ALMA and ROSINA detections of phosphorus-bearing molecules: the interstellar thread between star-forming regions and comets

Abstract

To understand how phosphorus (P)-bearing molecules are formed in star-forming regions, we have analysed the Atacama Large Millimeter/Submillimeter Array (ALMA) observations of PN and PO towards the massive star-forming region AFGL 5142, combined with a new analysis of the data of the comet 67P/Churyumov–Gerasimenko taken with the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) instrument onboard Rosetta. The ALMA maps show that the emission of PN and PO arises from several spots associated with low-velocity gas with narrow linewidths in the cavity walls of a bipolar outflow. PO is more abundant than PN in most of the spots, with the PO/PN ratio increasing as a function of the distance to the protostar. Our data favour a formation scenario in which shocks sputter phosphorus from the surface of dust grains, and gas-phase photochemistry induced by UV photons from the protostar allows efficient formation of the two species in the cavity walls. Our analysis of the ROSINA data has revealed that PO is the main carrier of P in the comet, with PO/PN > 10. Since comets may have delivered a significant amount of prebiotic material to the early Earth, this finding suggests that PO could contribute significantly to the phosphorus reservoir during the dawn of our planet. There is evidence that PO was already in the cometary ices prior to the birth of the Sun, so the chemical budget of the comet might be inherited from the natal environment of the Solar system, which is thought to be a stellar cluster including also massive stars.

Evolutionary study of complex organic molecules in high-mass star-forming regions

“…4) are different: pre-stellar cores, shock-dominated regions (protostellar shock and GC clouds), thermal-dominated regions (cores in low-to high-mass star-forming regions), and comets (whose chemical composition is thought to be presolar, see e.g. Rivilla et al 2020). This seems to reveal a rather universal chemistry for COMs, mainly developed at the cold earliest stages of star formation and then essentially preserved through the evolution, being only marginally altered by the evolving physical conditions.…”

The Leiden Atomic and Molecular Database (LAMDA): Current Status, Recent Updates, and Future Plans

“…• PH 3 as a key species in interstellar phosphorus chemistry [175,176] which also has application to Jupiter and exoplanet atmospheres [177]. Its structure resembles that of NH 3 , but the barrier to inversion (umbrella-mode vibration) is so much higher in PH 3 that the inversion splitting is unmeasurably small in the ground state and thus does not lead to any inversion transitions [178].…”

Ab Initio Study of Fine and Hyperfine Interactions in Triplet POH

“…For example, it has been proposed that meteorites [ 4 ] and comets [ 5 ] might have provided significant amounts of P, contained in minerals, such as schreibersite, or in simple molecular species, respectively. To date, only two P-bearing molecules have been identified in the interstellar medium (ISM), i.e., the gas of the molecular clouds that forms new stars and planets [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]: phosphorus nitride (PN) and phosphorus oxide (PO). To attain a better understanding of the phosphorous chemistry in the ISM and to ascertain what are its main carriers in space, the search for new P-bearing species is needed.…”