Phosphorus in the interstellar medium: the missing prebiotic element

Phosphorus (P) is a crucial element for prebiotic chemistry and for the
development of life in the Universe. It is one of the key components of deoxyri-
bonucleic acid (DNA), phospholipids (the structural components of all cellular
membranes) and the adenosine triphosphate (ATP) molecule, from which all
forms of life assume energy. The Chemistry Nobel Prize Sir Alexander Todd remarked the astrobiological importance of P when he said: ’Where there’s life,
there’s phosphorus’. For these reasons, the study of interstellar phosphorus is
generating increasing interest in the last years. It is mandatory its study in
star-forming regions, where stars, planets (and eventually life) are expected to
arise. However, our knowledge about P in the interstellar medium is still very
poor. For this, our group started several observational and theoretical projects
to study P-bearing species in star-forming regions. In my talk I will present the
the first detections of P-O - key chemical bond to build-up the DNA double
helix - towards two star-forming regions, and multiple detections of PN towards
a large sample of massive dense cores. The observed molecular abundances
indicates that P is significantly more abundant in star-forming regions than
previously thought. I will also show the results of recent ALMA and IRAM 30m
telescope observations of selected massive cores in the Galactic Disk and several
clouds in the Galactic Center, which suggest that shocks may have a key role
to sputtering P from grain mantles and to explain the observed abundances of
P-bearing molecules in the gas-phase. All these findings are helping us to attain
a much better understanding about the unknown chemistry of P in space.