75 Ceti: Difference between revisions
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'''75 Ceti''' is a single<ref name=Eggleton2008/> [[star]] in the [[celestial equator|equatorial]] [[constellation]] of [[Cetus]] with at least one planet.<ref name="Sato2012"/> It is visible to the naked eye as a dim, orange-hued star with an [[apparent visual magnitude]] of +5.36.<ref name=Anderson2012/> The star is located 271 [[light year]]s distant from the Sun, based on [[stellar parallax|parallax]], but is drifting closer with a [[radial velocity]] of −6 km/s.<ref name=GaiaDR2/> |
'''75 Ceti''' is a single<ref name=Eggleton2008/> [[star]] in the [[celestial equator|equatorial]] [[constellation]] of [[Cetus]] with at least one planet.<ref name="Sato2012"/> It is visible to the naked eye as a dim, orange-hued star with an [[apparent visual magnitude]] of +5.36.<ref name=Anderson2012/> The star is located 271 [[light year]]s distant from the Sun, based on [[stellar parallax|parallax]], but is drifting closer with a [[radial velocity]] of −6 km/s.<ref name=GaiaDR2/> |
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In [[Chinese language|Chinese]], {{lang|zh|天囷}} ({{lang|zh-Latn|Tiān Qūn}}), meaning ''[[Stomach (Chinese constellation)|Circular Celestial Granary]]'', refers to an asterism consisting of [[Alpha Ceti|α Ceti]], [[Kappa1 Ceti|κ<sup>1</sup> Ceti]], [[Lambda Ceti|λ Ceti]], [[Mu Ceti|μ Ceti]], [[Xi1 Ceti|ξ<sup>1</sup> Ceti]], [[Xi2 Ceti|ξ<sup>2</sup> Ceti]], [[Nu Ceti|ν Ceti]], [[Gamma Ceti|γ Ceti]], [[Delta Ceti|δ Ceti]], 75 Ceti, [[70 Ceti]], [[63 Ceti]] and [[66 Ceti]]. Consequently, 75 Ceti itself is known as the Tenth Star of Circular Celestial Granary.<ref>{{ |
In [[Chinese language|Chinese]], {{lang|zh|天囷}} ({{lang|zh-Latn|Tiān Qūn}}), meaning ''[[Stomach (Chinese constellation)|Circular Celestial Granary]]'', refers to an asterism consisting of [[Alpha Ceti|α Ceti]], [[Kappa1 Ceti|κ<sup>1</sup> Ceti]], [[Lambda Ceti|λ Ceti]], [[Mu Ceti|μ Ceti]], [[Xi1 Ceti|ξ<sup>1</sup> Ceti]], [[Xi2 Ceti|ξ<sup>2</sup> Ceti]], [[Nu Ceti|ν Ceti]], [[Gamma Ceti|γ Ceti]], [[Delta Ceti|δ Ceti]], 75 Ceti, [[70 Ceti]], [[63 Ceti]] and [[66 Ceti]]. Consequently, 75 Ceti itself is known as the Tenth Star of Circular Celestial Granary.<ref>{{in lang|zh}} [http://aeea.nmns.edu.tw/2006/0607/ap060711.html AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 11 日]</ref> |
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This is an aging [[giant star]] with a [[stellar classification]] of K1 III,<ref name=Houk1999/> having exhausted the supply of hydrogen at its [[stellar core|core]] and expanded to 10.6<ref name=GaiaDR2/> times the [[Sun's radius]], or {{Convert|10.6|solar radius|AU|2|disp=out|lk=on}}. It is a [[red clump]] giant,<ref name=Gallenne2018/> which indicates it is on the [[horizontal branch]] and is generating energy through [[helium fusion]] at the core. The star is 1.4<ref name=Gallenne2018/> billion years old with 1.9<ref name=Gallenne2018/> times the [[Sun's mass]]. It is radiating 56<ref name=GaiaDR2/> times the [[luminosity of the Sun]] from its swollen [[photosphere]] at an [[effective temperature]] of 4,846 K.<ref name=GaiaDR2/> |
This is an aging [[giant star]] with a [[stellar classification]] of K1 III,<ref name=Houk1999/> having exhausted the supply of hydrogen at its [[stellar core|core]] and expanded to 10.6<ref name=GaiaDR2/> times the [[Sun's radius]], or {{Convert|10.6|solar radius|AU|2|disp=out|lk=on}}. It is a [[red clump]] giant,<ref name=Gallenne2018/> which indicates it is on the [[horizontal branch]] and is generating energy through [[helium fusion]] at the core. The star is 1.4<ref name=Gallenne2018/> billion years old with 1.9<ref name=Gallenne2018/> times the [[Sun's mass]]. It is radiating 56<ref name=GaiaDR2/> times the [[luminosity of the Sun]] from its swollen [[photosphere]] at an [[effective temperature]] of 4,846 K.<ref name=GaiaDR2/> |
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Revision as of 00:42, 6 January 2020
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cetus |
| Right ascension | 02h 32m 09.42277s[1] |
| Declination | −01° 02′ 05.6245″[1] |
| Apparent magnitude (V) | +5.36[2] |
| Characteristics | |
| Spectral type | K1 III[3] |
| B−V color index | +1.004±0.002[2] |
| Astrometry | |
| Radial velocity (Rv) | −6.21±0.13[1] km/s |
| Proper motion (μ) | RA: −23.619[1] mas/yr Dec.: −30.485[1] mas/yr |
| Parallax (π) | 12.0264 ± 0.1044 mas[1] |
| Distance | 271 ± 2 ly (83.2 ± 0.7 pc) |
| Absolute magnitude (MV) | 0.808[4] |
| Details | |
| Mass | 1.85±0.05[5] M☉ |
| Radius | 10.62+0.68 −0.58[1] R☉ |
| Luminosity | 56.1±0.6[1] L☉ |
| Surface gravity (log g) | 2.67±0.04[5] cgs |
| Temperature | 4,846+163 −128[1] K |
| Metallicity [Fe/H] | 0.00±0.06[5] dex |
| Age | 1.41±0.01[5] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
75 Ceti is a single[7] star in the equatorial constellation of Cetus with at least one planet.[8] It is visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of +5.36.[2] The star is located 271 light years distant from the Sun, based on parallax, but is drifting closer with a radial velocity of −6 km/s.[1]
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, 75 Ceti itself is known as the Tenth Star of Circular Celestial Granary.[9]
This is an aging giant star with a stellar classification of K1 III,[3] having exhausted the supply of hydrogen at its core and expanded to 10.6[1] times the Sun's radius, or 0.05 AU. It is a red clump giant,[5] which indicates it is on the horizontal branch and is generating energy through helium fusion at the core. The star is 1.4[5] billion years old with 1.9[5] times the Sun's mass. It is radiating 56[1] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,846 K.[1]
The planetary companion was discovered by Doppler measurements at the Okayama Astrophysical Observatory, and announced in 2012. The planet's discoverers consider the planet, designated 75 Ceti b, to be "typical" of gas giants.[8] Note that (like many recorded planets) b takes in much more insolation than does Jupiter and, indeed, Earth.[10]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | >3 MJ | 2.1 | 691.9±3.6 | 0.117±0.048 | — | — |
There may be additional periodic factors in the data, corresponding to m sin i of around 0.4 MJ and 1 MJ, at distances of ∼0.9 AU and ∼4 AU, where i is the orbital inclination and m is the planet's actual mass. If these additional companions are confirmed, they are more irradiated than Earth as well.
References
- ^ a b c d e f g h i j k l m Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b c Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015.
- ^ a b Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey. 5. Bibcode:1999MSS...C05....0H.
- ^ Liu, Y. J.; et al. (2007). "The abundances of nearby red clump giants". Monthly Notices of the Royal Astronomical Society. 382 (2): 553–66. Bibcode:2007MNRAS.382..553L. doi:10.1111/j.1365-2966.2007.11852.x.
- ^ a b c d e f g Gallenne, A.; et al. (August 2018). "Fundamental properties of red-clump stars from long-baseline H-band interferometry". Astronomy & Astrophysics. 616: 12. arXiv:1806.09572. Bibcode:2018A&A...616A..68G. doi:10.1051/0004-6361/201833341. A68.
- ^ "75 Cet". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-08-01.
- ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x.
- ^ a b c Sato, Bun'ei; et al. (2012). "Substellar Companions to Seven Evolved Intermediate-Mass Stars". Publications of the Astronomical Society of Japan. 64 (6). 135. arXiv:1207.3141. Bibcode:2012PASJ...64..135S. doi:10.1093/pasj/64.6.135.
- ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 11 日
- ^ Square root of luminosity means that an Earth like planet would have to be >7 AU from the star.
