Omicron1 Canis Majoris
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Canis Major |
Right ascension | 06h 54m 07.95237s[1] |
Declination | −24° 11′ 03.1597″[1] |
Apparent magnitude (V) | 3.87[2] (3.78 - 3.99[3]) |
Characteristics | |
Spectral type | K2.5 Iab[4] |
U−B color index | +1.99[2] |
B−V color index | +1.73[2] |
Variable type | Lc[3] |
Absolute magnitude (MV) | −4.69[4] |
Details | |
Myr | |
SAO 172542, GC 9059 | |
Database references | |
SIMBAD | data |
Omicron1 Canis Majoris (ο1 CMa, ο1 Canis Majoris) is a red supergiant star in the constellation Canis Major. It is also a variable star.
Name
Distance
The distance to ο1 Canis Majoris is uncertain. It is strongly associated with the Collinder 121 stellar association, located around 3,500 light years (1,085 parsecs) distant.[15] Its original Hipparcos parallax placed it at 610 pc, similar to the distance of EZ Canis Majoris, another member of Cr 121. ο1 CMa appears to be interacting with the nebula around EZ CMa, implying the two are at the same distance. However, the revised Hipparcos parallax is only 0.22 mas, with a margin of error of 0.43 mas, so the distance is not well-defined but likely to be large. The distance to EZ CMa is now thought to be around 1,500 pc. Conversely, though only separated by 2 degrees from the blue supergiant ο2 Canis Majoris, the two appear to be unrelated.[10]
Description
The star itself is an orange K-type supergiant of spectral type K2.5 Iab and is an irregular variable star, varying between apparent magnitudes 3.78 and 3.99. A cool star, its surface temperature is around 3,900 K.[4] Around 8 times as massive as the Sun with around 280 times its diameter, it shines with 16,000 times its luminosity. Interstellar dust only obscures it slightly, and its apparent magnitude is 0.16 fainter than it would be if unobscured.[4] Thought to be around 18 million years old, ο1 Canis Majoris is undergoing nuclear fusion of helium in its core to generate energy and will one day explode as a type II supernova.[10]
References
- ^ S2CID 148571616.
- ^ Bibcode:2002yCat.2237....0D.
- ^ Bibcode:2009yCat....102025S.
- ^ S2CID 15109583.
- Bibcode:1967IAUS...30...57E.
- ^ .
- S2CID 59334290.
- .
- S2CID 10436552.
- ^ a b c Kaler, James B. "Omicron1 Canis Majoris". Stars. University of Illinois. Retrieved 24 February 2014.
- ^ John Flamsteed; Claudius Ptolemaeus; Tycho Brahe; Johannes Hevelius; Abraham Sharp (1725). Historia Coelestis Britannica: Complectens Praefationem spatiosam (sive in Stellarum Fixarum Catalogum Prolegomena) quae brevem Astronomiae Historiam praebet, atque Descriptionem Observationum peractarum, & Organorum adhibitorum tum a pristinis Astronomis, tum In Observatorio Regio Grenovicensi; Deinceps Fixarum Catalogum a Ptolemaeo, Uleg Beig, Tychone Brahaeo, Gulielmo Hessiae Landtgravio, ac Hevelio constructum ...: Quibus adnexus est Fixarum quarundam Australium Catalogus, in nostro Hemisphaerio non adspectabilium, Denique Tabulae …. Meere. pp. 2–.
- .
- ISBN 978-0-939923-78-6.
- ^ Wagman, p. 504.
- .
- ^ "Hipparcos Tools Interactive Data Access". Hipparcos. ESA. Retrieved 8 December 2021.