Alpha Ceti (
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Cetus |
Right ascension | 03h 02m 16.77307s[1] |
Declination | +04° 05′ 23.0596″[1] |
Apparent magnitude (V) | 2.53[2] |
Characteristics | |
Evolutionary stage | AGB[3] |
Spectral type | M1.5 IIIa[4] |
U−B color index | +1.93[2] |
B−V color index | +1.64[2] |
Astrometry | |
Radial velocity (Rv) | −26.08±0.02[5] km/s |
Proper motion ( | RA: −10.41±0.51[1] mas/yr Dec.: −76.85±0.36[1] mas/yr |
Parallax ( | 13.09 ± 0.44 mas[1] |
Distance | 249 ± 8 ly (76 ± 3 pc) |
Absolute magnitude (MV) | −3.2±0.3[4] |
Details | |
Mass | 2.3±0.2;[6] 1.465–1.933[7] M☉ |
Radius | 100.2±3.4[7] R☉ |
Luminosity | 1,764±342[7] L☉ |
Surface gravity (log g) | 0.66±0.07[7] cgs |
Temperature | 3,738±170[7] K |
Metallicity [Fe/H] | −0.24±0.09[7] dex |
Rotational velocity (v sin i) | 6.9[8] km/s |
Other designations | |
Database references | |
SIMBAD | data |
Nomenclature
editAlpha Ceti is the star's Bayer designation. It has the traditional name Menkar, deriving from the Arabic word منخر manħar "nostril" (of Cetus). In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[11] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[12] included a table of the first two batches of names approved by the WGSN; which included Menkar for this star.
This star, along with
In Chinese,
Characteristics
editDespite having the Bayer designation
Menkar has evolved from the main sequence after exhausting the hydrogen at its core. It has also exhausted its core helium, becoming an asymptotic giant branch star,[3] and will probably become a highly unstable star like Mira before finally shedding its outer layers and forming a planetary nebula, leaving a relatively large white dwarf remnant.[18] It has been observed to periodically vary in brightness, but only with an amplitude of about one hundredth of a magnitude.[16]
Namesakes
editMenkar (AK-123) was a United States Navy Crater class cargo ship named after the star.
References
edit- ^ a b c d e van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600
- ^ a b c Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J
- ^ a b Eggen, Olin J. (1992), "Asymptotic giant branch stars near the sun", The Astronomical Journal, 104: 275, Bibcode:1992AJ....104..275E, doi:10.1086/116239
- ^ a b c Tsuji, T. (October 2008), "Cool luminous stars: the hybrid nature of their infrared spectra", Astronomy and Astrophysics, 489 (3): 1271–1289, arXiv:0807.4387, Bibcode:2008A&A...489.1271T, doi:10.1051/0004-6361:200809869, S2CID 19007399
- ^ Famaey, B.; et al. (January 2005), "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters", Astronomy and Astrophysics, 430 (1): 165–186, arXiv:astro-ph/0409579, Bibcode:2005A&A...430..165F, doi:10.1051/0004-6361:20041272, S2CID 17804304
- ^ a b Wittkowski, M.; et al. (December 2006), "Tests of stellar model atmospheres by optical interferometry. IV. VINCI interferometry and UVES spectroscopy of Menkar", Astronomy and Astrophysics, 460 (3): 855–864, arXiv:astro-ph/0610150, Bibcode:2006A&A...460..855W, doi:10.1051/0004-6361:20066032, S2CID 16525827
- ^ a b c d e f g h Soubiran, C.; Creevey, O. L.; Lagarde, N.; Brouillet, N.; Jofré, P.; Casamiquela, L.; Heiter, U.; Aguilera-Gómez, C.; Vitali, S.; Worley, C.; de Brito Silva, D. (2024-02-01). "Gaia FGK benchmark stars: Fundamental Teff and log g of the third version". Astronomy and Astrophysics. 682: A145. arXiv:2310.11302. Bibcode:2024A&A...682A.145S. doi:10.1051/0004-6361/202347136. ISSN 0004-6361. Menkar's database entry at VizieR.
- ^ Massarotti, Alessandro; et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209, S2CID 121883397
- ^ Kunitzsch, Paul; Smart, Tim (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2nd rev. ed.). Cambridge, Massachusetts: Sky Pub. ISBN 978-1-931559-44-7.
- ^ "I
AU Catalog of Star Names". Retrieved 28 July 2016. - ^ "I
AU Working Group on Star Names (WGSN)". Retrieved 22 May 2016. - ^ "Bulletin of the I
AU Working Group on Star Names, No. 1" (PDF). Retrieved 28 July 2016. - ^ Star Name - R.H. Allen p.160
- ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy)
天文 教育 資 訊網 2006年 7月 11日 - ^ "/ftp/cats/more/HIP/cdroms/cats". Centre de Données astronomiques de Strasbourg. Strasbourg astronomical Data Center. Retrieved 15 October 2022.
- ^ a b Koen, Chris; Eyer, Laurent (2002), "New periodic variables from the Hipparcos epoch photometry", Monthly Notices of the Royal Astronomical Society, 331 (1): 45, arXiv:astro-ph/0112194, Bibcode:2002MNRAS.331...45K, doi:10.1046/j.1365-8711.2002.05150.x
- ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on March 18, 2012, retrieved 2012-01-16
- ^ Kaler, James B., "MENKAR (Alpha Ceti)", Stars, University of Illinois, retrieved 2011-12-24
External links
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