CaltechAUTHORS
Published February 10, 2008 | Version Published
Journal Article Open

The environment of M85 optical transient 2006-1 : constraints on the progenitor age and mass

Creators

  • 1. ROR icon California Institute of Technology
  • 2. ROR icon Herzberg Institute of Astrophysics
  • 3. ROR icon Washington State University
  • 4. ROR icon European Southern Observatory
  • 5. ROR icon Galaxies, Etoiles, Physique et Instrumentation
  • 6. ROR icon Johns Hopkins University
  • 7. ROR icon University of California, Santa Cruz

Abstract

M85 Optical Transient 2006-1 (M85 OT 2006-1) is the most luminous member of the small family of V838 Mon-like objects, whose nature is still a mystery. This event took place in the Virgo Cluster of galaxies and peaked at an absolute magnitude of MI ≈ -13. Here we present Hubble Space Telescope images of M85 OT 2006-1 and its environment, taken before and after the eruption, along with a spectrum of the host galaxy at the transient location. We find that the progenitor of M85 OT 2006-1 was not associated with any star-forming region. The g- and z-band absolute magnitudes of the progenitor were fainter than about –4 and –6 mag, respectively. Therefore, we can set a lower limit of ~50 Myr on the age of the youngest stars at the location of the progenitor that corresponds to a mass of <7 M⊙. Previously published line indices suggest that M85 has a mean stellar age of 1.6 ± 0.3 Gyr. If this mean age is representative of the progenitor of M85 OT 2006-1, then we can further constrain its mass to be less than 2 M⊙. We compare the energetics and mass limit derived for the M85 OT 2006-1 progenitor with those expected from a simple model of violent stellar mergers. Combined with further modeling, these new clues may ultimately reveal the true nature of these puzzling events.

Additional Information

© 2008 The American Astronomical Society. Received 2007 July 12; accepted 2007 October 9. This work is supported in part by grants from NSF and NASA.

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Published - OFEapj08a.pdf

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Additional details

Identifiers

Eprint ID
13861
Resolver ID
CaltechAUTHORS:20090407-085637117

Funding

NSF
NASA

Dates

Created
2009-07-15
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Updated
2021-11-08
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Caltech groups
Division of Geological and Planetary Sciences (GPS)