Theta Normae
  | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Norma |
| Right ascension | 16h 15m 15.31776s |
| Declination | −47° 22′ 19.2716″ |
| Apparent magnitude (V) | 5.13 |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | B8 V |
| B−V color index | −0.12 |
| Astrometry | |
| Radial velocity (Rv) | +1.4±4.2 km/s |
| Proper motion (μ) | RA: −34.654 mas/yr Dec.: −45.784 mas/yr |
| Parallax (π) | 8.9049±0.1072 mas |
| Distance | 366 ± 4 ly (112 ± 1 pc) |
| Absolute magnitude (MV) | −0.23 |
| Details | |
| Mass | 3.6 M☉ |
| Radius | 3.05 R☉ |
| Luminosity | 184 L☉ |
| Surface gravity (log g) | 4.5 cgs |
| Temperature | 12,341 K |
| Rotation | 1.144 days |
| Rotational velocity (v sin i) | 109 km/s |
| Age | 17 Myr |
| Other designations | |
| θ Nor, CD−47°10611, HD 145842, HIP 79653, HR 6045, SAO 226600 | |
| 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 and is visible to the naked eye as a faint, blue-white-hued point of light. Based upon an annual parallax shift of 8.9 mas as seen from Earth, this system is located about 366 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.
Chini et al. (2012) identified this as a single-lined spectroscopic binary system. The visible component is a B-type main-sequence star with a stellar classification of B8 V. It is about 17 million tears old, with 3.6 times the mass of the Sun and 3.05 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. It is a mercury-manganese star, a B to A-type star with overabundances of the chemical elements mercury and manganese. It takes 1.144 days to fully rotate and has a projected rotational velocity of 109 km/s, unusually fast of a HgMn star.
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.
References
- 1 2 3 4 5 6 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- 1 2 3 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.
- 1 2 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, S2CID 59451347, A61.
- ↑ 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.
- 1 2 3 4 5 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, doi:10.3847/0004-6256/152/2/40, S2CID 119179065.
- 1 2 3 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, S2CID 118438871, 15.
- 1 2 3 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, S2CID 118665352.
- 1 2 3 Monier, Richard (2025-07-09), "The Far Ultraviolet Spectrum of the Newly Discovered HgMn Star HD 145842 (θ Nor)", Research Notes of the AAS, 9 (7): 167, doi:10.3847/2515-5172/adec7c, ISSN 2515-5172.
- ↑ "tet Nor". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-08-12.
{{cite web}}: CS1 maint: postscript (link) - ↑ 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, S2CID 18759600.
- ↑ 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, S2CID 119108982.
- ↑ 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, S2CID 119120749.
