Epoch J2000 Equinox J2000
|Right ascension||08h 09m 31.95013s|
|Declination||–47° 20′ 11.7108″|
|Apparent magnitude (V)||1.78/4.27|
|Spectral type||WC8 + O7.5e|
|U−B color index||–0.94|
|B−V color index||–0.25|
|Radial velocity (Rv)||+35 km/s|
|Proper motion (μ)||RA: –6.07 mas/yr
Dec.: +10.43 mas/yr
|Parallax (π)||2.92 ± 0.30 mas|
|Luminosity (bolometric)||150,000 L☉|
Gamma Velorum (γ Vel, γ Velorum) is a star system in the constellation Vela. At magnitude +1.7, it is one of the brightest stars in the night sky. It has the traditional names Suhail and Suhail al Muhlif, which confusingly also apply to Lambda Velorum. It also has a more modern popular name Regor, which was invented as a practical joke by the Apollo 1 astronaut Gus Grissom for his fellow astronaut Roger Chaffee. Due to the exotic nature of its spectrum (bright emission lines in lieu of dark absorption lines) it is also dubbed the "Spectral Gem of Southern Skies".
The Gamma Velorum system is composed of at least four stars. The brightest member, γ² Velorum or γ Velorum A, is actually a spectroscopic binary composed of a blue supergiant of spectral class O7.5 (~30 M☉), and a massive Wolf-Rayet star (~9 M☉, originally ~35 M☉). The binary has an orbital period of 78.5 days and separation of 1 AU. The Wolf-Rayet star is likely to end its life in a Type Ib supernova explosion; it is one of the nearest supernova candidates to the Sun. Its nearest companion, the bright (apparent magnitude +4.2) γ¹ Velorum or γ Velorum B, is a spectroscopic binary with a period of 1.48 days. Only the primary is detected and it is a blue-white B2III. It is separated from the Wolf-Rayet binary by 41.2", and the separation can easily be resolved with binoculars.
Gamma Velorum has several fainter companions that share a common motion and are likely to be members of the Vela OB2 association. The magnitude +7.3 CD-46 3848 is a white F0 star at is 62.3 arcseconds from the A component. At 93.5 arcseconds is another binary star, an F0 star of magnitude +9.2. γ Velorum is associated with several hundred pre main sequence stars within less than a degree.
The medieval name Suhail (Al Suhail, Alsuhail, Suhail al Muhlif, Muliphein) is short for the Arabic سهيل المحلف suhayl al-muħlif "The glorious (star) of the oath".
The Chinese name for the star is 天社一 (Mandarin: tiān shè yī), which means "The First Star of the Celestial Altar."
- Gamma Cassiopeiae, informally named Navi for astronaut Virgil Ivan "Gus" Grissom
- Iota Ursae Majoris, informally named Dnoces for astronaut Edward H. White II
- van Leeuwen, F. (November 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
- Johnson, H. L. et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory 4 (99), Bibcode:1966CoLPL...4...99J
- Wilson, Ralph Elmer (1953), General Catalogue of Stellar Radial Velocities, Washington: Carnegie Institution of Washington, Bibcode:1953QB901.W495.....
- Eldridge, J. J. (2009). "A new-age determination for γ2 Velorum from binary stellar evolution models". Monthly Notices of the Royal Astronomical Society: Letters 400: L20–L23. arXiv:0909.0504. Bibcode:2009MNRAS.400L..20E. doi:10.1111/j.1745-3933.2009.00753.x.
- Apollo 15 Lunar Surface Journal, Post-landing Activities, commentary at 105:11:33
- Hoffleit. "The Bright Star Catalogue, 5th Revised Ed.". Retrieved 2007-08-08.
- Beech, Martin (December 2011), "The past, present and future supernova threat to Earth's biosphere", Astrophysics and Space Science 336 (2): 287–302, Bibcode:2011Ap&SS.336..287B, doi:10.1007/s10509-011-0873-9
- Jeffries, R. D.; Naylor, T.; Walter, F. M.; Pozzo, M. P.; Devey, C. R. (2009). "The stellar association around Gamma Velorum and its relationship with Vela OB2". Monthly Notices of the Royal Astronomical Society 393 (2): 538. doi:10.1111/j.1365-2966.2008.14162.x.