119 Tauri
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Star 119 Tauri / CE Tauri |
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| Position of 119 Tauri in the constellation Taurus | |||||||||||||||||||
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Observation dates equinox : J2000.0 , epoch : J2000.0 |
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| Constellation | bull | ||||||||||||||||||
| Right ascension | 05 h 32 m 12.8 s | ||||||||||||||||||
| declination | + 18 ° 35 ′ 39 ″ | ||||||||||||||||||
| Apparent brightness | 4.37 likes | ||||||||||||||||||
| Typing | |||||||||||||||||||
| B − V color index | +2.06 | ||||||||||||||||||
| U − B color index | +2.21 | ||||||||||||||||||
| R − I index | +1.44 | ||||||||||||||||||
| Spectral class | M2 Iab-Ib | ||||||||||||||||||
| Variable star type | semi-regular (SRc) | ||||||||||||||||||
| Astrometry | |||||||||||||||||||
| Radial velocity | (+23.75 ± 0.44) km / s | ||||||||||||||||||
| parallax | (1.82 ± 0.26) mas | ||||||||||||||||||
| distance | (1800 ± 300) ly (550 ± 80) pc |
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| Visual absolute brightness M vis | approx. −5 mag | ||||||||||||||||||
| Proper movement | |||||||||||||||||||
| Rec. Share: | approx. 0 mas / a | ||||||||||||||||||
| Dec. portion: | approx. −5 mas / a | ||||||||||||||||||
| Physical Properties | |||||||||||||||||||
| Dimensions | 12 to 15 M ☉ | ||||||||||||||||||
| radius | (600) R ☉ | ||||||||||||||||||
| Luminosity |
(42000) L ☉ |
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| Effective temperature | (3400) K | ||||||||||||||||||
| Metallicity [Fe / H] | +0.11 (≈ 130% of the sun) |
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Other names and catalog entries |
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119 Tauri , also known as CE Tauri , is a red supergiant of the spectral class M2 about 2000 light-years away . It is part of the constellation Taurus (Taurus).
Visual appearance
Due to the low surface temperature of around 3,400 Kelvin , 119 Tauri appears reddish. With a noticeably high B − V color index of 2.06, it has an extraordinarily reddish color. Only μ Cephei, Herschel's “ garnet star ”, has an even higher color index as a star that is visible to the naked eye. Other very red stars, such as R Leporis or La Superba (Y CVn), are not always visible to the naked eye because of their variable brightness.
Designations
"119 Tauri" is the Flamsteed name of the star. The British astronomer John Flamsteed numbered the stars visible with the naked eye in ascending order according to their right ascension , according to which the right ascension of 119 Tauri is higher than that of the main star of the constellation Taurus, Aldebaran (87 tau).
The designation "CE Tauri" follows the rules for naming variable stars : The first part of the name "CE" means that 119 Tauri is the 144th variable star discovered in the constellation Taurus; the second part of the name "Tauri" is the genitive of the Latin name of the constellation.
position
119 Tauri is part of Taurus (Latin: Taurus ), a constellation of the ecliptic that can be observed from both the northern and southern hemispheres of the earth. This constellation is, viewed from the earth, on the side facing away from the galactic center , which is in the constellation Sagittarius (Latin Sagittarius ). The light of 119 Tauri is weakened by dust clouds surrounding it or between it and the sun , including the dust clouds of the Taurus-Auriga complex, by 0.8 magnitudes. If there was no dust between the sun and Tauri, the supergiant would be a star close to the limit of the third magnitude and would appear twice as bright in the sky, comparable to the apparent brightness of ε Tauri .
distance
The parallax measured by the Hipparcos space telescope gives a value of approx. 1800 light years for the distance of the star. However, the specified measurement uncertainty only allows the value to be determined to within a few hundred light years. If the distance is at the upper limit of the measurement uncertainty, 119 Tauri would be one of the largest and most luminous stars in the Milky Way. If the lower bound is correct, it should be an ordinary red giant .
Proper movement
119 Tauri belongs to the outskirts of our galaxy, those areas in which there are many open star clusters , such as the Pleiades , and dark clouds. It has a very similar self-movement, among other things like the neighboring blue giant 120 Tauri.
Physical Properties
119 Tauri is a giant , and is due to its luminosity in Russell Hertzsprung- Chart in the luminosity class divided Ib. It belongs to the spectral class M, but belongs to an earlier subtype with M2 and is therefore not counted among the cool supergiants like V838 Monocerotis .
As is often the case with heavy stars, its physical values are very uncertain and therefore cannot be clearly determined. It is believed to have some resemblance to Betelgeuse . Its radius is estimated at 600 solar radii , which corresponds to a rounded diameter of 835 million kilometers or 5.6 AU . If 119 Tauri were at the center of the solar system , it would protrude beyond the orbit of the planet Mars and fill more than 50% of Jupiter's distance from the sun. The luminosity of this star is estimated to be 50,000 times that of the sun.
The apparent magnitude of 119 Tauri changes by 0.3 mag with a semi-regular period (type SRc).
See also
Web links
Individual evidence
- ↑ a b c d e SIMBAD database
- ↑ a b c Bright Star Catalog
- ↑ a b Hipparcos catalog
- ↑ 119 Tauri
- ↑ a b c P Cruzalèbes, A Jorissen, Y Rabbia, S Sacuto, A Chiavassa, E Pasquato, B Plez, K Eriksson, A Spang, O Chesneau: Fundamental parameters of 16 late-type stars derived from their angular diameter measured with VLTI / AMBER . In: Monthly Notices of the Royal Astronomical Society . 434, 2013, p. 437. arxiv : 1306.3288 . bibcode : 2013MNRAS.434..437C . doi : 10.1093 / mnras / stt1037 .
- ↑ Marrese et al .: "High resolution spectroscopy over λλ 8500-8750 Å for GAIA." In: Astronomy & Astrophysics , Vol. 406, pp. 995-999