JCMT/SCUBA-2 Continuum Observations of Pre-protostellar Evolution

SCOPE: SCUBA-2 Continuum Observations of Pre-protostellar Evolution - Survey Description and Compact Source Catalogue

We present the first release of the data and compact-source catalogue for the JCMT Large Program SCUBA-2 Continuum Observations of Pre-protostellar Evolution (SCOPE). SCOPE consists of 850-um continuum observations of 1235 Planck Galactic Cold Clumps (PGCCs) made with the Submillimetre Common-User Bolometer Array 2 on the James Clerk Maxwell Telescope. These data are at an angular resolution of 14.4 arcsec, significantly improving upon the 353-GHz resolution of Planck at 5 arcmin, and allowing for a catalogue of 3528 compact sources in 558 PGCCs.

http://arxiv.org/abs/1902.10180

Methylamine and other N-bearing species in NGC 6334I MM1-3

Methylamine and other simple N-bearing species in the hot cores NGC 6334I MM1-3

In the search for the building blocks of life, nitrogen-bearing molecules are of particular interest since nitrogen-containing bonds are essential for the linking of amino acids and ultimately the formation of larger biological structures. The elusive molecule methylamine (CH3NH2) is thought to be a key pre-biotic species but has so far only been securely detected in the giant molecular cloud Sgr B2. We identify CH3NH2 and other simple nitrogen-bearing species towards three hot cores in NGC 6334I. Column density ratios are derived in order to investigate the relevance of the individual species as precursors of biotic molecules. 

http://arxiv.org/abs/1902.07060

Prebiotic relevance of interstellar ices

Interstellar ices: a possible scenario for symmetry breaking of extraterrestrial chiral organic molecules of prebiotic interest

In the laboratory, the photo-and thermochemical evolution of ices, made of simple molecules of astrophysical relevance, always leads to the formation of semi-refractory water-soluble organic residues. Targeted searches for specific molecules do reveal the notable presence of two families of important molecular ''bricks of life'': amino acids, key molecules in metabolism, and sugars, including ribose, the backbone of RNA molecules which support the genetic information in all living entities.

http://arxiv.org/abs/1902.04575

New brown dwarf candidates from Gaia DR2

New ultra-cool and brown dwarf candidates in Gaia DR2

Context. The second Gaia data release (Gaia DR2) contains high precision positions, parallaxes and proper motions for 1.3 billion sources. The resulting Hertzsprung-Russell diagram reveals fine structures all over the mass range. Aims. This paper aims to investigate the content of Gaia DR2 at the low-mass end and to characterize ultra-cool and brown dwarfs.

https://arxiv.org/abs/1809.08244

Carbon and oxygen in metal-poor halo stars

Carbon and oxygen are key tracers of the Galactic chemical evolution; in particular, a reported upturn in [C/O] towards decreasing [O/H] in metal-poor halo stars could be a signature of nucleosynthesis by massive Population III stars. We reanalyse carbon, oxygen, and iron abundances in thirty-nine metal-poor turn-off stars.

https://arxiv.org/abs/1901.03592