Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published March 10, 2019 | Submitted + Published
Journal Article Open

Supernova 2017eaw: Molecule and Dust Formation from Infrared Observations

Abstract

We present infrared (IR) photometry and spectroscopy of the Type II-P SN 2017eaw and its progenitor in the nearby galaxy NGC 6946. Progenitor observations in the Ks band in four epochs from 1 yr to 1 day before the explosion reveal no significant variability in the progenitor star greater than 6% that lasts longer than 200 days. SN 2017eaw is a typical SN II-P with near-IR and mid-IR photometric evolution similar to those of SNe 2002hh and 2004et, other normal SNe II-P in the same galaxy. Spectroscopic monitoring during the plateau phase reveals a possible high-velocity He I 1.083 μm absorption line, indicative of a shock interaction with the circumstellar medium. Spectra between 389 and 480 days postexplosion reveal a strong CO first overtone emission at 389 days, with a line profile matching that of SN 1987A from the same epoch, indicating ~10^(−3) M⊙ of CO at 1800 K. From the 389 days epoch until the most recent observation at 566 days, the first overtone feature fades while the 4.5 μm excess, likely from the CO fundamental band, remains. This behavior indicates that the CO has not been destroyed, but that the gas has cooled enough that the levels responsible for first overtone emissions are no longer populated. Finally, the evolution of Spitzer 3.6 μm photometry shows evidence for dust formation in SN 2017eaw, with a dust mass of 10^(−6) or 10^(−4) M⊙ assuming carbonaceous or silicate grains, respectively.

Additional Information

© 2019 The American Astronomical Society. Received 2019 January 28; revised 2019 February 16; accepted 2019 February 18; published 2019 March 13. We thank Jim Fuller and Luc Dessart for helpful discussions and input on the paper draft. We also thank the anonymous referee for reviewing the article. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. Some of the data presented herein were obtained at Palomar Observatory, which is operated by a collaboration between California Institute of Technology, Jet Propulsion Laboratory, Yale University, and National Astronomical Observatories of China. This work is based in part on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech. This research has made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. R.D.G. was supported by NASA and the United States Air Force. Facilities: Hale (WIRC, TripleSpec) - , Spitzer - Spitzer Space Telescope satellite, Keck (MOSFIRE, NIRES) - . Software: astropy (Astropy Collaboration et al. 2013; Price-Whelan et al. 2018), spextool (Cushing et al. 2004), xtellcor (Vacca et al. 2003), MOSFIRE data reduction pipeline (McLean et al. 2012), MOCASSIN (v.2.02.72 Ercolano et al. 2003, 2005, 2008), Matplotlib (Hunter 2007).

Attached Files

Published - Tinyanont_2019_ApJ_873_127.pdf

Submitted - 1901.01940.pdf

Files

Tinyanont_2019_ApJ_873_127.pdf
Files (5.5 MB)
Name Size Download all
md5:b91a5f2ea094010ca7aaf5fc0e9b34d7
3.8 MB Preview Download
md5:e6fed84c2d39c767f5745513a2365802
1.7 MB Preview Download

Additional details

Created:
August 19, 2023
Modified:
October 20, 2023