2024/09/19 by Arijit Manna, Manna, Arijit, Sabyasachi Pal +1
Physics and Astronomy · #Stellar, planetary, and galactic studies #Astrophysics and Star Formation Studies #Astronomy and Astrophysical Research
paper · pdf · doi:10.48550/arxiv.2409.12907
Phosphorus (P) is an important element for the chemical evolution of galaxies and many kinds of biochemical reactions. Phosphorus is one of the crucial chemical compounds in the formation of life on our planet. In an interstellar medium, phosphine (PH3) is a crucial biomolecule that plays a major role in understanding the chemistry of phosphorus-bearing molecules, particularly phosphorus nitride (PN) and phosphorus monoxide (PO), in the gas phase or interstellar grains. We present the first confirmed detection of phosphine (PH3) in the asymptotic giant branch (AGB) carbon-rich star IRC+10216 using the Atacama Large Millimeter/Submillimeter Array (ALMA) band 6. We detect the J = 10-00 rotational transition line of PH3 with a signal-to-noise ratio (SNR) of ≥3.5σ. This is the first confirmed detection of phosphine (PH3) in the ISM. Based on LTE spectral modelling, the column density of PH3 is (3.15±0.20)×1015 cm-2 at an excitation temperature of 52±5 K. The fractional abundance of PH3 with respect to H2 is (8.29±1.37)×10-8. We also discuss the possible formation pathways of PH3 and we claim that PH3 may be created via the hydrogenation of PH2 on the grain surface of IRC+10216.