SN 2008ax

SN 2008ax
Position of SN 2008ax in NGC 4490; image courtesy of Hunter Wilson
Event typeSupernova
Type Ib[1]
Date3 March 2008
ConstellationCanes Venatici
Right ascension12h 30m 40.80s[2]
Declination+41° 38′ 16.1″[2]
EpochJ2000.0
Galactic coordinatesb = 137.95°, l = +74.88°[2]
Distance31 Mly (9.6 Mpc)[3]
SourceNGC 4490
Peak apparent magnitude+13.0[4]
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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]

  1. ^ a b Cite error: The named reference Folatelli_et_al_2015 was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference Drake_et_al_2009 was invoked but never defined (see the help page).
  3. ^ a b c d Cite error: The named reference Pastorello_et_al_2008 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference SN2008ax was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Mostardi_et_al_2008 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Nakano2008 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference supernovae2008 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Roming_et_al_2009 was invoked but never defined (see the help page).