Anissa Pokorny-Yadav | Searcharxiv

arXiv2026

Inventories of Rich Carbon-Chain Chemistry in Prestellar and Starless Cores in the Perseus Molecular Cloud

Carbon-chain molecules serve as an important reservoir of reactive organic matter that will eventually be incorporated into protoplanetary disks, planets, and cometary material. Prestellar and starless cores are composed of cold (~ 10 K) and dense (~ 10$^5$ cm$^{-3}$) clumps of gas and dust within molecular clouds, and are nurseries for low-mass stars and planetary systems. Surveys of starless cores have focused on the study of complex organic molecules, COMs, whereas observations of carbon-chains in starless cores are limited. We analyze the carbon-chain inventories of 15 prestellar and starless cores in the Perseus Molecular Cloud. Using Yebes 40m single-dish observations, we detect CS, CCS, CCCS, HC$_3$N, DC$_3$N, and HC$_5$N in at least 10/15 cores and HC$_7$N in 4/15 cores. Our study also finds related isotopologues, where $^{13}$CS, C$^{34}$S, C$^{13}$CS, CC$^{34}$S, H$^{13}$CCCN, HC$^{13}$CCN, HCC$^{13}$CN, HC$^{13}$CCCCN, HCC$^{13}$CCCN, HCCC$^{13}$CCN, HCCCCC$^{15}$N, and DCCCCCN are detected. We report detection statistics, compare column density ratios with Taurus, Serpens, and protostar sources, examine DC$_3$N/HC$_3$N deuterium fractionation, and investigate the relative abundances and correlations between cyanopolyyne (HC$_n$N) and sulfur-bearing (C$_n$S) carbon-chains. The diverse suite of species detected reveals the richness of carbon-chain chemistry in Perseus and illustrates how local environmental conditions, such as density, temperature, and proximity to protostellar activity, shape each core's molecular inventory and relative evolutionary phase. Our findings provide a glimpse into the carbon-chain reservoir of starless and prestellar cores in Perseus, which may ultimately be inherited by emerging protoplanetary disks and later integrated into planetary systems and biologically relevant material.

astro-ph.GA↗

arXiv2025

First Detections of PN, PO, and PO+ toward a Shocked Low-mass Starless Core

Phosphorus is a key element that plays an essential role in biological processes important for living organisms on Earth. The origin and connection of phosphorus-bearing molecules to early Solar system objects and star-forming molecular clouds is therefore of great interest, yet there are limited observations throughout different stages of low-mass ($M < $ a few M$_\odot$) star formation. Observations from the Yebes 40 m and IRAM 30 m telescopes detect for the first time in the 7mm, 3mm, and 2mm bands multiple transitions of PN and PO, as well as a single transition of PO$^{+}$, toward a low-mass starless core. The presence of PN, PO and PO$^{+}$ is kinematically correlated with bright SiO(1-0) emission. Our results reveal not only that shocks are the main driver of releasing phosphorus from dust grains and into the gas-phase, but that the emission originates from gas not affiliated with the shock itself, but quiescent gas that has been shocked in the recent past. From radiative transfer calculations, the PO/PN abundance ratio is found to be $3.1^{+0.4}_{-0.6}$, consistent with other high-mass and low-mass star-forming regions. This first detection of PO$^{+}$ toward any low-mass star-forming region reveals a PO$^{+}$/PO ratio of $0.0115^{+0.0008}_{-0.0009}$, a factor of ten lower than previously determined from observations of a Galactic Center molecular cloud, suggesting its formation can occur under more standard Galactic cosmic-ray ionization rates. These results motivate the need for additional observations that can better disentangle the physical mechanisms and chemical drivers of this precursor of prebiotic chemistry.

astro-ph.GA↗