Theta² Crucis

θ2 Crucis
Observation data
Epoch J2000      Equinox J2000
Constellation Crux
Right ascension 12h 04m 19.2155s[1]
Declination −63° 09′ 56.559″[1]
Apparent magnitude (V) 4.718[2]
Characteristics
Spectral type B2IV[2]
U−B color index −0.61[3]
B−V color index −0.08[3]
Variable type Beta Cephei variable
Astrometry
Radial velocity (Rv) +16.3[4] km/s
Proper motion (μ) RA: −17.19[1] mas/yr
Dec.: −0.01[1] mas/yr
Parallax (π) 4.33 ± 0.53[1] mas
Distance approx. 750 ly
(approx. 230 pc)
Details
Rotational velocity (v sin i) 23[5] km/s
Other designations
HR 4603, CD-62 610, HD 104841, SAO 251717, HIP 58867.[2]

θ2 Crucis (θ2 Cru / Theta2 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.[6] θ2 Crucis is located at about 750 light-years from the Sun.[1]

The system has a combined mean apparent magnitude of +4.72m. Since a member of the system is a β Cephei-type variable star, the magnitude is not fixed but varies slightly between +4.70m and +4.74m. The period of this variability is 0.0889 days.[7] The system is categorized as is a blue-white subgiant with a stellar classification of B2 IV.

References

  1. ^ a b c d e f Perryman, M. A. C.; et al. (April 1997). "The HIPPARCOS Catalogue". Astronomy & Astrophysics 323: L49–L52. Bibcode 1997A&A...323L..49P. 
  2. ^ a b c "V* tet02 Cru -- Spectroscopic binary". SIMBAD Astronomical Database. Centre de Données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=V*+tet02+Cru. Retrieved 2010-05-19. 
  3. ^ a b 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). Bibcode 1966CoLPL...4...99J. 
  4. ^ Wilson, Ralph Elmer (1953). General Catalogue of Stellar Radial Velocities. Washington: Carnegie Institution of Washington. Bibcode 1953QB901.W495...... 
  5. ^ Bernacca, P. L.; Perinotto, M. (1970). "A catalogue of stellar rotational velocities". Contributi Osservatorio Astronomico di Padova in Asiago 239 (1). Bibcode 1970CoAsi.239....1B. 
  6. ^ Batten, A. H. (1967). "Sixth catalogue of the orbital elements of spectroscopic binary systems". Publications of the Dominion Astrophysical Observatory, Victoria 13: 154–155. Bibcode 1967PDAO...13..119B. 
  7. ^ Samus, N. N.; Durlevich, O. V.; et al. (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".
Stars of Crux
Bayer