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Observing Iron Stars with Spitzer
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Only two so-called Iron stars exist: XX Oph and AS 325. XX Oph was first
observed in 1924 by Merrill. He noted strong, doubly ionized iron
emission lines were present in the spectra, thus the name iron star.
AS325 was noted to be a similar type object by Howell and Bopp (1982).
Further observations of both stars have led to the development of a model
(Cool et al., 2005) for both stars which explains the optical emission
lines and that the stars consist of two separate stars, possibly in a
binary. The current model has each Iron Star composed of a Be star and a
late type (supergiant) companion separated by 1-2 thousand AU. The the
interaction of the Be wind with the mass loss from the red star and the
dust/gas remnant cocoon surrounding them both. We plan to use Spitzer to
observe the dust environment in the star AS325.
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Lead Teachers:
Beth Thomas (co-lead)
East Middle School,
Great Falls, MT
Lauren Chapple (co-lead)
Traverse City East Junior High School,
Traverse City, MI
Participating Teachers:
Steve Rapp
Linwood Holton Governor's School,
Abingdon, VA
Theresa Roelofsen
Bassick High School, Bridgeport, CT
Cynthia Weehler
Luther Burbank High School, San Antonio, TX
Support Scientists:
Dr. Steve Howell
National Optical Astronomical Observatory, Tucson, AZ
Dr. Don Hoard
Spitzer Science Center, Pasadena, CA
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Proposal News
Work Summary:
November 2005
October 2005
September 2005
August 2005
April 2005 - pdf file
March 2005 - pdf file
Proposal - pdf file
AOR - pdf file
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Proposed Observation Time
IRS Staring
We will obtain Spitzer IRS high resolution spectra of AS 325.
We will use the low resolution capabilities of the IRS on Spitzer to obtain mid-infrared spectral energy distribution (SED).
The IRS_Peakup with the moderate option and a blue filter will not only insure accuracy but will also provide an image of the target.
We will utilize the Hi_Short, Hi_Long, Lo_Short5, Lo_Short7 features of the IRS with varying exposures and cycles based on a flux density of 60.4 mJy.
Total exposure time, including overhead, for this proposal is 1966.7 seconds or 32 minutes.
Visibility:
April 4, 2005 - May 12 2005
September 2005
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