000002763 001__ 2763
000002763 005__ 20160701171710.0
000002763 037__ $$aASTROimport-920
000002763 100__ $$aSargent, B.
000002763 245__ $$aThe First Light Curves of the Dustiest, Most Extreme Asymptotic Giant Branch Stars in the LMC and SMC
000002763 260__ $$c2012
000002763 520__ $$aAsymptotic giant branch (AGB) variable stars are, together with supernovae, the main sources of enrichment of the interstellar medium (ISM) in processed material, particularly carbon, nitrogen and heavy s-process elements. The dustiest, extreme AGB stars contribute the largest enrichment per star. We propose to measure the first light curves for 25 and 5 of the dustiest, most extreme AGB variable stars in the bar regions of Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC), respectively, using the warm Spitzer mission's IRAC 3.6 and 4.5 micron imaging for monthly imaging measurements. Though we know they are variable based on dual-epoch observations from the Spitzer Surveying the Agents of Galaxy Evolution (SAGE) surveys of the LMC and SMC, the periods of these extreme AGB stars have NOT been measured before because they are too faint in the optical and near-infrared to have been captured in the ground based synoptic surveys such as MACHO, OGLE and IRSF. Only Spitzer will be able to measure the light curve of this key phase of the AGB: the dustiest and indeed final stage of the AGB. Without this information, our developing picture of AGB evolution is decidedly incomplete. The observations we propose will test the validity of AGB evolution models, and, thus, their predictions of the return of mass and nucleosynthetic products to the ISM. A value-added component to this study is that we will obtain variability information on other AGB stars that lie within the fields of view of our observations. 
000002763 700__ $$a Meixner, M.
000002763 700__ $$a Riebel, D.
000002763 700__ $$a Vijh, U.
000002763 700__ $$a Boyer, M.
000002763 700__ $$a Cook, K.
000002763 700__ $$a Groenewegen, M.
000002763 700__ $$a Whitelock, P.
000002763 700__ $$a Ita, Y.
000002763 700__ $$a Hora, J.
000002763 700__ $$a Feast, M.
000002763 700__ $$a Kemper, C.
000002763 700__ $$a Marengo, M.
000002763 700__ $$a Matsuura, M.
000002763 700__ $$a Otsuka, M.
000002763 700__ $$a Srinivasan, S.
000002763 773__ $$c90219$$pSpitzer Proposal$$y2012
000002763 85642 $$ahttp://esoads.eso.org/abs/2012sptz.prop90219S
000002763 905__ $$apublished in
000002763 980__ $$aNONREF