A dataset provided by the European Space Agency

Name OT2_ewirst01_2
Title Determining the Ice Desorption Mechanism in Cold Molecular Clouds


DOI https://doi.org/10.5270/esa-7psepc7
Author wirstrom, e.
Description Interstellar ices are readily formed from accretion of atoms and molecules
onto cold dust grains, and in dense cores the gas would be depleted in all
heavy molecules were it not for the operation of some non-thermal desorption

Methanol molecules are only formed efficiently from hydrogenation of CO
molecules accreted onto grains, but is still widely observed in cold dense
clouds. This attests to the operation of desorption processes not related to
the heating up of the gas from a nearby star. Proposed mechanisms for
injecting the ice mantle molecules into the gas-phase includes both continuous
processes, such as cosmic-ray impacts, photodesorption, or ejection upon
formation, and more transient ones such as clump-clump collisions, and
effects of embedded protostars influencing the chemistry through shocks or
dissipation of magnetohydrodynamic (MHD) waves. The presence of distinct peaks
of methanol emission at positions significantly offset from protostars,
however, implies that the desorption process is indeed transient, and likely
to also disrupt a major part of the ice mantles. This would lead to very high
water abundances at these peaks, clearly distinguishable from what is expected
from photodesorption or steady-state gas-phase chemistry.

In order to constrain the active ice desorption mechanisms in cold molecular
clouds, we thus propose to use HIFI to observe the ground state transition of ortho water
at three different methanol peaks: two at different distances from the Class I
protostar Barnard 5 IRS1, and one in L1512, a region free from protostellar
Publication Cold Water Vapor in the Barnard 5 Molecular Cloud . Wirström E. S. et al. . The Astrophysical Journal Letters, Volume 788, Issue 2, article id. L32, 5 pp. (2014). . 788 . 10.1088\/2041-8205\/788\/2\/L32 . 2014ApJ...788L..32W ,
Instrument HIFI_HifiPoint_pos
Temporal Coverage 2012-08-11T06:48:41Z/2012-08-29T19:45:10Z
Version SPG v14.1.0
Mission Description Herschel was launched on 14 May 2009! It is the fourth 'cornerstone' mission in the ESA science programme. With a 3.5 m Cassegrain telescope it is the largest space telescope ever launched. It is performing photometry and spectroscopy in approximately the 55-671 µm range, bridging the gap between earlier infrared space missions and groundbased facilities.
Creator Contact https://support.cosmos.esa.int/h®erschel/
Date Published 2013-02-28T19:41:50Z
Publisher And Registrant European Space Agency
Credit Guidelines European Space Agency, wirstrom, e., 2013, OT2_ewirst01_2, SPG v14.1.0, European Space Agency, https://doi.org/10.5270/esa-7psepc7