Theta Circini
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Circinus |
| Right ascension | 14h 56m 43.98738s [1] |
| Declination | −62° 46 51.6579′ [1] |
| Spectral type | B4Vnpe [1] |
Theta Circini (t Cir), is a star located in the constellation Circinus. Theta Circini is also known as HR 5551, and HD 131492. The star is a spectroscopic binary. The system is located at Right Ascension 14h 56m 44s and Declination -62 deg 46 arcmin 51 arcsec.[1] The system has a combined apparent visual magnitude of +5.11,[1] and is located 255 parsecs (833 light years) from the Sun.
Theta Circini A and B are both B4V dwarf stars with effective temperatures of 15000 Kelvin. Each has an apparent visual magnitude +5.9, and an absolute magnitude of -1.96 and a mass of 3.2 solar masses. The components are separated by 0.1 arcsec.
The system is notable for having three peculiar characteristics: its spectra, brightness variations, and stellar pulsations. The star is classified as an H-Alpha variable for its spectral variations. It is classified (due to the orbital characteristics), as a Gamma Cassiopeia variable. Finally, it is considered to be a BE Lacertae variable star, exhibiting massive pulsations.
References
- http://www.alcyone.de/cgi-bin/search.pl?object=HR5551
- http://server3.wikisky.org/starview?object_type=1&object_id=2046
- http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HR+5551&submit=SIMBAD+search
- http://varsao.com.ar/Curva_theta_Cir.htm (light curve)
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