SN 1987A
| Supernova | |
|---|---|
| SN 1987A | |
|
|
| The Remnant of the Supernova 1987A | |
| Constellation | Swordfish |
|
Position equinox : J2000.0 |
|
| Right ascension | 05h 35m 28.03s |
| declination | −69 ° 16 ′ 11.79 ″ |
| Further data | |
| Brightness (visual) |
+3 likes |
| Brightness (B-band) |
+3,085 likes |
| distance |
168,000 ly |
| Affiliation | |
| Predecessor star |
Sanduleak -69 ° 202a |
| Predecessor star type |
B3 Supergiant |
| Type | |
| history | |
| Date of discovery |
February 24, 1987 (23:00 UTC ) |
| Catalog names | |
| Aladin previewer | |
SN 1987A is the closest supernova that has been observed since the 1604 supernova . It was discovered on February 24, 1987 and took place in the Large Magellanic Cloud (GMW). This is about 48,000 ± 5,000 parsecs away, which corresponds to around 157,000 ± 16,000 light years .
To this day, it is the most important for astrophysics because its proximity and great brightness made it possible for the first time to accurately spectroscopy such an explosion. The mechanism of SN 1987A is interpreted as a core collapse .
Predecessor star
The collision of the supernova remnants with material emitted 20,000 years ago becomes visible.
SN 1987A was the first supernova in which the predecessor star could be identified. The star that triggered the explosion with its core collapse was part of a triple star system . He was already classified in a directory of hot blue stars in the GMW by Nicholas Sanduleak before his demise . The collapsar is called Sanduleak −69 ° 202 ( Sk −69 202 for short ) and possessed about 17 solar masses. Sk −69 202 ended his life as a so-called blue supergiant . Its age at the time of the explosion is estimated to be "only" about 20 million years. During this short lifespan, it burned its energy supply compared to the sun , which is already around 5 billion years old, so many times faster.
Based on theoretical considerations, it is assumed that the core collapse of Sk −69 202 led to the formation of a neutron star . But no radiation source could be found at the location of the predecessor star, neither in the area of X-rays , radio radiation nor in the optical area. The search for a pulsed source, characteristic of a pulsar , was also unsuccessful. There are numerous hypotheses regarding the lack of a detectable neutron star, for example:
- Relapsed matter has led to the neutron star being transformed into a black hole .
- A cold cloud of dust prevents detection of the neutron star due to absorption.
- Instead of a neutron star, a quark star has formed.
The remnants of the 1987A supernova are one of the most widely studied astronomical objects today.
Neutrino emissions
Three hours before visible light reached Earth, strong neutrino emissions were detected by various neutrino observatories that had actually been operated to study neutrino oscillation and to search for proton decay . This was the first neutrino measurement on a supernova and confirmed theoretical models according to which large parts of the energy of a supernova are emitted in the form of neutrinos. Since the neutrino detectors were not sensitive enough, the full energy spectrum could not be recorded. In the Kamiokande detector, a pulse of eleven neutrinos in thirteen seconds observed eight in Irvine Michigan Brookhaven experiment , possibly five in the Mont Blanc Underground Neutrino Observatory and five in the Baksan detector These are still the only proven neutrinos which are safe from a supernova which, in turn, could be observed with telescopes a few hours later.
The neutrinos reached the earth before the light, as they can cross matter practically without interaction (i.e. unrestrained). So they left the collapsing core and the shock wave right after the event - the light from the supernova was not visible until the explosion reached the star's surface, which it did about three hours later. The difference in the arrival time of a few hours after around 157,000 years means that the speed of the neutrinos differs at most minimally from that of light.
See also
literature
- Stefan Immler: Supernova 1987A - 20 years after - supernovae and gamma-ray bursters. American Inst. Of Physics. Melville, NY 2007, ISBN 978-0-7354-0448-9 .
- Lawrence M. Krauss (1987): Neutrino spectroscopy of supernova 1987A . Nature, volume 329, pages 689–694
- Hanuschik, RW (1989): Optical Spectrophotometry of the Supernova 1987A in the LMC . Reviews in Modern Astronomy, v. 2, p. 148-166.
Web links
- Image archive at ESA / Hubble
- Image archive at AAO: Surroundings of SN 1987A during and before the eruption Direct link to a larger image
- What was left of the Supernova SN 1987A
swell
- ↑ Hubble Heritage Project : SN1987A in the Large Magellanic Cloud
- ↑ XW Liu, JD Liang, RX Xu, JL Han, and GJ Qiao: The missing compact star of SN1987A: a solid quark star? In: Astrophysics. Solar and Stellar Astrophysics . 2012, arxiv : 1201.3101v1 .
- ↑ K. Hirata et al. (KAMIOKANDE-II Collabration): Observation of a Neutrino Burst from the Supernova SN 1987A in Phys. Rev. Lett. 58 (1987), 1490-1493 doi : 10.1103 / PhysRevLett.58.1490
- ↑ RM Bionta et al .: Observation of a Neutrino Burst in Coincidence with Supernova SN 1987a in the Large Magellanic Cloud in Phys. Rev. Lett. 58 (1987), 1494 doi : 10.1103 / PhysRevLett.58.1494
- ^ M. Aglietta et al .: On the Event Observed in the Mont Blanc Underground Neutrino Observatory during the Occurrence of Supernova 1987a in Europhys. Lett. 3 : 1315-1320 (1987) doi : 10.1209 / 0295-5075 / 3/12/011
- ↑ EN Alexeyev et al. in sov. JETP Lett. 45: 461 (1987)
- ↑ Kai Zuber: Neutrino Physics . Institute of Physics Publishing, Bristol and Philadelphia 2004, ISBN 0-7503-0750-1 .