Beta Canis Majoris

From Wikipedia, the free encyclopedia
(Redirected from Murzim)
Jump to navigation Jump to search

Template:Short description

Beta Canis Majoris
Observation data
Epoch J2000      Equinox J2000
Constellation Canis Major
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) 1.985[2] (1.97 - 2.01[3])
Characteristics
Spectral type B1 II-III[4]
U−B Template:Engvar −0.99[2]
B−V Template:Engvar −0.235[2]
Variable type β Cep[5]
Astrometry
Radial velocity (Rv)+33.7[6] km/s
Proper motion (μ) RA: −3.23[1] mas/yr
Dec.: −0.78[1] mas/yr
Parallax (π)6.62±0.22 mas[1]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)−4.1[7]
Details
Mass12 or 12.6[8] Template:Solar mass
Radius7.4 or 8.2[8] Template:Solar radius
LuminosityTemplate:Val[9] Template:Solar luminosity
Surface gravity (log g)Template:Val[8] cgs
TemperatureTemplate:Val[9] K
Metallicity [Fe/H]0.04 ± 0.10[10] dex
RotationTemplate:Val[8] days
Rotational velocity (v sin i)31 ± 5[10] km/s
Age12.2 or 13.8[8] Myr
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
Mirzam, Murzim, Mirza,[11] 2 Canis Majoris, HR 2294, BD−17°1467, HD 44743, SAO 151428, FK5 243, HIP 30324, GC 8223, CCDM 06227-1757[12]
Database references
SIMBADdata

Script error: No such module "Check for unknown parameters".

Beta Canis Majoris (β Canis Majoris, abbreviated Beta CMa, β CMa), also named Mirzam Template:IPAc-en,[13] is a star in the southern constellation of Canis Major, the "Great Dog", located at a distance of about 500 light-years (150 parsecs) from the Sun.[1] In the modern constellation it lies at the position of the dog's front leg.

Nomenclature

Beta Canis Majoris is the star's Bayer designation. The traditional names Mirzam, Al-Murzim or Murzim,[11] derive from the Arabic (مرزم) for 'The Herald', and probably refer to its position, heralding (i.e., rising before) Sirius in the night sky. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[14] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[15] included a table of the first two batches of names approved by the WGSN; which included Mirzam for this star.

In Chinese, Script error: No such module "Lang". (Script error: No such module "Lang".), meaning 'Market for Soldiers', refers to an asterism consisting of β Canis Majoris, Nu3 Canis Majoris, 15 Canis Majoris, Pi Canis Majoris, Omicron1 Canis Majoris and Xi1 Canis Majoris.[16] Consequently, β Canis Majoris itself is known as Script error: No such module "Lang". (Script error: No such module "Lang"., Template:Langx).[17] From this Chinese name arose the name Kuen She.[11]

The Dunhuang Star Chart noted β Canis Majoris as Yeji "Pheasant Cock", though was located about 10 degrees too far north of its correct position.[18]

Beta Canis Majoris was called Oupo by the people of the Tuamotus.Template:Sfn

Properties

Pulsation cycles[10]
Frequency
(day−1) 		Amplitude
(km s−1)
3.9793 2.7
3.9995 2.6
4.1832 0.7

Mirzam is a Beta Cephei variable that varies in apparent magnitude between +1.97 and +2.01 over a six-hour period, a change in brightness that is too small to be discerned with the naked eye. It exhibits this variation in luminosity because of periodic pulsations in its outer envelope, which follow a complex pattern with three different cycles; all about six hours in length. The two dominant pulsation frequencies have a combined beat period of roughly 50 days. The strongest pulsation mode is a radial first overtone, while the second is non-radial.[10]

File:BetaCMaLightCurve.png
A light curve for Beta Canis Majoris, plotted from Hipparcos data[19]

This star has a mass of about 12–13 times the mass of the Sun with 7.4 or 8.2 times the Sun's radius.[8] The effective temperature of the star's outer envelope is about 24,700 K,[9] which is much higher than the Sun's at 5,778 K. The energy emitted at the high temperature of the former is what gives this star a blue-white hue characteristic of a B-type star.[20] The estimated age of Mirzam is 12–14 million years,[8] which is long enough for a star of this mass to have evolved into a giant star. The stellar classification of B1 II-III[4] indicates that the spectrum matches a star part way between a giant star and a bright giant. This star has a rotation period of 13.6 days and is inclined 57.6 ° as seen from Earth.[8]

Beta Canis Majoris is located near the far end of the Local Bubble,[21] a cavity in the local interstellar medium through which the Sun is traveling. It is located within the Mirzam Tunnel, a region of less dense concentration between the stars and HII regions surrounding the Ori OB1 and Vel OB2 associations. Beta Canis Majoris was the brightest star in the night sky around four million years ago, peaking with an apparent magnitude of -3.65, or more than seven times as bright as Sirius today.[22]

In culture

Mirzam appears on the flag of Brazil, symbolising the state of Amapá.[23]

Murzim (AK-95) was a United States Navy Crater class cargo ship named after one of the star's alternative traditional names.

References

Template:Reflist

Sources

  • Script error: No such module "citation/CS1".

Template:Stars of Canis Major

Template:Authority control

  1. ↑ a b c d e f Cite error: Invalid <ref> tag; no text was provided for refs named aaa474_2_653
  2. ↑ a b c Cite error: Invalid <ref> tag; no text was provided for refs named mnassa31_69
  3. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named IBVS
  4. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named apj573_1_359
  5. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named gcvs
  6. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named gcsrv53
  7. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named MNRAS369
  8. ↑ a b c d e f g h Cite error: Invalid <ref> tag; no text was provided for refs named fossati
  9. ↑ a b c Cite error: Invalid <ref> tag; no text was provided for refs named schultz2019
  10. ↑ a b c d Cite error: Invalid <ref> tag; no text was provided for refs named aaa459_2_589
  11. ↑ a b c Cite error: Invalid <ref> tag; no text was provided for refs named allen1899
  12. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named SIMBAD
  13. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named IAU-CSN
  14. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named WGSN
  15. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named WGSN1
  16. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named zh
  17. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named lcsd
  18. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named ChineseSky
  19. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named HIPCurve
  20. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named csiro
  21. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Welsh
  22. ↑ Script error: No such module "Citation/CS1". – based on computations from HIPPARCOS data. (The calculations exclude stars whose distance or proper motion is uncertain.)
  23. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named flag
Retrieved from "http://debianws.lexgopc.com/wiki143/index.php?title=Beta_Canis_Majoris&oldid=2045217"