 A blue band light curve for CH Crucis, plotted from data published by Balona et al. (1992) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Crux |
| Right ascension | 12 41 56.56824 |
| Declination | −59° 41′ 08.9564″ |
| Apparent magnitude (V) | 4.91 |
| Characteristics | |
| Spectral type | B5III or B6IV |
| U−B color index | −0.37 |
| B−V color index | −0.044±0.03 |
| Variable type | γ Cas? |
| Astrometry | |
| Radial velocity (Rv) | +12.5±2.8 km/s |
| Proper motion (μ) | RA: -23.987 mas/yr Dec.: -4.110 mas/yr |
| Parallax (π) | 4.2068 ± 0.1651 mas |
| Distance | 780 ± 30 ly (238 ± 9 pc) |
| Absolute magnitude (MV) | −2.41 |
| Details | |
| Mass | 5.30±0.27 M☉ |
| Radius | 11.20±0.22 R☉ |
| Luminosity | 1,073 L☉ |
| Surface gravity (log g) | 2.90±0.03 cgs |
| Temperature | 10,600±106 K |
| Rotational velocity (v sin i) | 240 km/s |
| Age | 120 Myr |
| Other designations | |
| CH Cru, CPD−59° 4393, HD 110335, HIP 61966, HR 4823, SAO 240161, G 39 Crucis | |
| Database references | |
| SIMBAD | data |
CH Crucis is a solitary variable star in the southern constellation of Crux. It has the Gould designation 39 G. Crucis. The object is visible to the naked eye as a faint, blue-white hued point of light with an apparent visual magnitude that fluctuates around 4.91. The star is located approximately 780 light years distant from the Sun based on parallax, and is drifting further away with a radial velocity of about +12.5 km/s. It is a member of the nearby Sco OB2 association.
This is a conventional shell star, which is understood to be a Be star that is being viewed edge-on. Houk (1975) found a stellar classification of B5III, while Hiltner et al. assigned it to B6IV; suggesting it is a B-type star that is evolving off the main sequence. Samus et al. (2017) have tentatively classified it as a Gamma Cassiopeiae variable that ranges in brightness from magnitude 4.88 down to 5.7.
CH Crucis has 5.3 times the mass of the Sun and 11.2 times the Sun's radius. It is radiating 1,073 times the luminosity of the Sun from its photosphere at an effective temperature of 10,600 K. It is spinning rapidly with estimates of the projected rotational velocity ranging up to 240 or 250 km/s. This is giving the star an oblate shape with an equatorial bulge that is an estimated 18% larger than the polar radius.
References
- Balona, L. A.; Cuypers, J.; Marang, F. (February 1992). "Intensive photometry of southern Be variables. II. Summer objects". Astronomy & Astrophysics Supplement Series. 92: 533–563. Bibcode:1992A&AS...92..533B. Retrieved 18 December 2021.
- ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
- ^ Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 1, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1975mcts.book.....H.
- ^ Hiltner, W. A.; Garrison, R. F.; Schild, R. E. (July 1969), "MK Spectral Types for Bright Southern OB Stars", Astrophysical Journal, 157: 313–326, Bibcode:1969ApJ...157..313H, doi:10.1086/150069.
- "39 Crucis, a blue subgiant star in Crux", Ashland Astronomy Studio, archived from the original on 2013-04-14, retrieved 2012-08-23
- ^ Samus', N. N; Kazarovets, E. V; Durlevich, O. V; Kireeva, N. N; Pastukhova, E. N (2017), "General catalogue of variable stars: Version GCVS 5.1", Astronomy Reports, 61 (1): 80, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
- ^ Zorec, J.; et al. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy and Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
- ^ Arcos, C.; et al. (March 2018), "Stellar parameters and H α line profile variability of Be stars in the BeSOS survey", Monthly Notices of the Royal Astronomical Society, 474 (4): 5287–5299, arXiv:1711.08675, Bibcode:2018MNRAS.474.5287A, doi:10.1093/mnras/stx3075, S2CID 74872624.
- ^ Belle, G. T. (2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review, 20 (1): 51, arXiv:1204.2572, Bibcode:2012A&ARv..20...51V, doi:10.1007/s00159-012-0051-2, S2CID 119273474.
- "HIP 61966", Wolfram Alpha, retrieved 2012-08-23
- ^ Gould, Benjamin Apthorp (1879), "Uranometria Argentina catalog of bright southern stars", Resultados del Observatorio Nacional Argentino, 1, Bibcode:1879RNAO....1.....G, retrieved 2012-05-08.
- "CH Cru". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-08-15.
- Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- Hoogerwerf, Ronnie (March 2000), "OB association members in the ACT and TRC catalogues", Monthly Notices of the Royal Astronomical Society, 313 (1): 43–65, Bibcode:2000MNRAS.313...43H, doi:10.1046/j.1365-8711.2000.03192.x.
- ^ Rivinius, Th.; et al. (November 2006), "Bright Be-shell stars", Astronomy and Astrophysics, 459 (1): 137–145, Bibcode:2006A&A...459..137R, doi:10.1051/0004-6361:20053008.
| Constellation of Crux | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Stars |
| ||||||||||
| |||||||||||
| |||||||||||
| |||||||||||
 Category | |||||||||||