NOAO >   Observing Info >   Approved Programs >   2012A-0388

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Proposal Information for 2012A-0388


PI: Howard E. Bond, Space Telescope Science Institute, bond@stsci.edu
Address: 3700 San Martin Drive, Baltimore, MD 21218, USA

Title: Intermediate-Luminosity Red Transients: SMARTS Monitoring

Abstract: A new class of intermediate-luminosity red transients (ILRTs) has been recognized recently, with maximum brightnesses between those of classical novae (CNe) and supernovae (SNe). During their outbursts, they evolve to extremely red colors, completely unlike CNe. A prototype is the Galactic star V838 Monocerotis, whose 2002 outburst illuminated a spectacular light echo, imaged by \it HST \null. Polarimetric imaging of the echo yielded a geometric distance of 6.2 kpc, making V838 Mon at maximum brighter than a CN\null. ILRTs have been discovered in several nearby galaxies, including M31 (1988), NGC 300 (2008 and 2010), and others. V838 Mon remained a luminous red supergiant throughout its outburst. Several years after eruption, its slowly expanding dusty photosphere ingested a B-type companion star, producing spectacular photometric and spectroscopic variability as the B star was engulfed. I organized a workshop on ILRTs, held at STScI in June 2011. A consensus emerged that there are two (at least) channels producing ILRTs: catastrophic mergers of contact binaries, and outbursts on massive stars of an uncertain nature, possibly electron-capture SNe. I propose to continue to monitor V838 Mon with the SMARTS 1.3m (photometry) and 1.5m (spectroscopy) telescopes. I also request TOO time on the same two telescopes to follow new ILRTs as they are discovered, which recently has been more than once a year.


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NOAO >   Observing Info >   Approved Programs >   2012A-0388

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