Astronomy:Theta2 Crucis

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Short description: Star in the constellation Crux


θ2 Crucis
Location of θ2 Crucis (circled in red)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Crux
Right ascension  12h 04m 19.22008s[1]
Declination −63° 09′ 56.5167″[1]
Apparent magnitude (V) 4.70 - 4.74[2]
Characteristics
Spectral type B3 V[3]
U−B color index −0.61[4]
B−V color index −0.08[4]
Variable type β Cep[2]
Astrometry
Radial velocity (Rv)+16.3[5] km/s
Proper motion (μ) RA: −18.467[1] mas/yr
Dec.: +0.467[1] mas/yr
Parallax (π)4.7314 ± 0.1276[1] mas
Distance690 ± 20 ly
(211 ± 6 pc)
Absolute magnitude (MV)−2.35[6]
Orbit[7]
Period (P)3.428 d
Eccentricity (e)0.00
Periastron epoch (T)2419604.367 JD
Semi-amplitude (K1)
(primary)
51.3 km/s
Details
Mass5.9[1] M
Radius6.9[1] R
Luminosity1,935[1] L
Surface gravity (log g)3.55[1] cgs
Temperature15,361[1] K
Metallicity [Fe/H]+0.20[1] dex
Rotational velocity (v sin i)23[8] km/s
Age18.5[9] Myr
Other designations
θ2 Cru, CD−62°610, HD 104841, HIP 58867, HR 4603, SAO 251717[10]
Database references
SIMBADdata

Theta2 Crucis, Latinized from θ2 Crucis, is a spectroscopic binary star in the constellation Crux. This pair of stars complete an orbit every 3.4280 days and they have a low orbital eccentricity that is close to 0.0.[11] Theta2 Crucis is located at about 690 light-years from the Sun.

A light curve for Theta2 Crucis, plotted from TESS data[12]

Since a member of the system is a β Cephei-type variable star, the magnitude is not fixed but varies slightly between +4.70 and +4.74. The period of this variability is 0.0889 days.[2] The system is categorized as is a blue-white B-type main sequence star with a stellar classification of B3 V,[3] although it has also been classified as a subgiant.[13] Evolutionary models show it at a late stage of its main sequence life.[1]

References

  1. 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  2. 2.0 2.1 2.2 Samus, N. N.; Durlevich, O. V. (January 2009). "General Catalogue of Variable Stars". VizieR. http://cdsarc.u-strasbg.fr/viz-bin/Cat?cat=B/gcvs&. Retrieved 2010-05-19.  Note: query for GCVS "tet 2 Cru".
  3. 3.0 3.1 Houk, N.; Cowley, A. P. (1975), University of Michigan Catalogue of two-dimensional spectral types for the HD stars, 1, Bibcode1975mcts.book.....H. 
  4. 4.0 4.1 Johnson, H. L.; Iriarte, B.; Mitchell, R. I.; Wisniewskj, W. Z. (1966). "UBVRIJKL photometry of the bright stars". Communications of the Lunar and Planetary Laboratory 4 (99): 99. Bibcode1966CoLPL...4...99J. 
  5. Wilson, Ralph Elmer (1953). "General Catalogue of Stellar Radial Velocities". Carnegie Institute Washington D.C. Publication (Washington: Carnegie Institution of Washington). Bibcode1953GCRV..C......0W. 
  6. Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode2012AstL...38..331A. 
  7. Pourbaix, D.; Tokovinin, A. A.; Batten, A. H.; Fekel, F. C.; Hartkopf, W. I. et al. (2004), "SB9: The ninth catalogue of spectroscopic binary orbits", Astronomy & Astrophysics 424 (2): 727–732, doi:10.1051/0004-6361:20041213, Bibcode2004A&A...424..727P. 
  8. Bernacca, P. L.; Perinotto, M. (1970). "A catalogue of stellar rotational velocities". Contributi Osservatorio Astronomico di Padova in Asiago 239 (1): 1. Bibcode1970CoAsi.239....1B. 
  9. Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society 410 (1): 190–200, doi:10.1111/j.1365-2966.2010.17434.x, Bibcode2011MNRAS.410..190T 
  10. "V* tet02 Cru". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=V%2A+tet02+Cru. 
  11. Batten, A. H. (1967). "Sixth catalogue of the orbital elements of spectroscopic binary systems". Publications of the Dominion Astrophysical Observatory, Victoria 13: 154–155. Bibcode1967PDAO...13..119B. 
  12. "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html. 
  13. Skiff, B. A. (2014). "VizieR Online Data Catalog: Catalogue of Stellar Spectral Classifications (Skiff, 2009-2016)". VizieR On-line Data Catalog: B/Mk. Originally Published in: Lowell Observatory (October 2014) 1. Bibcode2014yCat....1.2023S.