Australia Telescope Compact Array observations of the OH star Roberts 22: Resolved images of hydroxyl emission

Citation
Kk. Dyer et al., Australia Telescope Compact Array observations of the OH star Roberts 22: Resolved images of hydroxyl emission, ASTRONOM J, 121(5), 2001, pp. 2743-2751
Citations number
15
Categorie Soggetti
Space Sciences
Journal title
ASTRONOMICAL JOURNAL
ISSN journal
00046256 → ACNP
Volume
121
Issue
5
Year of publication
2001
Pages
2743 - 2751
Database
ISI
SICI code
0004-6256(200105)121:5<2743:ATCAOO>2.0.ZU;2-Z
Abstract
We have imaged the unusual OH/IR object G284-0.8 (Roberts 22) in the OH tra nsitions at 1612, 1665, and 1667 MHz using the Australia Telescope Compact Array in Narrabri, NSW, Australia. The angular resolution of the OH images we present here is 6 " (12,000 AU at a distance of 2 kpc). We find OH emiss ion of extent 1."5 (2800 AU) located inside the optical bipolar flow region (size 8 ") discovered in the early eighties by Allen et al. and imaged rec ently by Sahai et al. with the Hubble Space Telescope. We present astrometr y of Roberts 22, providing registration of the OH and Hubble Space Telescop e images to within similar to0." 35. We describe the OH velocity field in R oberts 22 and discuss the kinematic properties of the source and its evolut ionary status.