SN 1972E

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SN 1972E was a supernova discovered on May 13, 1972 in the galaxy NGC 5253 . The apparent brightness measured shortly after reaching the maximum brightness was 8.5 mag . In terms of brightness, it was the second brightest supernova of its kind in the twentieth century after SN 1987A . It was observed for almost 700 days and became the prototypical object in the development of the theoretical understanding of type Ia supernovae .

background

The supernova was discovered by Charles Kowal about 56 arc seconds west and 85 arc seconds south of NGC 5253. The location in the periphery of the galaxy minimized interference from background objects and made observations easier. The position of the object in the constellation Centaur was ideal for observers in the southern hemisphere, but it was also still observable in the northern hemisphere. Attempts to observe the supernova with the Uhuru and OSO-7 satellites in the X-ray range and to detect gamma radiation via Cherenkov radiation showers did not yield any clear results. The X-rays predicted in a model proposed by Schklowski could not be confirmed, but the model could not rule out the upper limits of the measurement results either.

Astrophotometric and spectroscopic measurements were carried out by many observers in the visible and near infrared up to around 700 days after the maximum brightness. There were interstellar absorption lines of ionized calcium in the gas both in our galaxy observed and in NGC 5253 that an estimate of the interstellar extinction allowed.

The further course of the observed light curve, from about 60 days since discovery, showed a remarkably even decrease of 0.01 mag per day. This corresponds to a half-life of almost exactly 77 days, which is equal to the half-life of cobalt isotope 56 Co is. In the standard model of the Type Ia supernovae , a white dwarf generates about a solar mass of the nickel isotope 56 Ni , accretes matter from a companion and explodes after crossing the Chandrasekhar limit . This 56 Ni decays to 56 Co with a half-life of about 6 days , and the decay of the cobalt into iron provides the energy radiated from the supernova remnant . The model also provides an estimate for the brightness of such a supernova. The observations made on SN 1972E, both of the maximum brightness and the rate of attenuation, generally agreed with the predictions and led to a rapid acceptance of the model.

See also

Individual evidence

  1. ↑ TA Lee, W. Wamsteker, WZ Wisniewski, TJ Wdowiak: Photometry of Supernova 1972 IN NGC 5253 . In: Astrophysical Journal . 177, 1972, p. L59. bibcode : 1972ApJ ... 177L..59L . doi : 10.1086 / 181052 .
  2. ↑ AH Jarrett: The Supernova in NGC 5253 . In: Information Bulletin on Variable Stars . No. 828, September 21, 1973.
  3. ↑ A. Ardeberg, M. de Groot: The 1972 supernova in NGC 5253. Photometric results from the first observing season . In: Astronomy & Astrophysics . 28, 1973, pp. 295-304. bibcode : 1973A & A .... 28..295A .
  4. ↑ a b C. R. Canzares, JE Neighbors, T. Matilsky: A Search for X-Rays from Supernova 1972e with UHURU and OSO-7 . In: Astrophysical Journal . 192, 1974, p. L61. bibcode : 1974ApJ ... 192L..61C . doi : 10.1086 / 181591 .
  5. ↑ a b c M. P. Ulmer, WA Baity, WA Wheaton, LE Peterson: Upper limit to the X-ray flux from the supernova in NGC 5253 above 7 keV from the OSO-7 . In: Astrophysical Journal . 193, Nov. 1, 1974, pp. 535-537. bibcode : 1974ApJ ... 193..535U . doi : 10.1086 / 153191 .
  6. ↑ RP Kirshner, JB Oke: Supernova 1972e in NGC 5253 . In: Astrophysical Journal . 200, September 15, 1975, pp. 574-581. bibcode : 1975ApJ ... 200..574K . doi : 10.1086 / 153824 .
  7. ↑ PS Osmer, JE Hesser, WE Kunkel, BM Lasker, MF McCarthy: Optical Observations of the supernova in NGC 5253 . In: Nature . 238, July 10, 1972, pp. 21-22. bibcode : 1972NPhS..238 ... 21O . doi : 10.1038 / physci238021a0 .
  8. ^ Virginia Trimble: Supernovae. Part I: the events . In: Reviews of Modern Physics . 54, Oct 1982, pp. 1183-1224. bibcode : 1982RvMP ... 54.1183T . doi : 10.1103 / RevModPhys.54.1183 .

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