A Spitzer Search for Evolved Disks in Taurus


First Author:
Caer-Eve McCabe
Email: mccabe AT ipac.caltech.edu
SSC/Caltech
1200 E. California Blvd
Pasadena, CA 91125
Coauthors:
Padgett, Deborah, SSC/Caltech
Rebull, Luisa, SSC/Caltech
Hillenbrand, Lynne, Caltech
Noriega-Crespo, Alberto, SSC/Caltech
Carey, Sean, SSC/Caltech
Brooke, Tim, SSC/Caltech
Huard, Tracy, Maryland
Fukagawa, Misato, Nagoya
Hines, Dean, SSI
Terebey, Susan, CSULA
Stapelfeldt, Karl, JPL
Guedel, Manuel, PSI
Audard, Marc, Geneva
Monin, Jean-Louis, Grenoble
Guieu, Sylvain, SSC/Caltech
Knapp, Gillian, Princeton
Evans, Neal, UT Austin

Abstract

We report the initial results of a search for evolved disk candidates, objects with colors intermediate between those of stars and class II pre-main-sequence objects, in the 44 square degree region covered by the Taurus Spitzer Legacy survey. Two separate color criteria are applied: (1) an IRAC [3.6]-[4.5] vs. [5.8]-[8.0] search on objects with 2MASS Ks < 14.5 mag, and (2) a [3.6]-[8.0] vs. [3.6]-[24] search. Combined, these search criteria provide a sample of ~190 objects, including known T Tauri stars, brown dwarfs, galaxies, red giants, and previously unknown sources. All known extragalactic and non-pre-main-sequence objects were removed. Likely extragalactic contaminants were identified through investigation of the 2MASS, IRAC and MIPS color planes, along with a visual inspection of the SDSS and CFHT images. The resulting sample of nearly 2 dozen evolved disk candidates are shown, only two of which are previously known transition/evolved disks (V819 Tau, LkCa 15). One third of these candidates show strong evidence for the presence of an evolved disk around a young star - the remaining two thirds are complicated by uncertainties in either pre-main-sequence status, cloud membership, or multiplicity, each of which is discussed. Follow-up spectroscopy on the previously unknown objects in the Taurus field has begun; we present near-infrared Keck/NIRSPEC spectra of a new mid-M type star with a clear UV excess and evidence for an evolved disk.