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Abstract 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 solar masses) star formation. Observations from the Yebes 40 m and IRAM 30 m telescopes detect for the first time in the 7 mm, 3 mm, and 2 mm 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 $3.1_{-0.6}^{+0.4}$, 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 $0.0115_{-0.0009}^{+0.0008}$, a factor of 10 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. 

ABSTRACT Cold ($$\sim$$10 K) and dense ($$\sim 10^{5}$$ cm$$^{-3}$$) cores of gas and dust within molecular clouds, known as starless and dynamically evolved pre-stellar cores, are the birthplaces of low-mass (M$$\le$$ few M$$_\odot$$) stars. As detections of interstellar complex organic molecules, or COMs, in starless cores has increased, abundance comparisons suggest that some COMs might be seeded early in the star formation process and inherited to later stages (i.e. protostellar discs and eventually comets). To date observations of COMs in starless cores have been limited, with most detections reported solely in the Taurus molecular cloud. It is therefore still a question whether different environments affect abundances. We have surveyed 35 starless and pre-stellar cores in the Perseus molecular cloud with the Arizona Radio Observatory (ARO) 12 m telescope detecting both methanol, CH$$_3$$OH, and acetaldehyde, CH$$_3$$CHO, in 100 per cent and 49 per cent of the sample, respectively. In the sub-sample of 15 cores where CH$$_3$$CHO was detected at $$\gt 3\sigma$$ ($$\sim$$18 mK) with the ARO 12 m, follow-up observations with the Yebes 40 m telescope were carried out. Detections of formic acid, t-HCOOH, ketene, H$$_2$$CCO, methyl cyanide, CH$$_3$$CN, vinyl cyanide, CH$$_2$$CHCN, methyl formate, HCOOCH$$_3$$, and dimethyl ether, CH$$_3$$OCH$$_3$$, are seen in at least 20 per cent of the cores. We discuss detection statistics, calculate column densities, and compare abundances across various stages of low-mass star formation. Our findings have more than doubled COM detection statistics in cold cores and show COMs are prevalent in the gas before star and planet formation in the Perseus molecular cloud. 

ABSTRACT Low-mass stars like our Sun begin their evolution within cold (10 K) and dense (∼105 cm−3) cores of gas and dust. The physical structure of starless cores is best probed by thermal emission of dust grains. We present a high-resolution dust continuum study of the starless cores in the B10 region of the Taurus Molecular Cloud. New observations at 1.2 and 2.0 mm (12 and 18 arcsec resolution) with the NIKA2 instrument on the IRAM 30m have probed the inner regions of 14 low-mass starless cores. We perform sophisticated 3D radiative transfer modelling for each of these cores through the radiative transfer framework pandora, which utilizes RADMC-3D. Model best-fits constrain each cores’ central density, density slope, aspect ratio, opacity, and interstellar radiation field strength. These ‘typical’ cores in B10 span central densities from 5 × 104 to 1 × 106 cm−3, with a mean value of 2.6 × 105 cm−3. We find the dust opacity laws assumed in the 3D modelling, as well as the estimates from Herschel, have dust emissivity indices, β’s, on the lower end of the distribution constrained directly from the NIKA2 maps, which averages to β = 2.01 ± 0.48. From our 3D density structures and archival NH3 data, we perform a self-consistent virial analysis to assess each core’s stability. Ignoring magnetic field contributions, we find nine out of the 14 cores (64  per cent) are either in virial equilibrium or are bound by gravity and external pressure. To push the bounded cores back to equilibrium, an effective magnetic field difference of only ∼15 $$\mu$$G is needed.