56 citations · 165 across the 12 of their papers we have counts for
12 papers
First mapping of prebiotic molecule CH2NH in a pre-stellar core
Yuxin Lin, Silvia Spezzano, Olli Sipilä +2
We present the first spatially resolved map of methanimine CH2NH in the prestellar core L1544 using the IRAM 30m telescope. The 2-1 line at 127 GHz was mapped with…
High deuteration of methanol in L1544
S. Spezzano, W. Riedel, P. Caselli +7
Isotopic fractionation is a very powerful tool to follow the evolution of material from one stage to the next in the star-formation process. Pre-stellar cores exhibit some of the h…
New Orbital Constraints for YSES 1 b and HR 2562 B from High-Precision Astrometry and Planetary Radial Velocities
Jonathan Roberts, William Thompson, Jason J. Wang +20
We present new VLTI/GRAVITY astrometry and updated orbit fits for the directly imaged companions YSES 1 b and HR 2562 B, substellar objects straddling the planet-brown dwarf bounda…
Hunting pre-stellar cores with APEX: overview
P. Caselli, S. Spezzano, E. Redaelli +8
[Abridged] Pre-stellar cores are centrally concentrated starless cores on the verge of star formation and they represent the initial conditions for star and planet forma…
The Effect of Weak Cosmic Ray Heating Events on the Desorption of
O. Sipilä, K. Silsbee, N. Carbajal +2
The typical amount of molecular hydrogen () in interstellar ices is not known, but significant freeze-out of on dust grains is not expected. However, chemica…
Measurements and simulations of rate coefficients for the deuterated forms of the H2 + + H2 and H3 + + H2 reactive systems at low temperature
Miguel Jiménez-Redondo, Olli Sipilä, Pavol Jusko +1
The rate coefficients of various isotopic variations of the H2+ + H2 and H3+ + H2 reactions in the 10-250 K temperature range were measured using a cryogenic 22 pole radio frequenc…
A low cosmic-ray ionisation rate in the prestellar core Ophiuchus/H-MM1. Mapping of the molecular ions ortho-H2D+, N2H+, and DCO+
Jorma Harju, Charlotte Vastel, Olli Sipilae +5
(abridged) We have mapped the prestellar core H-MM1 in Ophiuchus in rotational lines of ortho-H2D+ (oH2D+), N2H+, and DCO+ at the wavelength 0.8 mm with the Large APEX sub-Millimet…
Effect of grain size distribution and size-dependent grain heating on molecular abundances in starless and pre-stellar cores
O. Sipilä, B. Zhao, P. Caselli
We present a new gas-grain chemical model to constrain the effect of grain size distribution on molecular abundances in starless and pre-stellar cores. We introduce grain-size depe…
Carbon isotopic fractionation in molecular clouds
L. Colzi, O. Sipilä, E. Roueff +2
C-fractionation has been studied from a theoretical point of view with different models of time-dependent chemistry, including both isotope-selective photodissociation and low-temp…
Gas and dust temperature in pre-stellar cores revisited: New limits on cosmic-ray ionization rate
Alexei V. Ivlev, Kedron Silsbee, Olli Sipilä +1
We develop a self-consistent model for the equilibrium gas temperature and size-dependent dust temperature in cold, dense pre-stellar cores, assuming an arbitrary power-law size di…
Deuterated forms of H and their importance in astrochemistry
Paola Caselli, Olli Sipilä, Jorma Harju
At the low temperatures (10 K) and high densities (100,000 H molecules per cc) of molecular cloud cores and protostellar envelopes, a large amount of molecular spec…
A study of the -/- ratio in low-mass star forming regions
J. Chantzos, S. Spezzano, P. Caselli +4
We use the deuteration of - to probe the physical parameters of starless and protostellar cores, related to their evolutionary states, and compare it to the…