Until a decade ago, the only anion observed to play a prominent role in astrophysics was H–
. The bound–free transitions in H–dominate the visible opacity in stars with photospheric …

The introduction of chemistry into astronomy is relatively recent and can be dated back to
about half a century ago, when molecules were discovered in space. In the 1930s it was …

To date, 204 individual molecular species, comprised of 16 different elements, have been
detected in the interstellar and circumstellar medium by astronomical observations. These …

To date, 241 individual molecular species, composed of 19 different elements, have been
detected in the interstellar and circumstellar medium by astronomical observations. These …

We present the fifth release of the UMIST Database for Astrochemistry (UDfA). The new
reaction network contains 6173 gas-phase reactions, involving 467 species, 47 of which are …

We review the gas-phase chemistry in extraterrestrial space that is driven by reactions with
atomic and molecular ions. Ions are ubiquitous in space and are potentially responsible for …

We present new observations of molecular anions with the Yebes 40 m and IRAM 30 m
telescopes toward the cold, dense clouds TMC-1 CP, Lupus-1A, L1527, L483, L1495B, and …

The Electron Spectrometer (ELS), one of the sensors making up the Cassini Plasma
Spectrometer (CAPS) revealed the existence of numerous negative ions in Titan's upper …

We report the detection in the envelope of the C-rich star IRC+ 10216 of four series of lines
with harmonically related frequencies: B1389, B1390, B1394, and B1401. The four series …

1.1. Interstellar Clouds and Interstellar Chemistry A space between stars is not completely a
vacuum, but is filled up with interstellar gas, whose average number density of H nuclei in all …