X Caeli

This article is about γ² Caeli. For other stars with this Bayer designation, see γ Caeli.

X Caeli, or Gamma² Caeli, is a binary star system in the southern constellation of Caelum. It is barely visible to the naked eye with an apparent visual magnitude of 6.32.^[5] based upon an annual parallax shift of 9.6 mas,^[1] it is located 341 light-years from Earth. The system is moving further away with a heliocentric radial velocity of +6 km/s.^[7]

A visual-band light curve for X Caeli, adapted from Mantegazza and Poretti (1996)^[12]

X Caeli

The constellation Caelum near the horizon, with the four main stars marked by a line
Observation data Epoch J2000      Equinox J2000
Constellation	Caelum
Right ascension	05h 04m 26.19316s[1]
Declination	−35° 42′ 17.7574″[1]
Apparent magnitude (V)	6.28 – 6.39[2] (6.43 + 9.65)[3]
Characteristics
Spectral type	F2 IV/V[4]
B−V color index	0.311±0.006[5]
Variable type	δ Sct[6]
Astrometry
Radial velocity (Rv)	+6.4±0.8[7] km/s
Proper motion (μ)	RA: +28.39[8] mas/yr Dec.: +41.71[8] mas/yr
Parallax (π)	9.5567 ± 0.0583 mas[1]
Distance	341 ± 2 ly (104.6 ± 0.6 pc)
Absolute magnitude (MV)	1.36[5]
Details
Mass	1.52[9] M☉
Radius	3.43±0.32[10] R☉
Luminosity	23.65[5] L☉
Surface gravity (log g)	3.80[9] cgs
Temperature	7,227±246[9] K
Rotational velocity (v sin i)	69.0±1.0[10] km/s
Age	961[9] Myr
Other designations
γ2 Cae, γ2 Caeli, X Caeli, BD+27°2400, GC 6214, HD 32846, HIP 23596, HR 1653, SAO 195534, CCDM 05044-3542, WDS J05044-3542AB[11]
Database references
SIMBAD	data

The yellow-white-hued primary, component A, has an apparent magnitude of +6.32 and stellar classification of F2 IV/V,^[4] showing mixed traits of an F-type main-sequence star and a subgiant. It is classified as a Delta Scuti-type variable star and its brightness varies from magnitude +6.28 to +6.39 with a period of 3.25 hours. A 2000 observing campaign identified at least six independent pulsation modes for this variation.^[10] The companion star, component B, has an apparent magnitude of +9.65 and, as of 2000, is at an angular separation of 0.890″ along a position angle of 183°.^[3]

References

1. 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.
2. VSX:Detail for X Cae, retrieved 2018-08-24.
3. Fabricius, C.; Makarov, V. V. (April 2000), "Two-colour photometry for 9473 components of close Hipparcos double and multiple stars", Astronomy and Astrophysics, 356: 141–145, Bibcode:2000A&A...356..141F.
4. Houk, Nancy (1979), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 3, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan, Bibcode:1982mcts.book.....H.
5. 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.
6. 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): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
7. Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065, S2CID 119231169.
8. van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
9. David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146, S2CID 33401607.
10. Mantegazza, L.; et al. (February 2000), "Simultaneous intensive photometry and high resolution spectroscopy of delta Scuti stars. IV. An improved picture of the pulsational behaviour of X Caeli", Astronomy and Astrophysics, 354: 112–124, arXiv:astro-ph/9911337, Bibcode:2000A&A...354..112M.
11. "HD 32846". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 24 August 2018.
12. Mantegazza, L.; Poretti, E. (August 1996), "Simultaneous intensive photometry and high resolution spectroscopy of δ Scuti stars. II. X Caeli: a star with unusual spectral features", Astronomy & Astrophysics, 312: 855–864, Bibcode:1996A&A...312..855M.

External links

• HR 1653
• Image Gamma2 Caeli