Kinematic Structure of Molecular Gas around High-mass Star YSO, Papillon Nebula, in N159 East in the Large Magellanic Cloud

TL;DR

This study uses ALMA observations to analyze the molecular gas structure around a high-mass YSO in the Papillon Nebula, revealing filament collisions as a key mechanism for high-mass star formation in the LMC.

Contribution

It provides detailed ALMA data showing filamentary cloud collisions associated with high-mass YSO formation in the LMC, supporting the collision-induced star formation model.

Findings

Filamentary clouds in N159E are ~1 pc wide and 5-10 pc long.

A high-mass YSO (~35 Msun) is at the intersection of three filaments.

Evidence of cloud collision triggering high-mass star formation.

Abstract

We present the ALMA Band 3 and Band 6 results of 12CO(2-1), 13$CO(2-1), H30alpha recombination line, free-free emission around 98 GHz, and the dust thermal emission around 230 GHz toward the N159 East Giant Molecular Cloud (N159E) in the Large Magellanic Cloud (LMC). LMC is the nearest active high-mass star forming face-on galaxy at a distance of 50 kpc and is the best target for studing high-mass star formation. ALMA observations show that N159E is the complex of filamentary clouds with the width and length of ~1 pc and 5 pc - 10 pc, respectively. The total molecular mass is 0.92 x 10^5 Msun from the 13CO(2-1) intensity. N159E harbors the well-known Papillon Nebula, a compact high-excitation HII region. We found that a YSO associated with the Papillon Nebula has the mass of 35 Msun and is located at the intersection of three filamentary clouds. It indicates that the formation of the high-mass YSO was induced by the collision of filamentary clouds. Fukui et al. 2015 reported a similar kinematic structure toward a YSO in the N159 West region which is another YSO that has the mass larger than 35 Msun in these two regions. This suggests that the collision of filamentary clouds is a primary mechanism of high-mass star formation. We found a small molecular hole around the YSO in Papillon Nebula with sub-pc scale. It is filled by free-free and H30alpha emission. Temperature of the molecular gas around the hole reaches ~ 80 K. It indicates that this YSO has just started the distruction of parental molecular cloud.