Gas and Dust in CrA

Abstract

Coronae Austrinae is one of the few star formation areas lying well away from the galactic plane (l = 360°, b = −17°) and is visible predominantly from the Southern Hemisphere.

L1642 — A Dust Cloud in a Cometary Globule?

“…(See for example elementary texts such as Lamb, 1945. ) The appearance of the densest dust region, L1642, on the edge of this region would then be consistent with the dust-gas instability associations observed in CrA (Taylor et al 1982) in which similar relative locations appear for a number of dark cloud components on the HI morphology. The reasons for this disposition have not yet been understood but clearly are related to the mass flow of the various cloud components once the hydrodynamic instability phase sets in.…”

The Corona Australis Dark Cloud

“…It is evident that these results may be interpreted in terms of extensive H 2 formation, varying from a minimum of 10°/o to greater than 90%. For low A,' these observations suggest N(HI) = 3 x lO^M.crrr (H) in agreement with Taylor et al (1981) which is nearly an order of magnitude less than that in (9). The reason for the relatively low yV(HI)A4" ratio is unclear, but not uncommon in dense clouds.…”

“…We have mapped the Corona Australia cometary globule complex in the hydrogen 21-cm line. Preliminary results are reported in Llewellyn et al (1981) and Taylor et al (1981). This paper considers the particular region centred on a(1950) = 18*59 m 30', 5(1950) = -37°20' where we mapped at < 5' arc spacing (beamwidth 15.7' arc) over approximately one square degree.…”

“…The Corona Australis cometary globule is a large southern object known to be a region of slow star formation. We have mapped the complex in the 21cm hydrogen line and preliminary results are reported in Llewellyn et al (1981) and Taylor et al (1981). The most extensive A, map of the region is given by Rossano (1978) and is based on star counts.…”