High-resolution Study of the Outflow Activity and Chemical Environment of Chamaeleon-MMS1

Abstract

The earliest stages of low-mass star formation are unclear, with the first hydrostatic core (FHSC) as the transition stage between a prestellar and protostellar core. This work describes the local (∼4000 au) outflow activity associated with candidate FHSC Chamaeleon-MMS1 and its effect on the surrounding material to determine the evolutionary state of this young low-mass source. We observed Chamaeleon-MMS1 with the Atacama Large Millimeter/submillimeter Array at 220 GHz at high spatial (∼75 au) and spectral resolutions (0.1–0.3 km s ^−1 ). A low-energy outflow is detected, consisting of two components, a broad spectral feature (Δ v ∼ 8 km s ^−1 ) to the northeast and narrow spectral features (Δ v ∼ 1 km s ^−1 ) to both the northeast and southwest. The molecular tracers CS, formaldehyde (H _2 CO), and methanol (CH _3 OH) were used to analyze the effect of the outflows on the surrounding gas and determine its rotational temperature. The rotational temperature of H _2 CO is 40 K toward the continuum source with similarly low temperatures (10–75 K) toward clumps affected by the outflow. CH _3 OH is only detected toward gas clumps located away from the continuum source, where the methanol is expected to have been released by the energy of the outflow through ice sputtering. While molecular emission and high outflow speeds rule Cha-MMS1 out as an FHSC, its outflow is less energetic than those of other Class 0 objects and its physical properties are within the range covered by other low-luminosity protostars. The inferred gas temperatures toward the continuum source are also relatively low, indicating that Cha-MMS1 is one of the youngest known sources.

Keywords

• Stellar jets
• Astrochemistry
• Star formation
• Low mass stars
• Young stellar objects
• CO line emission