1Dept. of Astronomy, The Ohio State University, 140
W. 18th Ave., Columbus, OH 43210; khan, kstanek, email@example.com
2Center for Cosmology and AstroParticle Physics,
The Ohio State University, 191 W. Woodruff Ave., Columbus, OH 43210
Khan et al. 2013
Understanding the late-stage evolution of the most massive stars such as
is challenging because no true
Car have been clearly identified in the Milky Way or other galaxies.
In Khan et al. (2013)
, we utilized
IRAC images of
Mpc) galaxies to search for such analogs,
candidates with flat or red mid-IR spectral energy
distributions. Here, in PaperII,
we present our characterization of these
candidates using multi-wavelength data from the optical through the far-IR.
Our search detected no true analogs of
Car, which implies an eruption rate that
is a fraction
of the ccSN rate. This is
roughly consistent with each
outbursts in its lifetime.
However, we do identify a significant population of 18 lower luminosity
dusty stars. Stars enter this phase at a
rate that is fraction
of the ccSN rate,
and this is consistent
an obscured phase at most lasting a few thousand years
once or twice.
These phases constitute a negligible
fraction of post-main sequence lifetimes of massive stars, which implies
that these events are likely to be associated with special
periods in the evolution of the stars.
The mass of the obscuring material is of order
, and we simply do not find
enough heavily obscured stars for theses phases to represent more
than a modest fraction (
of the total mass lost by these stars.
In the long term, the sources that we identified
will be prime candidates for detailed physical analysis with JWST
stars: evolution, mass-loss, winds, outflows
-- stars: individual: Eta Carinae
-- galaxies: individual (M33, M81, NGC247, NGC300, NGC2403, NGC6822, NGC7793)
Finding Car Analogs in Nearby Galaxies Using Spitzer:
II. Identification of An Emerging Class of Extragalactic Self-Obscured Stars
C. S. Kochanek1,2,
K. Z. Stanek1,2,