RG lunch talk
30 May 2008, 12:30pm, M340

Insights into the VeLLO source L1521F IRS using 160 micron data from
the Taurus Spitzer Legacy Survey

Dr. Susan Terebey
CSULA

The interest in very low-luminosity embedded sources is to understand
where they fit into the evolutionary scheme of low-mass star-formation.
Using data from the Taurus Spitzer Legacy Survey, we analyze the 160
micron far-infrared emission near L1521F to investigate the cloud-core
environment around the previously identified VeLLO source.

In a 1x2 degree (2.5 x 5.0 pc) region centered on L1521F, the MIPS 160
um image shows both extended emission from the Taurus cloud as well as
emission from multiple cold cores. We derive kappa_160 = 0.23 cm^2/g
for the opacity of the gas-dust mixture, which is similar to
theoretical values in dense cores and much larger the value for the
diffuse ISM. The 160 um image also shows features that do not appear in
the IRAS 100 um image. From the data we can identify six regions as
cold cores, i.e. colder than 14.2 K, all of which have counterparts in
extinction maps or C18O maps.

We determine the effect of L1521F IRS on its natal core and find that
there is no evidence for dust heating at 160 or 100 um by the embedded
source. This means the observed long wavelength SED is dominated by
externally heated cloud emission at 100 um and longer wavelengths.
Comparison of L1521F IRS with theoretical models for the very early
phases of star formation suggest it is most consistent with the early
second collapse phase. However, the low source luminosity suggests a
timescale that is nearer to 10^5 yr than to 10^4 yr for the class 0
lifetime.