title: Massive-star supernovae as major dust factories.
abstract: We present late-time optical and mid-infrared observations of the Type II supernova 2003gd in the galaxy NGC 628. Mid-infrared excesses consistent with cooling dust in the ejecta are observed 499 to 678 days after outburst and are accompanied by increasing optical extinction and growing asymmetries in the emission-line profiles. Radiative-transfer models show that up to 0.02 solar masses of dust has formed within the ejecta, beginning as early as 250 days after outburst. These observations show that dust formation in supernova ejecta can be efficient and that massive-star supernovae could have been major dust producers throughout the history of the universe.
authors.affiliation: Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA. sugerman@stsci.edu
authors.forename: Ben E K
authors.initials: BE
authors.lastname: Sugerman
authors.forename: Barbara
authors.initials: B
authors.lastname: Ercolano
authors.forename: M J
authors.initials: MJ
authors.lastname: Barlow
authors.forename: A G G M
authors.initials: AG
authors.lastname: Tielens
authors.forename: Geoffrey C
authors.initials: GC
authors.lastname: Clayton
authors.forename: Albert A
authors.initials: AA
authors.lastname: Zijlstra
authors.forename: Margaret
authors.initials: M
authors.lastname: Meixner
authors.forename: Angela
authors.initials: A
authors.lastname: Speck
authors.forename: Tim M
authors.initials: TM
authors.lastname: Gledhill
authors.forename: Nino
authors.initials: N
authors.lastname: Panagia
authors.forename: Martin
authors.initials: M
authors.lastname: Cohen
authors.forename: Karl D
authors.initials: KD
authors.lastname: Gordon
authors.forename: Martin
authors.initials: M
authors.lastname: Meyer
authors.forename: Joanna
authors.initials: J
authors.lastname: Fabbri
authors.forename: Janet E
authors.initials: JE
authors.lastname: Bowey
authors.forename: Douglas L
authors.initials: DL
authors.lastname: Welch
authors.forename: Michael W
authors.initials: MW
authors.lastname: Regan
authors.forename: Robert C
authors.initials: RC
authors.lastname: Kennicutt