Corona Australis

We have recently performed a membership analysis based on Gaia-DR2 data over a field of 128 deg2 around the dark clouds of the region and identified 313 high-probability members.

Our new census of the Corona-Australis population covers the magnitude range from G > 5 mag to G < 20 mag, and includes stars with masses ranging from 0.02 to 5 solar masses. We report 262 stars which had never been classified as members before, and we increase the number of stars in this region by a factor of about five.

In particular, we discovered a more dispersed “off-cloud” population of stars in the north of the molecular clouds that is twice as numerous as the “on-cloud” population of stars which is located mostly in the densest cores of the region and contains most of the classical members identified in the past, as illustrated in Figure 1. The two populations exhibit slightly distinct properties, but they are very close to each other and part of the same star-forming complex. Our study also returned a new distance determination of 149.4 ± 0.4 pc for the Corona-Australis region that exceeds previous estimates by about 20pc. Altogether, this shows that the Corona-Australis region hosts one of the richest association of T Tauri stars of the Solar neighbourhood making it a promising target for many studies related to star and planet formation.

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