WR 102ka
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Star WR 102ka |
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| The surroundings of WR 102ka, the Peony Nebula, as seen by the Spitzer Space Telescope | |||||
| AladinLite | |||||
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Observation dates equinox : J2000.0 , epoch : J2000.0 |
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| Constellation | Sagittarius | ||||
| Right ascension | 17 h 46 m 18.1 s | ||||
| declination | -29 ° 01 ′ 36.6 ″ | ||||
| Typing | |||||
| Spectral class | WN10 | ||||
| Astrometry | |||||
| distance | 26,000 ly 8,000 pc |
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| Physical Properties | |||||
| Dimensions | ≈100 (initial: 150–200) M ☉ | ||||
| radius | ≈100 R ☉ | ||||
| Luminosity |
≈ 3,200,000 L ☉ |
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Other names and catalog entries |
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WR 102ka , also known as the Peony Nebula Star , is a very massive star of about 100 solar masses in the constellation Sagittarius . It is a blue hypergiant belonging to the class of Wolf-Rayet stars . It is one of the most luminous stars in the Milky Way .
The star, some 26,000 light years away, was discovered near the center of our galaxy with the help of the Spitzer Space Telescope . It got its name from the surrounding fog of the same name, whose appearance is reminiscent of the flowers of peonies .
Physical Properties
WR 102ka can not be observed in visible light . Only observations in the infrared spectral range by Spitzer made it visible.
With the help of the 3.6 meter New Technology Telescope (NTT) of the European Southern Observatory ( ESO ) in Chile, the brightness of WR 102ka could be determined more closely. According to measurements, it reaches 3.2 million times the luminosity of our sun, although the absolute luminosity is very difficult to determine, which is why it is quite possible that it has a luminosity similar to Eta Carinae .
WR 102ka belongs to the WN type of Wolf-Rayet stars, which mainly shows emission lines from nitrogen .
development
The most luminous stars are also the most massive. Researchers assume that the peony nebula began its existence as a luminous blue variable (LBV) with 150–200 solar masses. Such extremely massive stars are extremely rare and puzzles researchers to this day, as their mass is actually above the maximum limit for a single star (see Eddington limit as the theoretical maximum limit for star mass or Humphreys-Davidson limit ). Beyond this limit, a star generates so much radiation that it can no longer hold its matter together, as the radiation pressure acting outwards overcomes the force of gravity acting inwards and thus repels its outer layers. The star would break apart into double or multiple stars .
Today it is one of the Wolf-Rayet stars and still has a mass of around 100 solar masses. It has about 100 times the diameter of our central star . WR stars are characterized by the fact that they repel large amounts of matter into their surroundings, resulting in a significant loss of mass. These stellar winds are greatly accelerated by the star's radiation and reach speeds of up to 1.6 million kilometers per hour, whereby it can lose some solar masses within tens of thousands to millions of years.
Astronomers are certain that after its life of only a few million years, WR 102ka will explode in a supernova , presumably of the SN Ic type . As a result of the explosion, it will shine brighter than all the other stars in the Milky Way combined for some time, but this will not be observable from Earth as the dust and fog surrounding it will absorb almost all of the light.
See also
Individual evidence
- ↑ a b WR 102ka. In: SIMBAD . Center de Données astronomiques de Strasbourg , accessed October 29, 2018 .
- ↑ a b L. M. Oskinova, M. Steinke, W. - R. Hamann, A. Sander, H. Todt, A. Liermann: One of the most massive stars in the Galaxy may have formed in isolation . In: Monthly Notices of the Royal Astronomical Society . 436, No. 4, 2013, p. 3357. arxiv : 1309.7651 . bibcode : 2013MNRAS.436.3357O . doi : 10.1093 / mnras / stt1817 .
- ↑ a b Spitzer - second brightest star in the Milky Way discovered? , Astronews, July 16, 2008
- ↑ a b c Brightest Star in the Galaxy Has New Competition , NASA Jet Propulsion Laboratory, Pasadena, California, USA, July 15, 2008
- ↑ a b Blue Giant second brightest star in the Milky Way , Scinexx / Springer, March 30, 2011
- ↑ a b One of the brightest stars in our Milky Way system , Astronomy Today, July 16, 2008