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J/ApJ/733/50 Mid-IR photometric monitoring of the ONC (Morales-Calderon+, 2011)

YSOVAR: the first sensitive, wide-area, mid-infrared photometric monitoring of the Orion Nebula Cluster. Morales-Calderon M., Stauffer J.R., Hillenbrand L.A., Gutermuth R., Song I., Rebull L.M., Plavchan P., Carpenter J.M., Whitney B.A., Covey K., de Oliveira C.A., Winston E., McCaughrean M.J., Bouvier J., Guieu S., Vrba F.J., Holtzman J., Marchis F., Hora J.L., Wasserman L.H., Terebey S., Megeath T., Guinan E., Forbrich J., Huelamo N., Riviere-Marichalar P., Barrado D., Stapelfeldt K., Hernandez J., Allen L.E., Ardila D.R., Bayo A., Favata F., James D., Werner M., Wood K. <Astrophys. J., 733, 50 (2011)> =2011ApJ...733...50M
ADC_Keywords: Clusters, open ; Photometry, infrared ; YSOs ; Stars, variable Keywords: circumstellar matter - stars: variables: general - open clusters and associations: individual (Orion) - stars: pre-main sequence - stars: protostars Abstract: We present initial results from time-series imaging at infrared wavelengths of 0.9deg2 in the Orion Nebula Cluster (ONC). During Fall 2009 we obtained 81 epochs of Spitzer 3.6 and 4.5um data over 40 consecutive days. We extracted light curves with ∼3% photometric accuracy for ∼2000 ONC members ranging from several solar masses down to well below the hydrogen-burning mass limit. For many of the stars, we also have time-series photometry obtained at optical (Ic) and/or near-infrared (JKs) wavelengths. Our data set can be mined to determine stellar rotation periods, identify new pre-main-sequence eclipsing binaries, search for new substellar Orion members, and help better determine the frequency of circumstellar disks as a function of stellar mass in the ONC. Our primary focus is the unique ability of 3.6 and 4.5um variability information to improve our understanding of inner disk processes and structure in the Class I and II young stellar objects (YSOs). In this paper, we provide a brief overview of the YSOVAR Orion data obtained in Fall 2009 and highlight our light curves for AA-Tau analogs -YSOs with narrow dips in flux, most probably due to disk density structures passing through our line of sight. Detailed follow-up observations are needed in order to better quantify the nature of the obscuring bodies and what this implies for the structure of the inner disks of YSOs. Description: Our GO6 Exploration Science program YSOVAR (Young Stellar Object Variability) provides the first large-scale survey of mid-IR photometric variability of YSOs. In Fall 2009, we used ∼250hr of warm Spitzer observing time to monitor ∼0.9deg2 of the ONC at 3.6 and 4.5um. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file stars.dat 46 2067 The ONC stars sample (table added by CDS with coordinates from table 2 in the published version) table2.dat 58 351324 Time series at the [3.6] and [4.5] IRAC bands for the ONC stars
See also: J/AJ/142/60 : Palomar Transient Factory Orion Project (Van Eyken+, 2011) J/AJ/139/950 : JHKs photometry in ONC (Robberto+, 2010) J/A+A/515/A13 : Very low mass objects in ONC (Rodriguez-Ledesma+, 2010) J/ApJ/676/1109 : Velocities of stars in the ONC (Furesz+, 2008) J/ApJ/671/605 : NGC 2264 and ONC PMS stars in the infrared (Cieza+, 2007) J/ApJS/160/353 : Membership of the Orion nebula population (Getman+, 2005) : YSOVAR project website Byte-by-byte Description of file: stars.dat
Bytes Format Units Label Explanations
1- 5 A5 --- --- [ISOY_] 6- 24 A19 --- ISOY Object identification ( 26- 35 F10.7 deg RAdeg [83.5/84.1] Right Ascension in decimal degrees (J2000) 37- 46 F10.7 deg DEdeg [-6.1/-4.6] Declination in decimal degrees (J2000)
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 5 A5 --- --- [ISOY_] 6- 24 A19 --- ISOY Object identification ( 26- 39 F14.8 d MJD [55127.4/55166.7] Modified Julian date of the observation 41- 45 A5 --- Band [IRAC1/IRAC2] Spitzer/IRAC band (IRAC1=3.6um or IRAC2=4.5um) 47- 52 F6.3 mag mag [5.073/16.645] Observed magnitude in Band 54- 58 F5.3 mag e_mag Error in mag
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 06-Nov-2012
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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