XX Pyxidis
Star in the constellation Pyxis
From Wikipedia, the free encyclopedia
XX Pyxidis is a star located in the constellation Pyxis. It has an apparent magnitude that varies slightly at about 11.5, and is about 2,300 light years away.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Pyxis |
| Right ascension | 08h 58m 39.03s[2] |
| Declination | −24° 35′ 10.6″[2] |
| Apparent magnitude (V) | 11.49[3] |
| Characteristics | |
| Evolutionary stage | main sequence[2] |
| Spectral type | A4V + M3V[4] |
| Variable type | Delta Scuti variable[3] |
| Astrometry | |
| Proper motion (μ) | RA: −13.830[2] mas/yr Dec.: +6.985[2] mas/yr |
| Parallax (π) | 1.4301±0.0341 mas[2] |
| Distance | 2,280 ± 50 ly (700 ± 20 pc) |
| Orbit[4] | |
| Period (P) | 1.15 d |
| Eccentricity (e) | 0.0 |
| Inclination (i) | 25-30° |
| Semi-amplitude (K1) (primary) | 17.8±0.4 km/s |
| Details | |
| Hot star | |
| Mass | 1.85±0.05[4] M☉ |
| Radius | 1.9[2] R☉ |
| Luminosity | 27[2] L☉ |
| Surface gravity (log g) | 4.21[2] cgs |
| Temperature | 9,431[2] K |
| Metallicity [Fe/H] | +0.09[2] dex |
| Rotation | 1.5 d[4] |
| Rotational velocity (v sin i) | 52[5] km/s |
| Age | 316[2] Myr |
| Cool star | |
| Mass | 0.3[4] M☉ |
| Other designations | |
| XX Pyxidis, CD−24 7599, GSC 06589-00261[6] | |
| Database references | |
| SIMBAD | data |
XX Pyxidis is one of the more-studied members of a class of stars known as Delta Scuti variables[4]—short-period (six hours at most) pulsating stars that have been used as standard candles and as subjects to study astroseismology.[7] Astronomers made more sense of its pulsations when it became clear that it is also a binary star system. The main star is a white main sequence star of spectral type A4V that is around 1.85±0.05 times as massive as the Sun. Its companion is most likely a red dwarf star of spectral type M3V, around 0.3 times as massive as the Sun. The two are very close—possibly only 3 times the diameter of the Sun between them—and orbit each other every 1.15 days. The brighter star is deformed into an egg-shape,[4] and pulsates in several overlapping modes 26-76 times per day.[8]