V404 Cygni
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Double star V404 Cygni |
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| X-ray of the Nova from 2015 at V404 Cygni | |||
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Observation dates equinox : J2000.0 , epoch : J2000.0 |
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| Constellation | swan | ||
| Right ascension | 20 h 24 m 3.82 s | ||
| declination | + 33 ° 52 ′ 1.9 ″ | ||
| Apparent brightness | 12.7 mag 11.2 to 18.8 mag |
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| Typing | |||
| B − V color index | +1.50 | ||
| U − B color index | +0.30 | ||
| Spectral class | Black Hole + K0 IV | ||
| Astrometry | |||
| distance | (2390 ± 140) pc | ||
| Visual absolute brightness M vis | +3.4 mag | ||
| Physical Properties | |||
| Dimensions | 9 / 0.7 M ☉ | ||
| radius | ? / 6 R ☉ | ||
| Luminosity |
? / 10.2 L ☉ |
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Other names and catalog entries |
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V404 Cygni is a binary star system that probably contains a black hole . The companion star, with a spectral class between late G and early K, has a mass that is slightly smaller than the sun. The double star lies in the constellation Swan . The two stars orbit each other at a relatively short distance every 6.5 days.
properties
The more massive component, which is presumably a black hole, was estimated as early as 1994 to be 12 ± 3 solar masses . Later works assume a mass of about 9 solar masses. However, it could also be that the more massive component is a quark star instead of a black hole .
The companion is probably a subgiant with a slightly lower mass than the sun , but about 10 times more luminosity.
Together, the two components form a so-called low-mass X-ray binary (LMXB) as well as a microquasar .
history
On May 22, 1989, the Japanese Ginga satellite discovered a new X-ray source, cataloged as GS 2023 + 338. This was then identified with the previously known Nova V404 Cygni from 1938 because the position coincided.
In 2009, the putative black hole in the V404 Cygni system was the first to have an accurate parallax measurement for its distance from our solar system. The distance is 2.39 ± 0.14 kiloparsecs .
Nova 2015
At 6:31 p.m. Greenwich Mean Time on June 15, 2015, new activity was detected by the Swift satellite . As a result, it was possible to observe on V404 Cygni how visible light came in the form of lightning bolts from the black hole as it absorbed mass from its partner star. The X-rays released when entering the black hole heated the remaining material so that it became visible. If it had not been obscured by interstellar dust, the black hole would have been one of the brightest objects in the Milky Way as of June 2015 that would have been visible even to the naked eye. Telescopes with a mirror size of 20 cm were sufficient for observation.
literature
- Elena P. Pavlenko, Yuliana G. Kuznetsova, Sergei Yu. Shugarov and Vladislav S. Petrov: V404 Cyg: 10 years in quiescence
- RM Wagner, S. Starrfield, A. Cassatella, R. Gonzalez-Riestra, TJ Kreidl, SB Howell, RM Hjellming, X. -H. Han, G. Sonneborn: The 1989 outburst of V404 cygni: A very unusual x-ray nova
Web links
- Spektrum .de: Black Hole Out of Control April 29, 2019
Individual evidence
- ↑ a b c d V404 Cyg. In: SIMBAD . Center de Données astronomiques de Strasbourg , accessed September 9, 2018 .
- ↑ a b V0404 Cyg. In: VSX. AAVSO, accessed September 9, 2018 .
- ^ A b Miller-Jones, JAC, Jonker, Dhawan: The first accurate parallax distance to a black hole . In: The Astrophysical Journal Letters . 706, No. 2, August, p. L230. arxiv : 0910.5253 . bibcode : 2009ApJ ... 706L.230M . doi : 10.1088 / 0004-637X / 706/2 / L230 .
- ↑ a b c d e T. Shahbaz, FA Ringwald, JC Bunn, T. Naylor, PA Charles, J. Casares: The mass of the black hole in V404 Cygni . In: Monthly Notices of the Royal Astronomical Society . 271, 1994, p. L10. bibcode : 1994MNRAS.271L..10S . doi : 10.1093 / mnras / 271.1.L10 .
- ^ A b F. Bernardini, DM Russell, AW Shaw, F. Lewis, PA Charles, KII Koljonen, JP Lasota, J. Casares: Events leading up to the 2015 June Outburst of V404 Cyg . In: The Astrophysical Journal Letters . 818, 2016, p. L5. arxiv : 1601.04550 . bibcode : 2016ApJ ... 818L ... 5B . doi : 10.3847 / 2041-8205 / 818/1 / L5 .
- ↑ Shahbaz, T., FA Ringwald, JC Bunn, T. Naylor, PA Charles, J. Casares: The mass of the black hole in V404 Cygni . In: MNRAS . 271, 1994, pp. L1-L14. bibcode : 1994MNRAS.271L..10S .
- ↑ Ian Sample Visible light from black holes detected for first time in: The Guardian, January 6, 2016, accessed January 6, 2016
- ↑ Repetitive patterns in rapid optical variations in the nearby black-hole binary V404 Cygni in: Nature 529, pp. 54–58, January 7, 2016, advance publication online on January 6, 2016, accessed on January 6, 2016