Discovery of Striking Difference of Molecular-Emission-Line Richness in the Potential Proto-Binary System NGC 2264 CMM3

TL;DR

This study uses ALMA to reveal a binary system in NGC 2264 CMM3, showing a stark contrast in molecular emission, with one component rich in complex molecules and the other deficient, indicating different evolutionary stages.

Contribution

First detailed interferometric survey of NGC 2264 CMM3 revealing a binary system with contrasting molecular emission properties.

Findings

CMM3 is a binary system with two continuum peaks, CMM3A and CMM3B.

CMM3A is rich in complex organic molecules, indicating a hot core.

CMM3B shows deficient molecular line emission despite similar continuum flux.

Abstract

We have conducted an interferometric line survey in the 0.8 mm band toward the young high-mass protostar candidate NGC 2264 CMM3 with ALMA. CMM3 is resolved into the two continuum peaks, CMM3A and CMM3B, at an angular separation of 0.9". Thus, CMM3 is found to be a binary system candidate. We have detected molecular outflows associated with CMM3A and CMM3B each, indicating active star formation. In addition to the two peaks, six faint continuum peaks are detected around CMM3A and CMM3B, most of which are thought to be evolved low-mass protostars. CMM3A is found to be rich in molecular line emission including complex organic molecules such as HCOOCH3 and CH3OCH3. The emission of complex organic molecules is distributed within a compact region around the continuum peak of CMM3A. Hence, CMM3A apparently harbors a hot core. On the other hand, CMM3B is deficient in molecular line emission, although its continuum flux is almost comparable to that of CMM3A. Possible origins of the striking difference between CMM3A and CMM3B are discussed.