Unmasking the Supernova Impostors

  title={Unmasking the Supernova Impostors},
  author={Christopher S. Kochanek and Dorota M. Szczygiel and K. Z. Stanek Department of Astronomy and the Center for Cosmology and Astroparticle Physics and The Ohio State University},
  journal={The Astrophysical Journal},
The canonical picture of a supernova impostor is a short (~months) –11 MV –14 optical transient from a massive (M * 40 M ☉) star during which the star ejects a dense shell of material. Dust formed in the ejecta then obscures the star. In this picture, the geometric expansion of the shell leads to clear predictions for the evolution of the optical depths and hence the evolution of the optical through mid-IR emissions. Here, we review the theory of this standard model and then examine the… 
SN 2009ip and SN 2010mc: core-collapse Type IIn supernovae arising from blue supergiants
The recent supernova (SN) known as SN 2009ip had dramatic precursor eruptions followed by an even brighter explosion in 2012. Its pre-2012 observations make it the best documented SN progenitor in
SN 2002bu?Another SN 2008S-like Transient
We observed supernova (SN) 2002bu in the near-IR with the Hubble Space Telescope (HST), the mid-IR with the Spitzer Space Telescope, and in X-rays with Swift 10 years after the explosion. If the
Deep late-time observations of the supernova impostors SN 1954J and SN 1961V
SN 1954J in NGC 2403 and SN 1961V in NGC 1058 were two luminous transients whose definitive classification as either non-terminal eruptions or supernovae remains elusive. A critical question is
SN Hunt 248: a super-Eddington outburst from a massive cool hypergiant
We present observations of SN Hunt 248, a new supernova (SN) impostor in NGC 5806, which began a multistage outburst in 2014 May. The ‘2014a’ discovery brightening exhibited an absolute magnitude of
LOSS's first supernova? New limits on the ‘impostor’ SN 1997bs
We present new, late-time Hubble Space Telescope and Spitzer Space Telescope observations of the archetypal supernova (SN) impostor SN 1997bs. We show that SN 1997bs remains much fainter than its
Type IIn supernovae (SNe IIn) are a rare (<10%) subclass of core-collapse SNe that exhibit relatively narrow emission lines from a dense, pre-existing circumstellar medium (CSM). In 2009, a warm
Supernova progenitors, their variability and the Type IIP Supernova ASASSN-16fq in M66
We identify a pre-explosion counterpart to the nearby Type IIP supernova ASASSN-16fq (SN 2016cok) in archival Hubble Space Telescope data. The source appears to be a blend of several stars that
The Rise of the Remarkable Type IIn Supernova SN 2009ip
Recent observations by Mauerhan et al. have shown the unprecedented transition of the previously identified luminous blue variable (LBV) and supernova (SN) impostor SN 2009ip to a real Type IIn SN
The Intermediate Luminosity Optical Transient SN 2010da: The Progenitor, Eruption and Aftermath of a Peculiar Supergiant High-mass X-ray Binary
We present optical spectroscopy, ultraviolet to infrared imaging and X-ray observations of the intermediate luminosity optical transient (ILOT) SN 2010da in NGC 300 (d=1.86 Mpc) spanning from -6 to
The dusty aftermath of SN Hunt 248: merger-burst remnant?
SN Hunt 248 was classified as a non-terminal eruption (a supernova ‘impostor’) from a directly identified and highly variable cool hypergiant star. The 2014 outburst achieved peak luminosity


We present visual-wavelength photometry and spectroscopy of supernova (SN) 2008S. Based on the low peak luminosity for a SN of MR = –13.9 mag, photometric and spectral evolution unlike that of
Faint supernovae and supernova impostors: case studies of SN 2002kg/NGC 2403-V37 and SN 2003gm
Photometric and spectroscopic observations of the faint Supemovae (SNe) 2002kg and 2003gm, and their precursors, in NGC 2403 and NGC 5334 respectively, are presented. The properties of these SNe are
SN 1997bs in M66: Another Extragalctic n Crinae Analog?
ABSTRACT We report on SN 1997bs in NGC 3627 (M66), the first supernova discovered by the Lick Observatory Supernova Search using the 0.75 m Katzman Automatic Imaging Telescope (KAIT). Based on its
A Hubble Space Telescope Snapshot survey of nearby supernovae
We present photometry of 13 recent supernovae (SNe) recovered in a Hubble Space Telescope Snapshot program and tie the measurements to earlier ground-based observations in order to study the
SN 2002kg – the brightening of LBV V37 in NGC 2403
SN 2002kg is a type IIn supernova, detected in October 2002 in the nearby spiral galaxy NGC 2403. We show that the position of SN 2002kg agrees within the errors with the position of the LBV V37.
Discovery of the Dust-Enshrouded Progenitor of SN 2008S with Spitzer
We report the discovery of the progenitor of the recent Type IIn SN 2008S in the nearby galaxy NGC 6946. Surprisingly, it was not found in deep, preexplosion optical images of its host galaxy taken
It's Alive! The Supernova Impostor 1961V
Reports of the death of the precursor of supernova (SN) 1961V in NGC 1058 are exaggerated. Consideration of the best astrometric data shows that the star, known as "Object 7," lies at the greatest
The massive binary companion star to the progenitor of supernova 1993J
Photometric and spectroscopic observations of SN1993J ten years after the explosion detect the unambiguous signature of a massive star: the binary companion to the progenitor.
SN 2008S: An electron-capture SN from a super-AGB progenitor?
We present comprehensive photometric and spectroscopic observations of the faint transient SN 2008S discovered in the nearby galaxy NGC 6946. SN 2008S exhibited slow photometric evolution and almost
SN 2006jc: A Wolf-Rayet Star Exploding in a Dense He-rich Circumstellar Medium
We present optical photometry and spectra of the peculiar Type Ib supernova (SN) 2006jc. Strong and relatively narrow He I emission lines indicate the progenitor star exploded inside a dense