145 G. Canis Majoris (HD 56577) is a single[10] K giant or supergiant star in the southern constellation of Canis Major. This star is Gould's 145th of Canis Major in his Uranometria Argentina. [11] Kostjuk erroneously lists it as simply "145 CMa". SIMBAD follows this error in its object query result as "* 145 CMa – Star".[12]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Canis Major |
| Right ascension | 07h 16m 36.83456s[1] |
| Declination | −23° 18′ 56.1383″[1] |
| Apparent magnitude (V) | 4.79[2] |
| Characteristics | |
| Spectral type | K3Ib-[3] or K4III[4] |
| B−V color index | 1.710[2] |
| Astrometry | |
| Radial velocity (Rv) | +28.05±0.42[5] km/s |
| Proper motion (μ) | RA: −3.816[1] mas/yr Dec.: +3.896[1] mas/yr |
| Parallax (π) | 1.2155 ± 0.0998 mas[1] |
| Distance | 2,700 ± 200 ly (820 ± 70 pc) |
| Details | |
| If a giant star | |
| Mass | 1.90[2] M☉ |
| Radius | 156 ± 11[2][a] R☉ |
| Luminosity | 5,250[2] L☉ |
| Surface gravity (log g) | 0.70[2] cgs |
| Temperature | 3,937±141[2] K |
| Metallicity [Fe/H] | 0.03[2] dex |
| Age | 1.05[2] Gyr |
| If a supergiant | |
| Mass | 7.8±0.5[6] M☉ |
| Radius | 315[7] R☉ |
| Luminosity | 23,660[7] L☉ |
| Temperature | 3,986[7] K |
| Rotational velocity (v sin i) | 7.4±1.0[8] km/s |
| Age | 35.4±2.0[6] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
The properties and evolutionary state of 145 G. CMa are disputed, it being classed either as a young massive supergiant or a somewhat older and less massive giant. It has been given two MK spectral classifications: K3Ib[3] (corresponding to a supergiant) and K4III[4] (corresponding to a giant). Tezzlaff et al. gives a large mass of 7.8 M☉ and a young age of 35 million years,[6] while Earle Luck gives a smaller mass of 1.9 M☉ and a higher age of 1.05 billion years.[2] The effective temperature of the star is of 3,980 K,[7] which gives it a orange hue typical of K-type stars.[13]
Based on the assumption that it is a supergiant, 145 CMa has been given a large radius of 315 R☉ and a luminosity of 23,660 L☉.[7] Assuming it is a giant, Earle Luck give a much lower luminosity of 5,250 L☉ with a corresponding radius of 156 R☉.[a][2] By the distance implied by its Gaia DR2 parallax, it would have a luminosity of 14,000 L☉, rather high for a giant.[5] An older measurement based on the Hipparcos distance of 435 parsecs (1,420 ly) give a lower luminosity of 5,960 L☉.[14]
The star is one component of a close double, the other being HD 56578 which on its own would be a faint naked-eye star. The two are separated by 27″.[15] The two stars appear to be unrelated and the close alignment accidental, with HD 56578 being a much closer and less luminous Am star.[16]
Notes
edit- ^ a b Applying the Stefan–Boltzmann law with a nominal solar effective temperature of 5,772 K:
- .
References
edit- ^ a b c d e 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.
- ^ a b c d e f g h i j k Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal, 150 (3): 88, arXiv:1507.01466, Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88, S2CID 118505114.
- ^ a b Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.
- ^ a b Houk, Nancy; Smith-Moore, M. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1988mcts.book.....H.
- ^ 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 Tetzlaff, N.; et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society, 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x, S2CID 118629873.
- ^ a b c d e Healy, Sarah; Horiuchi, Shunsaku; Colomer Molla, Marta; Milisavljevic, Dan; Tseng, Jeff; Bergin, Faith; Weil, Kathryn; Tanaka, Masaomi; Otero, Sebastián (2024-04-01). "Red supergiant candidates for multimessenger monitoring of the next Galactic supernova". Monthly Notices of the Royal Astronomical Society. 529 (4): 3630–3650. arXiv:2307.08785. Bibcode:2024MNRAS.529.3630H. doi:10.1093/mnras/stae738. ISSN 0035-8711.
- ^ De Medeiros, J. R.; et al. (2002), "A catalog of rotational and radial velocities for evolved stars. II. Ib supergiant stars", Astronomy and Astrophysics, 395: 97–98, arXiv:1312.3474, Bibcode:2002A&A...395...97D, doi:10.1051/0004-6361:20021214.
- ^ "HD 56577". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-01-06.
- ^ 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, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- ^ Gould, B. A., (2009) Uranometria Argentina, (Reprinted and updated by Pilcher, F.)[1] Archived 2016-03-05 at the Wayback Machine
- ^ SIMBAD query * 145 CMa – Star
- ^ "The Colour of Stars". Australia National Telescope Facility. 6 March 2024. Retrieved 2024-05-27.
- ^ McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (2012-11-01). "Fundamental parameters and infrared excesses of Hipparcos stars". Monthly Notices of the Royal Astronomical Society. 427 (1): 343–357. arXiv:1208.2037. Bibcode:2012MNRAS.427..343M. doi:10.1111/j.1365-2966.2012.21873.x. ISSN 0035-8711. 145 CMa's database entry at VizieR.
- ^ Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001), "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog", The Astronomical Journal, 122 (6): 3466, Bibcode:2001AJ....122.3466M, doi:10.1086/323920.
- ^ 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.