Menkar
Star Menkar (α Ceti) |
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AladinLite | |||||||||||||||||||||
Observation dates equinox : J2000.0 , epoch : J2000.0 |
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Constellation | whale | ||||||||||||||||||||
Right ascension | 03 h 02 m 16.77 s | ||||||||||||||||||||
declination | + 04 ° 05 ′ 23.1 ″ | ||||||||||||||||||||
Apparent brightness | 2.53 (2.45 to 2.54) mag | ||||||||||||||||||||
Typing | |||||||||||||||||||||
B − V color index | +1.64 | ||||||||||||||||||||
U − B color index | +1.93 | ||||||||||||||||||||
R − I index | +1.16 | ||||||||||||||||||||
Spectral class | M1.5 IIIa | ||||||||||||||||||||
Astrometry | |||||||||||||||||||||
Radial velocity | -26.08 ± 0.02 km / s | ||||||||||||||||||||
parallax | 13.09 ± 0.44 mas | ||||||||||||||||||||
distance | 249 ± 8 ly 76 ± 3 pc |
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Visual absolute brightness M vis | -3.2 ± 0.3 mag | ||||||||||||||||||||
Proper movement | |||||||||||||||||||||
Rec. Share: | −10.41 ± 0.51 mas / a | ||||||||||||||||||||
Dec. portion: | −76.85 ± 0.36 mas / a | ||||||||||||||||||||
Physical Properties | |||||||||||||||||||||
Dimensions | 2.3 ± 0.2 M ☉ | ||||||||||||||||||||
radius | 89 ± 5 R ☉ | ||||||||||||||||||||
Luminosity |
1455 ± 328 L ☉ |
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Effective temperature | 3,795 ± 70 K | ||||||||||||||||||||
Metallicity [Fe / H] | 0.00 ± 0.30 | ||||||||||||||||||||
Other names and catalog entries |
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Menkar ( Arabic منخر الحوت, DMG Manḫar al-Ḥūt , nostril of the whale ') is the name of the star α Ceti (Alpha Ceti ). Menkar is a red giant of the spectral type M1.5IIIa about 250 light years away with about twice the solar mass and almost 90 times the solar radius. The correspondingly large area of Menkar's photosphere ensures, despite its very low surface temperature of around 3800 K, a luminosity that is around 1500 times greater than that of the smaller but hotter sun. Like many red giants , the star is variable , it probably belongs to the slowly irregularly variable stars .
Despite its Bayer designation , it is not the brightest star in the constellation Cetus: Beta Ceti is even brighter with a brightness of 2.04.
The star is also known under the historical proper names Menkab , Mekab , Monkar and Al Minhar . The IAU Working Group on Star Names (WGSN) defined the proper name Menkar as the standardized proper name for this star on June 30, 2016 .
See also
Web links
Individual evidence
- ^ A b F. van Leeuwen: Validation of the new Hipparcos reduction . In: Astronomy and Astrophysics . 474, No. 2, November 2007, pp. 653-664. arxiv : 0708.1752 . bibcode : 2007A & A ... 474..653V . doi : 10.1051 / 0004-6361: 20078357 .
- ↑ a b T. Tsuji: Cool luminous stars: the hybrid nature of their infrared spectra . In: Astronomy and Astrophysics . 489, No. 3, October 2008, pp. 1271-1289. arxiv : 0807.4387 . bibcode : 2008A & A ... 489.1271T . doi : 10.1051 / 0004-6361: 200809869 .
- ↑ alf Cet. In: VSX. AAVSO, accessed October 29, 2018 .
- ↑ a b c H. L. Johnson, B. Iriarte, RI Mitchell, WZ Wisniewskj: UBVRIJKL photometry of the bright stars . In: Communications of the Lunar and Planetary Laboratory . 4, No. 99, 1966. bibcode : 1966CoLPL ... 4 ... 99J .
- ↑ a b alf Cet. In: SIMBAD . Center de Données astronomiques de Strasbourg , accessed October 29, 2018 .
- ↑ B. Famaey, A. Jorissen, X. Luri, M. Mayor, S. Udry, H. Dejonghe, C. Turon: Local kinematics of K and M giants from CORAVEL / Hipparcos / Tycho-2 data. Revisiting the concept of superclusters . In: Astronomy and Astrophysics . 430, No. 1, January 2005, pp. 165-186. arxiv : astro-ph / 0409579 . bibcode : 2005A & A ... 430..165F . doi : 10.1051 / 0004-6361: 20041272 .
- ↑ a b c d e M. Wittkowski, JP Aufdenberg, T. Driebe, V. Roccatagliata, T. Szeifert, B. Wolff: Tests of stellar model atmospheres by optical interferometry. IV. VINCI interferometry and UVES spectroscopy of Menkar . In: Astronomy and Astrophysics . 460, No. 3, December 2006, pp. 855-864. arxiv : astro-ph / 0610150 . bibcode : 2006A & A ... 460..855W . doi : 10.1051 / 0004-6361: 20066032 .
- ↑ Bulletin of the IAU Working Group on Star Names, No. 1, July 2016. (PDF) Retrieved November 9, 2016 (English, 184 KiB).