Beta Canis Majoris

Beta Canis Majoris

Location of Β CMa.
Observation data Epoch J2000      Equinox J2000
Constellation	Canis Major
Right ascension	06h 22m 42s
Declination	-17° 57′ 21.3″
Apparent magnitude (V)	1.98
Characteristics
Spectral type	B1 II-III
U−B color index	-0.98
B−V color index	-0.23
Variable type	Beta Cephei
Astrometry
Radial velocity (Rv)	34 km/s
Proper motion (μ)	RA: -3.45 mas/yr Dec.: -0.47 mas/yr
Parallax (π)	6.53 ± 0.66 mas
Distance	approx. 500 ly (approx. 150 pc)
Absolute magnitude (MV)	-3.95
Details
Mass	? M☉
Radius	12 R☉
Luminosity	19,000 L☉
Temperature	22,000 K
Metallicity	?
Rotation	36 km/s.
Age	unknown years
Other designations
Murzim, Mirzam, Mirza, 2 Canis Majoris, HR 2294, BD−17°1467, HD 44743, SAO 151428, FK5 243, HIP 30324, GC 8223, CCDM 06227-1757

Beta Canis Majoris (β CMa, β Canis Majoris) is a star in the constellation of Canis Major. It has the traditional name Murzim, Al-Murzim or Mirzam.

Murzim is a variable magnitude blue-white giant star. The brightness of Murzim varies between 1.95 and +2.00 in a six-hour period. It is a Beta Cephei variable star. It is currently in the final stages of using hydrogen gas for fuel and will eventually exhaust its supply and begin using helium for fuel instead.

Beta Canis Majoris is located near the far end of the Local Bubble, a cavity in the local interstellar medium through which the Sun is traveling.

The traditional non-religious name in Arabic is (مرزم) for 'The Herald', and probably refers to its position, heralding Sirius in the night sky (i.e., rising before it).

In Chinese, 軍市 (Jūn Shì), meaning Market for Soldiers, refers to an asterism consisting of β Canis Majoris, ν³ Canis Majoris, 15 Canis Majoris, π Canis Majoris, ο¹ Canis Majoris and ξ¹ Canis Majoris.^[1] Consequently, β Canis Majoris itself is known as 軍市一 (Jūn Shì yī, English: the First Star of Market for Soldiers.)^[2]. From this Chinese name, the name Kuen She arose.^[3]

Modern legacy

Murzim appears on the flag of Brazil, symbolising the state of Amapá.^[4]

Namesakes

USS Murzim (AK-95) was a United States Navy Crater class cargo ship named after the star.

References

1. ^ (Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
2. ^ (Chinese) 香港太空館 - 研究資源 - 亮星中英對照表, Hong Kong Space Museum. Accessed on line November 23, 2010.
3. ^ Richard Hinckley Allen: Star Names — Their Lore and Meaning: Canis Major
4. ^ "Astronomy of the Brazilian Flag". FOTW Flags Of The World website. http://www.fotw.net/flags/br_astro.html.