CENSUS OF SELF-OBSCURED MASSIVE STARS IN NEARBY GALAXIES WITH SPITZER: IMPLICATIONS FOR UNDERSTANDING THE PROGENITORS OF SN 2008S-LIKE TRANSIENTS

Journal Article · Tue Jun 01 04:00:00 EDT 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/715/2/1094· OSTI ID:21450918

Khan, Rubab; Stanek, K Z; Kochanek, C S; Thompson, Todd A; Beacom, J F ^[1]

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1. Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 (United States)

A new link in the causal mapping between massive stars and potentially fatal explosive transients opened with the 2008 discovery of the dust-obscured progenitors of the luminous outbursts in NGC 6946 and NGC 300. Here, we carry out a systematic mid-IR photometric search for massive, luminous, and self-obscured stars in four nearby galaxies: M33, NGC 300, M81, and NGC 6946. For detection, we use only the 3.6 {mu}m and 4.5 {mu}m IRAC bands, as these can still be used for multi-epoch Spitzer surveys of nearby galaxies ({approx}<10 Mpc). We combine familiar point-spread function and aperture photometry with an innovative application of image subtraction to catalog the self-obscured massive stars in these galaxies. In particular, we verify that stars analogous to the progenitors of the NGC 6946 (SN 2008S) and NGC 300 transients are truly rare in all four galaxies: their number may be as low as {approx}1 per galaxy at any given moment. This result empirically supports the idea that the dust-enshrouded phase is a very short lived phenomenon in the lives of many massive stars and that these objects constitute a natural extension of the asymptotic giant branch sequence. We also provide mid-IR catalogs of sources in NGC 300, M81, and NGC 6946.

• OSTI ID: 21450918
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 715; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
BINARY STARS
DUSTS
ERUPTIVE VARIABLE STARS
GALAXIES
IMAGES
PHOTOMETRY
STARS
SUPERNOVAE
VARIABLE STARS