SN 2011dh
Supernova in the Whirlpool Galaxy
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SN 2011dh was a supernova in the Whirlpool Galaxy (M51). It was discovered on 31 May 2011, with an apparent magnitude 13.5.[4] and confirmed by several sources, including the Palomar Transient Factory.[5] A candidate progenitor was detected in Hubble Space Telescope images.[9] The progenitor may have been a highly luminous yellow supergiant with an initial mass of 18-24 solar masses.[6] The supernova peaked near apparent magnitude 12.1 on 19 June 2011.[8] Emission spectra indicated that the explosion was a type II supernova, in which a massive star collapses once nuclear fusion has ceased in its core.[4]
| Event type | Supernova  |
|---|---|
| IIb[1][2] | |
| Date | 31 May 2011[3] |
| Constellation | Canes Venatici |
| Right ascension | 13h 30m 05.08s[4][5] |
| Declination | +47° 10′ 11.2″[4][5] |
| Epoch | J2000 |
| Host | Whirlpool Galaxy (M51) |
| Progenitor | ? |
| Progenitor type | yellow supergiant[6][7] |
| Colour (B-V) | ? |
| Peak apparent magnitude | 12.1[8] |
| Other designations | SN 2011dh, [RMS2015] J133005+471010 |
SN2011dh was the third supernova to be recorded in the Whirlpool galaxy since 1994 (following SN 1994I and SN 2005cs).[10] The supernova frequency in the Milky Way is estimated to be around one event every 40 years.[11]
