JpGU-AGU Joint Meeting 2017

Presentation information

[JJ] Poster

P (Space and Planetary Sciences) » P-PS Planetary Sciences

[P-PS09] [JJ] Origin and evolution of materials in space

Mon. May 22, 2017 10:45 AM - 12:15 PM Poster Hall (International Exhibition Hall HALL7)

convener:Shogo Tachibana(Department of Natural History Scieces, Hokkaido University), Hitoshi Miura(Graduate School of Natural Sciences, Department of Information and Basic Science, Nagoya City University), Takafumi Ootsubo(Graduate School of Arts and Sciences, University of Tokyo), Hideko Nomura(Department of Earth and Planetary Sciences, Tokyo Institute of Technology)

[PPS09-P07] Mid-infrared observations of the dust-forming classical nova V2676 Oph with Subaru/COMICS

Hideyo Kawakita1, *Takafumi Ootsubo2, Akira Arai1, Shinnaka Yoshiharu3, Masayoshi Nagashima (1.Koyama Astronomical Observatory, Kyoto Sangyo University, 2.Graduate School of Arts and Sciences, University of Tokyo, 3.National Astronomical Observatory of Japan)

Keywords:nova, dust, infrared

A dust-forming nova V2676 Oph (discovered in Mar 2012) was the first nova to provide evidence of both C2 and CN molecules during its near-maximum phase and evidence of CO molecules during its early decline phase (Nagashima et al. 2014). The derived carbon- and nitrogen-isotopic ratios in the nova (Kawakita et al. 2015) are consistent with that the nova explosion was hosted by a CO-rich white dwarf (WD) star. To confirm a type of the hosting WD (CO-rich or ONe-rich), we performed the mid-infrared imaging and low-resolution spectroscopic observations of V2676 Oph with COMICS mounted on the Subaru telescope in June 2013 and May 2014 (482 days and 782 days respectively after its discovery). No clear [Ne II] emission line at 12.8 micron was observed. Based on the absence of [Ne II] emission, the WD hosting V2676 Oph is considered a CO-rich WD. Both types of dust grain, carbon-rich and oxygen- rich, were detected on both dates, although this nova is considered as a Carbon-rich (C/O > 1) based on the presence of C2 observed earlier. The 11.4 micron unidentified infrared emission was also detected on these dates. Non-equilibrium processes are likely to be responsible for the grain formation in the nova.