Letter to the Editor

Near infrared coronagraph images of IRC +10216

Faint structures at 1–5″ from the central star

¹ University of Hertfordshire, College Lane, Hatfield, Herts AL10 9AB, UK
² National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
³ Subaru Telescope, 650 North A'ohoku place, Hilo, HI 96720, USA
⁴ University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
⁵ Nagoya University Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
⁶ University of Manchester, Jodrell Bank Radio obesrvatory, Macclesfield, Cheshire SK11 9DL, UK

Corresponding author: K. Murakawa, murakawa@star.herts.ac.uk

Received: 19 October 2001
Accepted: 29 September 2002

Abstract

We present J, H and K band coronagraph images of the circumstellar envelope around IRC +10216 (CW Leo) obtained with a near infrared camera, CIAO and the 8.2 m Subaru telescope. A circular occulting mask of 2″ in diameter was used to block out the light from the bright central object. The images show 2 collimated radial structures to the NNW and WNW, 2 fan-like structures to the S and NE, respectively, and 3 arc-like structures at a radius of 4 to 5 arcsec from the stellar center. We compare this intermediate size-scale structure to that seen on larger and smaller scales and find evidence for a deviation from spherically symmetric outflow beginning ~150 years ago. Previous near infrared speckle imaging has revealed a complex clumpy structure on a scale of less than 200 mas, and it is likely that at least some of the radial features seen in our images could be due to shadowing by dust clumps close to the star.