• Kataza, Hirokazu
• Matsuhara, Hideo
• Nozawa, Takaya
• Asano, Kentaro
• Sakon, Itsuki
• Usui, Fumihiko
• Onaka, Takashi
• Kaneda, Hidehiro
• Ohsawa, Asano
• Nakagawa, Takao
• Fujiyoshi, Takuya
• Okamoto, Yoshiko
• Murakami, Hiroshi

Abstract

Recent AKARI/IRC observations of SN2008ax in NGC4490 on the day 98 has revealed the presence of near-infrared excess emission. This emission can be interpreted as the re-radiation from the pre-existing circumstellar amorphous carbon dust of a color temperature of 767±45 K and the mass of 1.2^{+0.4}_{-0.3} × 10^{-5} M_{☉} or silicate dust of 885±60 K and 6.8^{+2.5}_{-1.7}× 10^{-5} M_{☉}, which may have been formed in the mass loss wind from the OB/WR progenitor in an interacting binary system. In order to investigate the on-going dust formation by WR binary systems, the mid-infrared observations of the Galactic WR binary WR140 were carried out with Subaru/COMICS on 1st August 2009. 11.7μm image of WR140 has shown that the dust cloud formed during the previous periastron passage in 2001 has expanded up to 2.6'' away from the stellar core with an expansion velocity of 2.7±0.3 × 10^{3} km s^{-1}. The high-spatial resolution N-band spectrum of dust structures around WR140 was obtained for the first time and broad band features at ̃8.3 μm and ̃12.2 μm were detected. The possible carriers of these emission bands are discussed....

Topics

• amorphous
• Carbon