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FN Canis Majoris

A light curve for FN Canis Majoris from Hipparcos data. Adapted from Rivinius et al. (2011)
Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Canis Major
Right ascension	07 06 40.76672
Declination	−11° 17′ 38.4396″
Apparent magnitude (V)	5.41 (5.69 + 7.04)
Characteristics
Spectral type	B0 III/IV or B2 Ia/ab
B−V color index	0.033±0.004
Astrometry
Radial velocity (Rv)	+31.0±4.2 km/s
Proper motion (μ)	RA: −3.14±0.72 mas/yr Dec.: +3.32±0.55 mas/yr
Parallax (π)	1.07 ± 0.61 mas
Distance	approx. 3,000 ly (approx. 900 pc)
Details
Mass	19.23±1.85, 24.0±0.1, 35.5±4.6 M☉
Luminosity (bolometric)	122,079, 690,000 L☉
Surface gravity (log g)	3.59±0.11 cgs
Temperature	26,850, 33,600±1,840 K
Rotational velocity (v sin i)	100±9 km/s
Age	6.0±0.1 Myr
Other designations
FN CMa, BD−11°1790, GC 9389, HD 53974, HIP 34301, HR 2678, SAO 152394, WDS J07067-1118
Database references
SIMBAD	data

FN Canis Majoris is a binary star system in the southern constellation Canis Major, near the northern constellation border with Monoceros. It is dimly visible to the naked eye with a combined apparent visual magnitude of 5.41. The system is located at a distance of approximately 3,000 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +31 km/s. It is a runaway star associated with the Sh 2-296 nebula in the CMa OB1 association, and has a conspicuous bow-shock feature.

The brighter component is a visual magnitude 5.69 B-type star that has been assigned various stellar classification from B0 III/IV to B2 Ia/ab, suggesting it is an evolved state. In 1967, Graham Hill announced his discovery that the star, then known as HD 53974, is a variable star. It was given its variable star designation, FN Canis Majoris, in 1970. In the past it was classified as a Beta Cephei type variable star with an apparent magnitude that was measured varying between +5.38 and +5.42 over a period of 36.7 hours, but is no longer considered to be one. This is a massive star with estimates ranging from 19 to 36 times the mass of the Sun, and luminosity estimates of 122,079 to 690,000 times the Sun's luminosity. The magnitude 7.04 companion is located at an angular separation of 0.60″ from the primary at a position angle of 111°, as of 2003.

References

1. Rivinius, Th.; Stahl, O.; Štefl, S.; Baade, D.; Townsend, R. H. D.; Barrera, L. (July 2011). "The (B0+?)+O6 system FN CMa: a case for tidal-pulsational interaction?". Proceedings IAU Symposium. 272: 543–544. arXiv:1009.3512. Bibcode:2011IAUS..272..543R. doi:10.1017/S1743921311011380.
2. ^ 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.
3. ^ 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.
4. ^ Eggleton, P. P.; Tokovinin, A. A. (2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.
5. ^ Tjin A Djie, H. R. E.; et al. (August 2001). "The stellar composition of the star formation region CMa R1 - II. Spectroscopic and photometric observations of nine young stars". Monthly Notices of the Royal Astronomical Society. 325 (4): 1441–1457. arXiv:astro-ph/0103349. Bibcode:2001MNRAS.325.1441T. doi:10.1046/j.1365-8711.2001.04541.x. S2CID 117112792.
6. ^ Fernandes, B.; et al. (August 2019). "Runaways and shells around the CMa OB1 association". Astronomy & Astrophysics. 628: 15. arXiv:1906.00113. Bibcode:2019A&A...628A..44F. doi:10.1051/0004-6361/201935484. S2CID 173990935. A44.
7. ^ Hohle, M. M.; et al. (2010). "Masses and luminosities of O- and B-type stars and red supergiants". Astronomische Nachrichten. 331 (4): 349–360. arXiv:1003.2335. Bibcode:2010AN....331..349H. doi:10.1002/asna.200911355. S2CID 111387483.
8. ^ 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
9. ^ Zorec, J.; et al. (November 2016). "Critical study of the distribution of rotational velocities of Be stars. I. Deconvolution methods, effects due to gravity darkening, macroturbulence, and binarity". Astronomy & Astrophysics. 595: 26. Bibcode:2016A&A...595A.132Z. doi:10.1051/0004-6361/201628760. hdl:11336/37946.
10. "FN CMa". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-03-09.
11. ^ Hill, Graham (August 1967). "On Beta Cephei Stars: a Search for Beta Cephei Stars". Astrophysical Journal Supplement. 14: 263–300. Bibcode:1967ApJS...14..263H. doi:10.1086/190156. ISSN 0067-0049. Retrieved 1 January 2025.
12. Kukarkin, B. V.; Kholopov, P. N.; Perova, N. B. (October 1970). "57th Name-List of Variable Stars" (PDF). Information Bulletin on Variable Stars. 480: 1–39. Bibcode:1970IBVS..480....1K. Retrieved 1 January 2025.
13. Lefèvre, L.; Marchenko, S. V.; Moffat, A. F. J.; Acker, A. (2009). "A systematic study of variability among OB-stars based on HIPPARCOS photometry" (PDF). Astronomy and Astrophysics. 507 (2): 1141–1201. Bibcode:2009A&A...507.1141L. doi:10.1051/0004-6361/200912304. ISSN 0004-6361.
14. Stankov, Anamarija; Handler, Gerald (2005). "Catalog of Galactic β Cephei Stars". The Astrophysical Journal Supplement Series. 158 (2): 193–216. arXiv:astro-ph/0506495. Bibcode:2005ApJS..158..193S. doi:10.1086/429408. ISSN 0067-0049. S2CID 119526948.
15. Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920.

v t e Constellation of Canis Major
Canis Major in Chinese astronomy List of stars in Canis Major
Stars	Bayer α (Sirius) β (Mirzam) γ (Muliphein) δ (Wezen) ε (Adhara) ζ (Furud) η (Aludra) θ ι κ λ μ ν ν ν ξ ξ ο ο π σ (Unurgunite) τ ω Flamsteed 10 11 12 15 17 26 27 29 Variable R W Z UW VY CX EZ FN FS FY LS NR V352 HR 2225 2318 2437 2447 2450 2758 2764 2766 2812 HD 43162 43197 (Amadioha) 45184 45364 47186 54879 Other RX J0720.4−3125 WASP-64 (Atakoraka) WISE 0713−2917 WR 7
Exoplanets ν Canis Majoris b HD 47536 b c HD 47186 b c HD 45364 b c HD 43197 b
Star clusters	NGC NGC 2204 NGC 2354 NGC 2360 NGC 2362 NGC 2374 Other Gaia 1 Messier 41
Nebulae NGC 2359 NGC 2361 Sh2-297
Galaxies	NGC 2207 2217 2227 2280 2283 2293 Other Canis Major Overdensity IC 2163
Astronomical events SN 1999ec SN 2003H
Category

• B-type giants
• Canis Major
• Objects with variable star designations
• Bright Star Catalogue objects
• Henry Draper Catalogue objects
• Hipparcos objects
• Durchmusterung objects
• Binary stars