HIGHLIGHTS: this week in A&A
Volume 462-3 (February II 2007)
The widest ultracool binary
“The widest ultracool binary”, by J.A. Caballero A&A 462, p. L61
The leading scenario for the formation of brown dwarfs and very low-mass stars is that they are ejected from
their formation region before they have a chance to accrete more mass, and it predicts that pairs of very
low mass stars must be tight (<20 AU) to survive this ejection. This letter presents the serendipitous detection of
a very low mass binary separated by 1800 AU. Together with a few other pairs separated by up
to 300 AU it demonstrates that some very low mass must form through another channel.
CO radiative cooling in the solar atmosphere
“Carbon monoxide in the solar atmosphere.II. Radiative cooling by CO
lines”, by S. Wedemeyer-Böhm and M. Steffen A&A 462, p. L31
The paper studies the role of carbon monoxide as a possible cooling
agent for the thermal structure of the lower solar atmosphere in internetwork regions and concludes that the structure and dynamics of the
outer solar atmosphere are determined primarily by shock waves and
magnetic fields.
SiO jet in the HH212 protostar
“A highly-collimated SiO jet in the HH212 protostellar outflow”,
by C. Codella et al. A&A 462, p. L53
The paper discusses new, high spatial resolution SiO
observations of the protostellar outflow source HH212 and finds
that SiO is a powerful tracer of molecular jets in protostellar
sources, in particular of their obscured innermost regions.
In section 12. Atomic, molecular, and nuclear data
“Effects of CO2 on H2O band profiles and band strengths in mixed H2O:CO2 ices”, by K.I. Öberg et al.
A&A 462, p. 1187
This paper reports on an experimental study of the effects of mixing CO2 with H2O ice on the H2O band strengths and
profiles that shows that the H2O band is affected in observable ways by CO2. This allows one to accurately determine
the contribution of water ice to the 6 µm absorption feature observed in embedded young stellar objects.
© Astronomy & Astrophysics 2007