The First Detections of the Key Prebiotic Molecule PO in Star-forming Regions

Journal
Date Issued
2016
Author(s)
Rivilla, V. M.
•
•
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Vasyunin, A.
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Caselli, P.
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Martín-Pintado, J.
•
DOI
Abstract
Phosphorus is a crucial element in biochemistry, in particular the P-O bond, which is key in the formation of the backbone of deoxyribonucleic acid. So far, PO has only been detected toward the envelope of evolved stars, but never toward star-forming regions. We report the first detection of PO toward two massive star-forming regions, W51 e1/e2 and W3(OH), using data from the IRAM 30 m telescope. PN has also been detected toward the two regions. The abundance ratio PO/PN is 1.8 and 3 for W51 and W3(OH), respectively. Our chemical model indicates that the two molecules are chemically related and are formed via gas-phase ion-molecule and neutral-neutral reactions during cold collapse. The molecules freeze out onto grains at the end of the collapse and desorb during the warm-up phase once the temperature reaches ∼35 K. Similar abundances of the two species are expected during a period of ∼5 × 104 yr at the early stages of the warm-up phase, when the temperature is in the range 35-90 K. The observed molecular abundances of 10-10 are predicted by the model if a relatively high initial abundance of 5 × 10-9 of depleted phosphorus is assumed.
Volume
826
Issue
2
Start page
161
Uri
Url
Issn Identifier
0004-637X
Ads BibCode
2016ApJ...826..161R
Rights
open.access
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