First Submillimeter Lights from Dome A: Tracing the Carbon Cycle in the Feedback of Massive Stars

TL;DR

This paper reports the first successful submillimeter observations from Dome A, revealing detailed carbon phase distributions in star-forming regions and providing insights into how massive stars influence their surrounding interstellar medium.

Contribution

It presents the first submillimeter CO and [CI] mapping observations from Dome A, enabling a complete characterization of carbon phases in star-forming regions.

Findings

Elevated C0/CO ratios in high-extinction regions.

Deep radiation penetration influences carbon chemistry.

Milestone achievement for Dome A submillimeter astronomy.

Abstract

The cycling of carbon between its ionized, atomic, and molecular phases shapes the chemical compositions and physical conditions of the interstellar medium (ISM). However, ground-based studies of the full carbon cycle have been limited by atmospheric absorption. Dome~A, the most promising site for submillimeter astronomy, has long resisted successful submillimeter astronomical observations. Using the 60~cm Antarctic Terahertz Explorer, we present the first successful CO ($4-3$) and [CI] ($^3P_1 - ^3P_0$) mapping observations of two archetypal triggered massive star-formation regions at Dome~A. These data, together with archival [CII], provide the first complete characterization of all three carbon phases in these environments. We find elevated C$^{0}$/CO abundance ratios in high-extinction regions, plausibly driven by deep penetration of intense radiation fields from massive stars into a clumpy ISM. These findings mark a major milestone for submillimeter astronomy at Dome~A and offer valuable insights into the impact of massive star feedback on the surrounding ISM.