Circumstellar Disks in the Outer Galaxy: the Star-Forming Region NGC 1893

Abstract

It is still debated whether star formation process depends on environment. In particular it is yet unclear whether star formation in the outer Galaxy, where the environmental conditions are, theoretically, less conducive, occurs in the same way as in the inner Galaxy. We investigate the population of NGC1893, a young cluster ~3-4 Myr in the outer part of the Galaxy (galactic radius >11 Kpc), to explore the effects of environmental conditions on star forming regions. We present infrared observations acquired using the IRAC camera onboard the Spitzer Space Telescope and analyze the color-color diagrams to establish the membership of stars with excesses. We also merge this information with that obtained from Chandra ACIS-I observations, to identify the Class III population. We find that the cluster is very rich, with 242 PMS Classical T-Tauri stars and 7 Class 0/I stars. We identify 110 Class III candidate cluster members in the ACIS-I field of view. We estimate a disk fraction for NGC1893 of about 67%, similar to fractions calculated for nearby star forming regions of the same age. Although environmental conditions are unfavorable, star formation can clearly be very successful in the outer Galaxy, allowing creation of a very rich cluster like NGC1893.

10 pages,7 figures,4 tables

References in corpus (2)

• A Survey for New Members of Taurus with the Spitzer Space Telescope
• Star formation in young star cluster NGC 1893

Cited by in corpus (5)

• Age Gradients in the Stellar Populations of Massive Star Forming Regions Based on a New Stellar Chronometer
• Extreme infrared variables from UKIDSS - II. an end-of-survey catalogue of eruptive YSOs and unusual stars
• Sejong Open Cluster Survey (SOS). III. The Young Open Cluster NGC 1893 in the H II Region W8
• Sejong Open Cluster Survey (SOS) - IV. The Young Open Clusters NGC 1624 and NGC 1931
• Deep V and I CCD photometry of young star cluster NGC 1893 with the 3.6m DOT