Astronomy:Theta Canis Majoris
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Canis Major |
| Right ascension | 06h 54m 11.399s[1] |
| Declination | −12° 02′ 19.06″[1] |
| Apparent magnitude (V) | 4.08[2] |
| Characteristics | |
| Evolutionary stage | Red giant branch[3] |
| Spectral type | K4 III[2] |
| U−B color index | +1.69[4] |
| B−V color index | +1.43[4] |
| Astrometry | |
| Radial velocity (Rv) | +96.2±0.1[5] km/s |
| Proper motion (μ) | RA: −136.454[1] mas/yr Dec.: −14.322[1] mas/yr |
| Parallax (π) | 12.0676 ± 0.62[1] mas |
| Distance | 270 ± 10 ly (83 ± 4 pc) |
| Absolute magnitude (MV) | −0.36±0.15[6] |
| Details[5] | |
| Mass | 0.95±0.03 M☉ |
| Radius | 33.01±0.75[7] R☉ |
| Luminosity | 304.9±7[7] L☉ |
| Surface gravity (log g) | 1.67±0.08 cgs |
| Temperature | 4,196±43[7] K |
| Metallicity [Fe/H] | −0.52±0.04 dex |
| Rotational velocity (v sin i) | 2.72±0.40 km/s |
| Age | 10.41±1.31 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Theta Canis Majoris is a solitary,[9] orange-hued star near the northern edge[10] of the constellation Canis Major, forming the nose of the "dog".[11] Its name is a Bayer designation that is Latinized from θ Canis Majoris, and abbreviated Theta CMa or θ CMa. The star is visible to the naked eye with an apparent visual magnitude of 4.08.[2] Based upon an annual parallax shift of 12.07 mas as seen from Earth,[1] it is located about 270 light years distant. The star is moving away from the Sun with a radial velocity of +96.2 km/s.[5]
This is a evolved K-type giant star with a stellar classification of K4 III,[2] having exhausted the supply of hydrogen at its core then expanded. Theta Canis Majoris is 5% less massive than the Sun,[5] but has grown to 33 times the Sun's girth.[7] This star is around ten billion years old,[5] over twice the age of the Solar System.[12] It radiates 305 times the Sun's luminosity from its expanded photosphere at an effective temperature of 4,200 K.[7] This temperature gives it the cool orange hue of a K-type star.[13]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 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.
- ↑ 2.0 2.1 2.2 2.3 Setiawan, J. et al. (July 2004), "Precise radial velocity measurements of G and K giants. Multiple systems and variability trend along the Red Giant Branch", Astronomy and Astrophysics 421: 241–254, doi:10.1051/0004-6361:20041042-1, Bibcode: 2004A&A...421..241S.
- ↑ Reffert, Sabine et al. (2015), "Precise radial velocities of giant stars. VII. Occurrence rate of giant extrasolar planets as a function of mass and metallicity", Astronomy and Astrophysics 574: A116, doi:10.1051/0004-6361/201322360, Bibcode: 2015A&A...574A.116R.
- ↑ 4.0 4.1 Johnson, H. L. et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory 4 (99): 99, Bibcode: 1966CoLPL...4...99J.
- ↑ 5.0 5.1 5.2 5.3 5.4 Jofré, E. et al. (2015), "Stellar parameters and chemical abundances of 223 evolved stars with and without planets", Astronomy & Astrophysics 574: A50, doi:10.1051/0004-6361/201424474, Bibcode: 2015A&A...574A..50J. Theta Canis Majoris' database entry at VizieR.
- ↑ da Silva, L. et al. (November 2006), "Basic physical parameters of a selected sample of evolved stars", Astronomy and Astrophysics 458 (2): 609–623, doi:10.1051/0004-6361:20065105, Bibcode: 2006A&A...458..609D.
- ↑ 7.0 7.1 7.2 7.3 7.4 Baines, Ellyn K. et al. (December 2023), "33 New Stellar Angular Diameters from the NPOI, and Nearly 180 NPOI Diameters as an Ensemble", The Astronomical Journal 166 (6): 268, doi:10.3847/1538-3881/ad08be, ISSN 0004-6256, Bibcode: 2023AJ....166..268B.
- ↑ "tet CMa". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=tet+CMa.
- ↑ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869–879, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ Kaler, James N. (March 8, 2013), "Theta and Lambda Canis Majoris", STARS (University of Illinois), http://stars.astro.illinois.edu/sow/thetacma.html, retrieved 2017-09-08.
- ↑ Crossen, Craig; Rhemann, Gerald (2012), Sky Vistas: Astronomy for Binoculars and Richest-Field Telescopes, Springer Science & Business Media, p. 112, ISBN 978-3709106266, https://books.google.com/books?id=3vELBwAAQBAJ&pg=PA112.
- ↑ (in en) How old is the Solar System? Astronomers calculate its age by studying rocks that fall from space, 10 April 2024, https://www.skyatnightmagazine.com/space-science/how-old-solar-system, retrieved 2024-09-26.
- ↑ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html, retrieved 2012-01-16.
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