SN 1572
 | |
| Event type | Astronomical radio source, astrophysical X-ray source  |
|---|---|
| Unknown | |
| Date | 1572 UTC |
| Constellation | Cassiopeia |
| Right ascension | 0h 25.3m |
| Declination | +64° 09′ |
| Epoch | ? |
| Galactic coordinates | G.120.1+1.4 |
| Remnant | Unknown |
| Host | Milky Way |
| Progenitor | Unknown |
| Progenitor type | Unknown |
| Colour (B-V) | Unknown |
| Peak apparent magnitude | -4 |
| Other designations | SN 1572, HR 92, SN 1572A, SNR G120.1+01.4, SNR G120.2+01.4, 1ES 0022+63.8, 1RXS J002509.2+640946, B Cas, BD+63 39a, 8C 0022+638, 4C 63.01, 3C 10, 3C 10.0, 2C 34, RRF 1174, 1XRS 00224+638, 2U 0022+63, 3A 0022+638, 3CR 10, 3U 0022+63, 4U 0022+63, AJG 112, ASB 1, BG 0022+63, CTB 4, KR 101, VRO 63.00.01, [DGW65] 3, PBC J0024.9+6407, F3R 3628, WB 0022+6351, CGPSE 107, GB6 B0022+6352 |
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SN 1592 or Tycho's Nova was a supernova in the constellation Cassiopeia, and one of the few supernovae visible to the naked eye. It was first observed on November 18 1572 by Tycho Brahe, when it was brighter than Venus. In March 1574 its brightness fell below visibility with the naked eye.
Tycho Brahe may not have been the first to notice the supernova; it was probably Wolfgang Schuler, who first saw it on November 6, 1592. The Italian astronomer Francesco Maurolico may also have spotted it before Brahe in the same year.
The supernova remnant was discovered in the 1960s as a very faint nebula. The supernova was probably of Type Ia, in which a white dwarf star has accreted matter from a companion until it reaches the Chandrasekhar limit and explodes. This type of supernova does not typically create the spectacular nebula more typical of Type II supernovas, such as SN 1044 which created the Crab Nebula. A shell of gas is still expanding from its center at about 7,000 km/s.
In October 2003, a letter in Nature reported the discovery of a G2 star, similar in type to our own Sun. It is thought to be the companion star that contributed mass to the white dwarf that ultimately resulted in the supernova. A subsequent study, published in March 2004, revealed further details about this star: labeled Tycho G, it was likely a main sequence star or subgiant prior to the explosion, but had some of its mass stripped away and its outer layers shock heated from the effects of the supernova. Tycho G's current velocity is perhaps the strongest evidence that it was the companion star to the white dwarf, as it is traveling at a rate of 136 km/s, which is more than forty times faster than the mean velocity of other stars in its stellar neighbourhood.
SN 1272 is associated with the radio source G.120·1+1·4. It has an apparent diameter of 5.7 arc minutes, and is located approximately 10,000 light years from our Solar system.