![]() Position of SN 2008ax in NGC 4490; image courtesy of Hunter Wilson | |
Event type | Supernova |
---|---|
Type Ib [1] | |
Date | 3 March 2008 |
Constellation | Canes Venatici |
Right ascension | 12h 30m 40.80s [2] |
Declination | +41° 38′ 16.1″ [2] |
Epoch | J2000.0 |
Galactic coordinates | b = 137.95°, l = +74.88° [2] |
Distance | 31 Mly (9.6 Mpc) [3] |
Source | NGC 4490 |
Peak apparent magnitude | +13.0 [4] |
SN 2008ax was a helium-rich type Ib core-collapse supernova in the interacting galaxy NGC 4490. [3] It was independently discovered on 3 March 2008 by LOSS [5] and 4 March by Koichi Itagaki. [6] The site had been monitored six hours before discovery, thus constraining the time of the explosion breakout. [3] It was the third-brightest supernova of 2008. [7] The brightness in the B-band peaked about 20 days after the explosion. [3] X-ray emissions were detected from the event, which are most likely the result of shock heating from the supernova ejecta and circumstellar material. [8]
Images of the source location made using the Hubble Space Telescope in 2011 and 2013 were used to identify the progenitor. If it was a single star, the images are compatible with a supergiant star with a class of B to mid-A type. However, this is not favored by models which indicate the progenitor had a relatively low mass of 4–5 M☉ and extended hydrogen-rich atmosphere with a radius of 30–40 R☉. An alternative, more plausible model suggests the progenitor was part of an interacting binary system where much of the atmosphere was lost through mass transfer to the companion. [1]
![]() Position of SN 2008ax in NGC 4490; image courtesy of Hunter Wilson | |
Event type | Supernova |
---|---|
Type Ib [1] | |
Date | 3 March 2008 |
Constellation | Canes Venatici |
Right ascension | 12h 30m 40.80s [2] |
Declination | +41° 38′ 16.1″ [2] |
Epoch | J2000.0 |
Galactic coordinates | b = 137.95°, l = +74.88° [2] |
Distance | 31 Mly (9.6 Mpc) [3] |
Source | NGC 4490 |
Peak apparent magnitude | +13.0 [4] |
SN 2008ax was a helium-rich type Ib core-collapse supernova in the interacting galaxy NGC 4490. [3] It was independently discovered on 3 March 2008 by LOSS [5] and 4 March by Koichi Itagaki. [6] The site had been monitored six hours before discovery, thus constraining the time of the explosion breakout. [3] It was the third-brightest supernova of 2008. [7] The brightness in the B-band peaked about 20 days after the explosion. [3] X-ray emissions were detected from the event, which are most likely the result of shock heating from the supernova ejecta and circumstellar material. [8]
Images of the source location made using the Hubble Space Telescope in 2011 and 2013 were used to identify the progenitor. If it was a single star, the images are compatible with a supergiant star with a class of B to mid-A type. However, this is not favored by models which indicate the progenitor had a relatively low mass of 4–5 M☉ and extended hydrogen-rich atmosphere with a radius of 30–40 R☉. An alternative, more plausible model suggests the progenitor was part of an interacting binary system where much of the atmosphere was lost through mass transfer to the companion. [1]