Theta Normae
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Norma |
| Right ascension | 16h 15m 15.31794s[1] |
| Declination | −47° 22′ 19.2710″[1] |
| Apparent magnitude (V) | 5.13[2] |
| Characteristics | |
| Spectral type | B8 V[3] |
| B−V color index | −0.12[2] |
| Astrometry | |
| Radial velocity (Rv) | +1.4±4.2[4] km/s |
| Proper motion (μ) | RA: −34.771 mas/yr Dec.: −45.813 mas/yr |
| Parallax (π) | 9.2718 ± 0.1692 mas[5] |
| Distance | 352 ± 6 ly (108 ± 2 pc) |
| Absolute magnitude (MV) | −0.23[6] |
| Details | |
| Mass | 3.6[7] M☉ |
| Radius | 3.05[8] R☉ |
| Luminosity | 184[9] L☉ |
| Surface gravity (log g) | 4.5[7] cgs |
| Temperature | 12,341[9] K |
| Rotational velocity (v sin i) | 251[10] km/s |
| Age | 17[7] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
θ Normae, Latinised as Theta Normae, is a binary star system in the constellation Norma. It has an apparent visual magnitude of 5.13[2] and is visible to the naked eye as a faint, blue-white hued point of light. Based upon an annual parallax shift of 9.27 mas as seen from Earth,[5] this system is located about 352 light years from the Sun. At that distance, the visual magnitude of these stars is diminished by an extinction of 0.45 due to interstellar dust.[12]
Chini et al. (2012) identified this as a single-lined spectroscopic binary system.[13] The visible component is a B-type main-sequence star with a stellar classification of B8 V.[3] It is about 17[7] million tears old and is spinning rapidly with a projected rotational velocity of 251 km/s.[10] The star has 3.6[7] times the mass of the Sun and 3.05[8] times the Sun's radius. It is radiating about 184 times the Sun's luminosity from its photosphere at an effective temperature of 12,341 K.[9] This system displays an infrared excess, suggesting a debris disk is orbiting at a mean radius of 21.8 AU with a temperature of 220 K.[8]
References
- ^ a b 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 Corben, P. M.; Stoy, R. H. (1968), "Photoelectric Magnitudes and Colours for Bright Southern Stars", Monthly Notes of the Astronomical Society of Southern Africa, 27: 11, Bibcode:1968MNSSA..27...11C.
- ^ a b Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 2, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.
- ^ de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, A61.
- ^ a b van Leeuwen, F. (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.
- ^ 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.
- ^ a b c d e Gullikson, Kevin; et al. (2016), "The Close Companion Mass-ratio Distribution of Intermediate-mass Stars", The Astronomical Journal, 152 (2): 40, arXiv:1604.06456, Bibcode:2016AJ....152...40G.
- ^ a b c Cotten, Tara H.; Song, Inseok (July 2016), "A Comprehensive Census of Nearby Infrared Excess Stars", The Astrophysical Journal Supplement Series, 225 (1): 24, arXiv:1606.01134, Bibcode:2016ApJS..225...15C, doi:10.3847/0067-0049/225/1/15, 15.
{{citation}}: CS1 maint: unflagged free DOI (link) - ^ a b c McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x.
{{citation}}: CS1 maint: unflagged free DOI (link) - ^ a b Uesugi, Akira; Fukuda, Ichiro (1970), "Catalogue of rotational velocities of the stars", Contributions from the Institute of Astrophysics and Kwasan Observatory, University of Kyoto, Bibcode:1970crvs.book.....U.
- ^ "tet Nor". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-08-12.
{{cite web}}: CS1 maint: postscript (link) - ^ Gontcharov, G. A. (November 2012), "Spatial distribution and kinematics of OB stars", Astronomy Letters, 38 (11): 694–706, arXiv:1606.09028, Bibcode:2012AstL...38..694G, doi:10.1134/S1063773712110035.
- ^ Chini, R.; et al. (2012), "A spectroscopic survey on the multiplicity of high-mass stars", Monthly Notices of the Royal Astronomical Society, 424 (3): 1925–1929, arXiv:1205.5238, Bibcode:2012MNRAS.424.1925C, doi:10.1111/j.1365-2966.2012.21317.x.
{{citation}}: CS1 maint: unflagged free DOI (link)
