Protostars and Planets VI, Heidelberg, July 15-20, 2013
Poster 1H020
The Herschel Orion Protostar Survey: Constraining Protostellar Models with Near- to Far-Infrared Observations
Furlan, Elise (NOAO, IPAC/Caltech)
Ali, Babar (NHSC/IPAC/Caltech)
Fischer, Will (University of Toledo)
Tobin, John (NRAO)
Stutz, Amy (MPIA)
Megeath, Tom (University of Toledo)
Allen, Lori (NOAO)
HOPS team, ()
Abstract:
During the protostellar stage of star formation, a young star
is surrounded by a large infalling envelope of dust and gas;
the material falls onto a circumstellar disk and is eventually
accreted by the central star. The dust in the disk and envelope
emits prominently at mid- to far-infrared wavelengths; at 10
micron, absorption by small silicate grains typically causes
a broad absorption feature. By modeling the near- to far-IR
spectral energy distributions (SEDs) of protostars, properties
of their disks and envelopes can be derived.
As part of the Herschel Orion Protostar Survey (HOPS; PI: S. T.
Megeath), we have observed a large sample of protostars in the
Orion star-forming complex at 70 and 160 micron with the PACS
instrument on the Herschel Space Observatory. For most objects,
we also have photometry in the near-IR (2MASS), mid-IR (Spitzer/
IRAC and MIPS), at 100 micron (PACS data from the Gould Belt
Survey), sub-mm (APEX/SABOCA and LABOCA), and mid-infrared spectra
(Spitzer/IRS). For the interpretation of the SEDs, we have
constructed a large grid of protostellar models using a Monte
Carlo radiative transfer code.
Here we present our SED fitting techniques to determine the
best-fit model for each object. We show the importance of
including IRS spectra with appropriate weights, in addition to
the constraints provided by the PACS measurements, which probe
the peak of the SED. The 10 micron silicate absorption feature
and the mid- to far-IR SED slope provide key constraints for the
inclination angle of the object and its envelope density, with
a deep absorption feature and steep SED slope for the most
embedded and highly inclined objects. We show a few examples
that illustrate our SED fitting method and present some
preliminary results from our fits.
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