119 Tauri: Difference between revisions
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'''119 Tauri''' ('''CE Tauri''') is a star in the [[constellation]] [[Taurus (constellation)|Taurus]]. It has a [[diameter]] about |
'''119 Tauri''' (also known as '''CE Tauri''') is a star in the [[constellation]] [[Taurus (constellation)|Taurus]]. It has a [[diameter]] about 590 times that of the [[Sun]]. CE Tauri is close enough that its distance can be determined accurately by parallax and so the actual diameter can be determined directly from the angular diameter. |
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119 Tauri has a [[stellar classification|spectral class]] of M2 and a [[luminosity class]] of Iab-Ib, intermediate between an intermediate-luminosity supergiant and a less luminous supergiant. It is approximately 1,800 [[light years]] from [[Earth]]. The star is classified as a [[semiregular variable star|semiregular]] [[variable star]] and its brightness varies from magnitude +4.23 to +4.54 with a period of 165 days.<ref name=gcvs/> With a [[colour index]] of +2.07, it is one of the reddest naked eye stars in the night sky.<ref name=ducati/> |
119 Tauri has a [[stellar classification|spectral class]] of M2 and a [[luminosity class]] of Iab-Ib, intermediate between an intermediate-luminosity supergiant and a less luminous supergiant. It is approximately 1,800 [[light years]] from [[Earth]]. The star is classified as a [[semiregular variable star|semiregular]] [[variable star]] and its brightness varies from magnitude +4.23 to +4.54 with a period of 165 days.<ref name=gcvs/> With a [[colour index]] of +2.07, it is one of the reddest naked eye stars in the night sky.<ref name=ducati/> |
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Revision as of 21:03, 7 September 2018
new.png) The sky position of 119 Tauri | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Taurus |
| Right ascension | 05h 32m 12.75251s[1] |
| Declination | +18° 35′ 39.2436″[1] |
| Apparent magnitude (V) | 4.23 - 4.54[2] |
| Characteristics | |
| Spectral type | M2Iab-Ib[2] |
| U−B color index | +2.23[3] |
| B−V color index | +2.08[3] |
| Variable type | SRc[2] |
| Astrometry | |
| Radial velocity (Rv) | +23.75[4] km/s |
| Proper motion (μ) | RA: 1.86[1] mas/yr Dec.: −4.48[1] mas/yr |
| Parallax (π) | 1.82 ± 0.26 mas[1] |
| Distance | approx. 1,800 ly (approx. 550 pc) |
| Absolute magnitude (MV) | −5.20[5] |
| Details | |
| Mass | 14.37+2.00 −2.77[6] M☉ |
| Radius | 587 - 593[6] R☉ |
| Luminosity | 66,000[6] L☉ |
| Surface gravity (log g) | +0.05+0.11 −0.17[6] cgs |
| Temperature | 3,801 - 3,820[6] K |
| Metallicity | 0.0[7] |
| Age | 13.9+1.0 −2.5[6] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
119 Tauri (also known as CE Tauri) is a star in the constellation Taurus. It has a diameter about 590 times that of the Sun. CE Tauri is close enough that its distance can be determined accurately by parallax and so the actual diameter can be determined directly from the angular diameter.
119 Tauri has a spectral class of M2 and a luminosity class of Iab-Ib, intermediate between an intermediate-luminosity supergiant and a less luminous supergiant. It is approximately 1,800 light years from Earth. The star is classified as a semiregular variable star and its brightness varies from magnitude +4.23 to +4.54 with a period of 165 days.[2] With a colour index of +2.07, it is one of the reddest naked eye stars in the night sky.[3]
CE Tauri lies 4.6 degrees off the ecliptic. This makes it a candidate for occultations by the Moon and (extremely rarely) by one of the bright planets. The star's angular diameter has been measured by lunar occultation, giving limb-darkened visible light angular diameters of 9.1±0.8 mas,[8] 10.9±1.0 mas,[9] and 9.0±0.2 mas.[10] An occultation has also been observed in H-alpha, giving a diameter of 17±1 mas, which indicates that there is circumstellar hydrogen producing emission across at least that size, nearly twice the visible diameter.[10]
The angular diameter has also been measured directly by VLBI, leading to limb-darkened diameters of 10.68±0.21 mas,[11] 9.83±0.07 mas,[12] 9.3±0.5 mas,[13] 9.97±0.08 mas,[7], 10.24±0.05 mas,[6] 9.68±0.05 mas.[6] Although CE Tauri is classified as a pulsating variable, observations using the same equipment and wavelengths have not detected significant changes in the angular diameter over time.[7] Reconstructed images of the surface show bright spots that are attributed to giant convection cells.[6]
Angular diameter measurements can be combined with absolute observed fluxes to derive an accurate effective temperature, in this case about 3,800 K. Combined with a distance, the linear size of the star can be calculated. CE Tauri is found to have a radius of around 590 R☉. Then the bolometric luminosity is the star is found to be about 66,000 L☉. Comparison with stellar evolutionary tracks shows CE Tauri to have evolved from an initial mass of 15 M☉ and to have a current mass of 14.37 M☉.[6] An alternative interpretation of observations, under the assumption that CE Tauri is an asymptotic giant branch (AGB) star, give it a current mass of 8 M☉ and a luminosity of 44,000 L☉.[7]
References
- ^ a b c d e Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
- ^ a b c d Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007–2013)". VizieR On-line Data Catalog: B/gcvs. Originally published in: 2009yCat....102025S. 1: 02025. Bibcode:2009yCat....102025S.
- ^ a b c Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237: 0. Bibcode:2002yCat.2237....0D.
- ^ Famaey, B.; Jorissen, A.; Luri, X.; Mayor, M.; Udry, S.; Dejonghe, H.; Turon, C. (2005). "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data". Astronomy and Astrophysics. 430 (1): 165–186. arXiv:astro-ph/0409579. Bibcode:2005A&A...430..165F. doi:10.1051/0004-6361:20041272.
- ^ Wasatonic, R.; Guinan, E. F. (1998). "Variations of Luminosity, Radius, and Temperature of the Pulsating Red Supergiant CE Tauri". Information Bulletin on Variable Stars. 4629: 1. Bibcode:1998IBVS.4629....1W.
{{cite journal}}: Unknown parameter|last-author-amp=ignored (|name-list-style=suggested) (help) - ^ a b c d e f g h i j Montargès, M; Norris, R; Chiavassa, A; Tessore, B; Lèbre, A; Baron, F (2018). "The convective photosphere of the red supergiant CE Tau. I. VLTI/PIONIER H-band interferometric imaging". arXiv:1802.06086 [astro-ph.SR].
- ^ a b c d Cruzalebes, P.; Jorissen, A.; Rabbia, Y.; Sacuto, S.; Chiavassa, A.; Pasquato, E.; Plez, B.; Eriksson, K.; Spang, A.; Chesneau, O. (2013). "Fundamental parameters of 16 late-type stars derived from their angular diameter measured with VLTI/AMBER". Monthly Notices of the Royal Astronomical Society. 434 (1): 437–450. arXiv:1306.3288. Bibcode:2013MNRAS.434..437C. doi:10.1093/mnras/stt1037.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ Beavers, W. I; Cadmus, R. R; Eitter, J. J (1982). "Lunar occultation stellar angular diameter measurements. III". The Astronomical Journal. 87: 818. Bibcode:1982AJ.....87..818B. doi:10.1086/113161.
- ^ White, N. M (1980). "The occultation of 119 Tauri and the effective temperatures of three M supergiants". The Astrophysical Journal. 242: 646. Bibcode:1980ApJ...242..646W. doi:10.1086/158501.
- ^ a b White, N. M; Kreidl, T. J; Goldberg, L (1982). "An Occultation Angular Diameter in H-Alpha Light". The Astrophysical Journal. 254: 670. Bibcode:1982ApJ...254..670W. doi:10.1086/159778.
- ^ Quirrenbach, A; Mozurkewich, D; Armstrong, J. T; Buscher, D. F; Hummel, C. A (1993). "Angular diameter measurements of cool giant stars in strong TiO bands and in the continuum". The Astrophysical Journal. 406: 215. Bibcode:1993ApJ...406..215Q. doi:10.1086/172432.
- ^ Dyck, H. M; Benson, J. A; Van Belle, G. T; Ridgway, S. T (1996). "Radii and Effective Temperatures for K and M Giants and Supergiants". The Astronomical Journal. 111: 1705. Bibcode:1996AJ....111.1705D. doi:10.1086/117910.
- ^ Dyck, H. M; Van Belle, G. T; Thompson, R. R (1998). "Radii and Effective Temperatures for K and M Giants and Supergiants. II". The Astronomical Journal. 116 (2): 981. Bibcode:1998AJ....116..981D. CiteSeerX 10.1.1.24.1889. doi:10.1086/300453.
