Phosphorus-bearing molecules in the Galactic Center

TL;DR

This study reports the detection of phosphorus-bearing molecules PN and PO in the Galactic Center, suggesting their formation in shock-dominated regions and destruction in high-radiation environments, advancing understanding of phosphorus chemistry in space.

Contribution

It provides new observational data on P-bearing molecules in the Galactic Center and proposes formation and destruction mechanisms related to shock and radiation conditions.

Findings

PN detected in 5 of 7 sources, associated with shock chemistry.

PO detected only in one source, with a PO/PN ratio of ~1.5.

P-bearing molecules form in shocks and are destroyed by intense radiation.

Abstract

Phosphorus (P) is one of the essential elements for life due to its central role in biochemical processes. Recent searches have shown that P-bearing molecules (in particular PN and PO) are present in star-forming regions, although their formation routes remain poorly understood. In this Letter, we report observations of PN and PO towards seven molecular clouds located in the Galactic Center, which are characterized by different types of chemistry. PN is detected in five out of seven sources, whose chemistry is thought to be shock-dominated. The two sources with PN non-detections correspond to clouds exposed to intense UV/X-rays/cosmic-ray radiation. PO is detected only towards the cloud G+0.693$-$0.03, with a PO/PN abundance ratio of $\sim$1.5. We conclude that P-bearing molecules likely form in shocked gas as a result of dust grain sputtering, while are destroyed by intense UV/X-ray/cosmic ray radiation.