Contents of: VI/111/./abstract/MBARLOW_VEGA.abs

The following document lists the file abstract/MBARLOW_VEGA.abs from catalogue VI/111.
A plain copy of the file (without headers/trailers) may be downloaded.


SCIENTIFIC ABSTRACT
One of the major discoveries made by IRAS was finding the presence of a
far-infrared excess around the standard star Vega (Alpha Lyrae) and around a
number of other similar main sequence stars. The infrared excess has been
interpreted as due to a disk of dust particles left over from the formation of
such stars. The LWS will be used to study the dust disks around a number of
these stars, in particular obtaining grating spectra to look for the 44 micron
and 62 micron ice bands in emission from the cool disks. Fabry-Perot scans will
also be obtained at the wavelengths of a number of ionic fine structure lines in
the case of beta Pictoris, the only star in the sample for which the disk has
been imaged and studied spectroscopically at non-infrared wavelengths.
A LaTex file containing fuller details of this proposal is available
from 

OBSERVATION SUMMARY
Grating spectra are needed to look for dust features in the disks, and to
investigate fully which lines are present. beta Pic will be observed with the FP
as well, since optical and UV observations have already indicated the presence
of emitting gas around this system. The FP observations will enhance the
detectability of weaker lines seen against the dust continuum, as well as
providing velocity (and thus dynamical) information about gas in the disk.
8.1 hours of LWS Guaranteed (spacecraft) time are allocated to this programme.
If stars in the Orion-hole are observable (i.e. a Spring launch), 324.5 minutes
will be used for full LWS grating scans of eight  stars and 121.2 minutes will
be used for full SWS fast grating scans of four stars. 51.1 minutes will be used
for LWS FP scans of the spectrum of beta Pictoris at the wavelengths of six fine
structure lines, these are:  CII (157.7um), NII (121.9um), OI (63.2, 145.5um),
FeIII (51.7um) and FeII (51.3um).
If stars in the Sagittarius-hole are observable (i.e. an Autumn launch),
446.2 minutes will be used for full LWS grating scans of eleven stars and 30.3
minutes will be used for a full SWS fast grating scans of one star
(complementary SWS scans of the remaining stars are being obtained by the SWS
consortium). The Priority 1 LWS Guaranteed spacecraft time allocated to this
programme is 3.21 hours if the Orion-hole is observable, or 3.38 hours if the
Sgr-hole is observable.