Ensiklopedia Dunia

Technopedia Center

Faculty of Engineering and Computer Science
S1 Informatics S1 Information Systems S1 Information Technology S1 Computer Engineering S1 Electrical Engineering S1 Civil Engineering

faculty of Economics and Business
S1 Management S1 Accountancy

Faculty of Letters and Educational Sciences
S1 English literature S1 English language education S1 Mathematics education S1 Sports Education

Alpha Ceti - Wikipedia

Coordinates:

03^h 02^m 16.77307^s, +04° 05′ 23.0596″

From Wikipedia, the free encyclopedia

α Ceti
Observation data Epoch J2000 Equinox J2000
Location of α Ceti (circled)
Constellation	Cetus
Right ascension	03^h 02^m 16.77307^s^[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 (R_v)	−26.08±0.02^[5] km/s
Proper motion (μ)	RA: −10.41±0.51^[1] mas/yr Dec.: −76.85±0.36^[1] mas/yr
Parallax (π)	13.09 ± 0.44 mas^[1]
Distance	249 ± 8 ly (76 ± 3 pc)
Absolute bolometric magnitude (M_bol)	−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
Menkar, 92 Ceti, HR 911, BD+03°419, HD 18884, SAO 110920, FK5 107, HIP 14135
Database references
SIMBAD	data

Alpha Ceti (α Ceti, abbreviated Alpha Cet, α Cet), officially named Menkar /ˈmɛŋkɑːr/,^[9]^[10] is the second-brightest star in the constellation of Cetus. It is a cool luminous red giant estimated to be about 250 light years away based on parallax.

Nomenclature

Alpha 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 γ Cet (Kaffaljidhma), δ Cet, λ Cet (also Menkar), μ Cet, ξ¹ Cet and ξ² Cet were Al Kaff al Jidhmah, "the Part of a Hand".^[13]

In Chinese, 天囷 (Tiān Qūn), meaning Circular Celestial Granary, refers to an asterism consisting of α Ceti, κ¹ Ceti, λ Ceti, μ Ceti, ξ¹ Ceti, ξ² Ceti, ν Ceti, γ Ceti, δ Ceti, 75 Ceti, 70 Ceti, 63 Ceti and 66 Ceti. Consequently, the Chinese name for α Ceti itself is 天囷一 (Tiān Qūn yī, English: the First Star of Circular Celestial Granary.)^[14]

Characteristics

A light curve for Alpha Ceti, plotted from *Hipparcos* data,^[15] folded with the period derived by Koen and Eyer (2002)^[16]

Despite having the Bayer designation α Ceti, at visual magnitude 2.54 this star is actually not the brightest star in the constellation Cetus. That honor goes instead to Beta Ceti at magnitude 2.04. Menkar is a red giant with a stellar classification of M1.5 IIIa.^[4] It has more than twice the mass of the Sun^[6] and, as a giant star, has expanded to about 100 times the Sun's radius.^[7] The large area of the photosphere means that it is emitting about 1,765 times as much energy as the Sun, even though the effective temperature is only 3,738 K (compared to 5,778 K on the Sun).^[7] The relatively low temperature gives Menkar the red hue of an M-type star.^[17]

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

Menkar (AK-123) was a United States Navy Crater class cargo ship named after the star.

References

^ ^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.
^ "IAU Catalog of Star Names". Retrieved 28 July 2016.
^ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
^ "Bulletin of the IAU 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 Archived 2012-02-04 at the Wayback Machine
^ "/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

Assorted figures related to Alpha Ceti

Constellation of Cetus

Stars

Bayer	α (Menkar) β (Diphda) γ (Kaffaljidhma) δ ε ζ (Baten Kaitos) η θ ι κ¹ κ² λ μ ν ξ¹ ξ² ο (Mira) A B π ρ σ τ υ φ¹ φ² φ³ φ⁴ χ
Flamsteed	1 2 3 6 7 9 13 14 20 46 49 56 (υ¹) 63 64 69 75 77 79 81 84 94 25 Ari
Variable	T UV YZ ZZ AY BL BW DK
HR	10 72 159 228 500 672 870
HD	984 1690 2638 4747 5319 6718 7449 11506 11964 15115 16008 224693 (Axólotl)
Other	2MASS J01225093−2439505 BD-07 436 BD−17 63 (Felixvarela) Cayrel's Star CFBDS J005910.90–011401.3 DENIS-P J020529.0−115925 GD 40 Gliese 65 Gliese 105 GJ 1002 GJ 1005 HIP 5158 HIP 11952 LHS 1140 NGC 156 NGC 158 NGC 302 NGC 308 NGC 310 PSR J0108−1431 SDSS J001820.5−093939.2 SDSS J0106−1000 ULAS J003402.77−005206.7 WD J2356−209 WASP-20 WASP-26 WASP-44 WASP-71 (Mpingo) WISE J0254+0223 WHL0137-LS

Exoplanets	79 Ceti b 81 Ceti b 94 Ceti b BD−17 63 b HD 1461 b HD 2638 b HD 5319 b HD 11506 b c HD 11964 b c HD 224693 b HIP 5158 b c HIP 11915 b τ Ceti e f

Nebulae	NGC 246

Galaxies

Messier	77
NGC	17 35 45 47 50 54 59 61 62 64 65 66 73 77 102 107 113 114 116 117 118 120 124 132 135 142 143 144 145 151 154 155 157 161 163 165 166 167 168 170 171 172 173 177 178 179 187 191 192 195 196 197 201 207 209 210 216 217 219 223 227 230 232 235 237 239 244 245 247 255 259 263 268 270 271 273 274 275 276 277 279 283 284 285 286 291 293 297 298 301 303 307 309 320 321 325 327 329 331 333 335 336 337 340 341 342 343 344 345 347 349 350 351 352 353 355 356 357 359 363 364 367 369 377 391 413 417 426 428 429 430 435 442 445 448 450 478 480 481 487 493 497 519 521 533 540 541 545 547 554 555 560 570 584 585 596 615 622 655 681 682 690 701 720 747 755 779 800 806 833 838 864 874 880 895 908 936 945 950 960 965 966 985 988 1009 1015 1019 1022 1032 1042 1052 1055 1073 1087 1090 1128 1142 1153 1218 7808 7828 7829
Other	Arp 146 Arp 147 Arp 256 3C 75 Cetus Dwarf HCM-6A HD2 Holmberg 15A HXMM01 IC 1613 IC 1623 IRAS 01003-2238 Markarian 1014 Markarian 1018 MCG -03-04-014 PGC 2456 SDSS J0303-0019 SXDF-NB1006-2 9Spitch TON S180 UGC 711 UGC 1775 Wolf–Lundmark–Melotte

Galaxy clusters	Abell 133 Abell 222 Abell 223 Abell 370 Abell 400 Arp 251 Gioiello IRC 0218 JKCS 041

Astronomical events	SN 2005E SN 2005gj