XX Pyxidis
| 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 | |
| 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 | |
| Database references | |
| SIMBAD | data |
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.
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]
References
[edit]- ^ Arentoft, T.; Sterken, C.; Handler, G. (September 2001). "Low-frequency variability and binarity of the δ Scuti star XX Pyx". Monthly Notices of the Royal Astronomical Society. 326 (1): 192–202. Bibcode:2001MNRAS.326..192A. doi:10.1046/j.1365-8711.2001.04594.x.
- ^ a b c d e f g h i j k Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1: B/gcvs. Bibcode:2009yCat....102025S.
- ^ a b c d e f g Aerts, C.; Handler, G.; Arentoft, T.; Vandenbussche, B.; Medupe, R.; Sterken, C. (2002). "The δ Scuti star XX Pyx is an ellipsoidal variable". Monthly Notices of the Royal Astronomical Society. 333 (2): L35–L39. Bibcode:2002MNRAS.333L..35A. doi:10.1046/j.1365-8711.2002.05627.x.
- ^ Chang, S.-W.; et al. (2013). "Statistical Properties of Galactic δ Scuti Stars: Revisited". The Astronomical Journal. 145 (5): 10. arXiv:1303.1031. Bibcode:2013AJ....145..132C. doi:10.1088/0004-6256/145/5/132. S2CID 118900730. 132.
- ^ "XX Pyxidis". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 5 September 2015.
- ^ Templeton, Matthew (16 July 2010). "Delta Scuti and the Delta Scuti Variables". Variable Star of the Season. AAVSO (American Association of Variable Star Observers). Retrieved 5 September 2015.
- ^ Bedding, Timothy R.; et al. (2020). "Very regular high-frequency pulsation modes in young intermediate-mass stars". Nature. 581 (7807): 147–151. arXiv:2005.06157. Bibcode:2020Natur.581..147B. doi:10.1038/s41586-020-2226-8. PMID 32405022. S2CID 218613877.
