| Temperature | 13,750±400 K |
| Metallicity [Fe/H] | −0.15 dex |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is an extreme helium star that shows a highly-processed atmosphere. It is a blue-white hued B-type supergiant star with a peculiar spectrum that has "weak hydrogen lines and enhanced lines of He and C". This object may be a late thermal pulse post-AGB star or the result of a merger of two white dwarf stars. The star shows radial velocity changes thought to be due to radial pulsations caused by a strange mode instability. It shows variations over a few days, 8–10 days being typically quoted. Despite a mass thought to be less than the sun, it is actually around 24,000 more luminous.