Merak (star)

Database links to β Ursae Maioris

Star Merak (β Ursae Maioris)
β UMa in the constellation "Great Bear"
AladinLite
Observation dates equinox :  J2000.0 , epoch : J2000.0
Constellation	Big Bear
Right ascension	11 h 1 m 50.48 s
declination	+ 56 ° 22 ′ 56.7 ″
Apparent brightness	2.35 likes
Typing
B − V color index	−0.02
U − B color index	0.00
R − I index	−0.04
Spectral class	A1 IV
Astrometry
Radial velocity	(−13.1 ± 0.1) km / s
parallax	(40.90 ± 0.16)  mas
distance	(79.7 ± 0.3)  ly (24.4 ± 0.1)  pc
Visual absolute brightness M vis	0.49 mag
Proper movement
Rec. Share:	(81.43 ± 0.10)  mas / a
Dec. portion:	(33.49 ± 0.09)  mas / a
Physical Properties
Dimensions	2.6  M ☉
radius	3.1  R ☉
Luminosity	73  L ☉
Effective temperature	9500  K
Metallicity [Fe / H]	−0.03
Other names and catalog entries
Bayer name β Ursae Maioris Flamsteed name 48 Ursae Maioris Bonn survey BD + 57 ° 1302 Bright Star Catalog HR 4295 [1] Henry Draper Catalog HD 95418 [2] Gliese catalog FY 9343 [3] Hipparcos catalog HIP 53910 [4] SAO catalog SAO 27876 [5] Tycho catalog TYC 3827-1079-1 [6] 2MASS catalog 2MASS 11015046 + 5622566 [7] Other names FK5 416

Merak (from Arabic مراقّ البطن, DMG marāqq al-baṭn  'soft parts of the abdomen' ^a ) is the proper name of the star Beta Ursae Maioris (β UMa) in the constellation Great Bear . Together with Dubhe (α UMa) it forms the rear end of the body of the Big Dipper , the extension of which points beyond Dubhe to the North Star . Merak has an apparent magnitude of 2.3 mag and is about 80 light years away.

properties

Merak is a white subgiant about 2.6 times the mass, 3 times the diameter and over 70 times the luminosity of the sun . Its surface temperature is around 9500 K. The star is slightly variable, it shows fluctuations in brightness of 0.05 mag and a projected equatorial rotation speed v ∙ sin i of around 30 km / s was measured for it.

With four other of the seven bright chariot stars, Merak belongs to the so-called group of bears , a moving cluster of over a hundred stars spread across half the sky. Our sun is in the range of this group, but moves in a different direction. Seen from Earth, there are two Messier objects - M 97, the Owl Nebula and M 108 , a spiral galaxy - in the immediate vicinity of the star. Both are too faint at about 10 mag to be seen with the naked eye.

designation

According to the “IAU Catalog of Star Names” of the Working Group on Star Names (WGSN) of the IAU for the standardization of star names, the name “Merak” was officially assigned to the star β Ursae Majoris in 2016.

^aNote the importance of "Merak": In many English-speaking websites, the term loins , thus "loins", stated. By definition, the loin is the deepened area between the lumbar spine, the lower ribs and the hips. But as above is marāqq used in Arabic in conjunction with the word for belly and the correct meaning The soft parts of the belly can be found in the first Persian-Arabic-English dictionary of John Richardson . In order to take the focus off the back (or even the figurative meaning “genitals”), as well as with regard to the anatomical position of the star Merak, if one superimposes the traditional pictorial representation of the constellation, instead of using the term “loin” The term “flank” is most likely to offer as an interpretation in Ursa maior. The proper name of the star Marakk in the constellation Capricorn is derived from the same Arabic term , which should not be confused with Merak because of this similarity of the name.

Trivia

Merak is the namesake of the Maserati Merak sports car .

See also

• List of the brightest stars

Web links

• http://stars.astro.illinois.edu/Sow/merak.html

Individual evidence

1. ^ ^{A b c d} VizieR: Hipparcos, the New Reduction (van Leeuwen, 2007) - The Astrometric Catalog
2. ↑ ^{a b c} VizieR: Stellar Photometry in Johnson's 11-color system (Ducati, 2002)
3. ↑ ^{a b} VizieR: Extended Hipparcos Compilation (XHIP) (Anderson +, 2012)
4. ↑ VizieR: Pulkovo radial velocities for 35493 HIP stars (Gontcharov, 2006)
5. ↑ VizieR: Stars within 25 pc of the Sun (Woolley + 1970)
6. ↑ ^{a b c} VizieR: Rotational velocities of A-type stars. IV. (Zorec +, 2012)
7. ^ VizieR: Fundamental parameters of stars (Allende Prieto +, 1999)
8. ^ VizieR: Linear polarization of nearby bright stars (Bailey +, 2010)
9. ↑ Bulletin of the IAU Working Group on Star Names, No. 2. IAU Division C Education, Outreach and Heritage, 2016 ( PDF; 158 kB ).
10. ↑ تعريف و معنى مراقّ في معجم المعاني الجامع - معجم عربي عربي (see entry 3.). Almaany.com, accessed January 18, 2017 (Arabic). 
11. ↑ J. Richardson, Ch. Wilkins, F. Johnson: A Dictionary, Persian, Arabic, and English; with a Dissertation on the Languages, Literature, and Manners of Eastern Nations. London 1829, p. 1384.