CH Crucis
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Crux |
| Right ascension | 12h 41m 56.56824s[2] |
| Declination | −59° 41′ 08.9564″[2] |
| Apparent magnitude (V) | 4.91[3] |
| Characteristics | |
| Spectral type | B5III[4] or B6IV[5] |
| U−B color index | −0.37[6] |
| B−V color index | −0.044±0.03[3] |
| Variable type | γ Cas?[7] |
| Astrometry | |
| Radial velocity (Rv) | +12.5±2.8[3] km/s |
| Proper motion (μ) | RA: -23.987[2] mas/yr Dec.: -4.110[2] mas/yr |
| Parallax (π) | 4.2068 ± 0.1651 mas[2] |
| Distance | 780 ± 30 ly (238 ± 9 pc) |
| Absolute magnitude (MV) | −2.41[3] |
| Details | |
| Mass | 5.30±0.27[8] M☉ |
| Radius | 11.20±0.22[9] R☉ |
| Luminosity | 1,073[3] L☉ |
| Surface gravity (log g) | 2.90±0.03[9] cgs |
| Temperature | 10,600±106[9] K |
| Rotational velocity (v sin i) | 240[10] km/s |
| Age | 120[11][better source needed] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
CH Crucis is a solitary[14] variable star in the southern constellation of Crux. It has the Gould designation 39 G. Crucis.[12] 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.[3] The star is located approximately 780 light years distant from the Sun based on parallax,[2] and is drifting further away with a radial velocity of about +12.5 km/s.[3] It is a member of the nearby Sco OB2 association.[15]
This is a conventional shell star, which is understood to be a Be star that is being viewed edge-on.[16] Houk (1975) found a stellar classification of B5III,[4] while Hiltner et al. assigned it to B6IV;[5] suggesting it is a B-type star that is evolving off the main sequence.[8] 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.[7]
CH Crucis has 5.3[8] times the mass of the Sun and 11.2[9] times the Sun's radius. It is radiating 1,073[3] times the luminosity of the Sun from its photosphere at an effective temperature of 10,600 K.[9] It is spinning rapidly with estimates of the projected rotational velocity ranging up to 240 or 250 km/s.[16][10] This is giving the star an oblate shape with an equatorial bulge that is an estimated 18% larger than the polar radius.[10]
References
[edit]- ^ 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.
- ^ a b c d e f 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.
- ^ a b c d e f g h 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.
- ^ a b 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.
- ^ a b 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
- ^ a b 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.
- ^ a b c 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.
- ^ a b c d e 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.
- ^ a b c 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
- ^ a b 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.
- ^ a b 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.
