J/ApJ/703/1964 Spectra of three nearby star-forming regions (Furlan+, 2009)
Disk evolution in the three nearby star-forming regions of Taurus, Chamaeleon, and Ophiuchus. Furlan E., Watson D.M., McClure M.K., Manoj P., Espaillat C., D'Alessio P., Calvet N., Kim K.H., Sargent B.A., Forrest W.J., Hartmann L. <Astrophys. J., 703, 1964-1983 (2009)> =2009ApJ...703.1964F
ADC_Keywords: Molecular clouds ; Spectra, infrared ; YSOs Keywords: circumstellar matter - infrared: stars - stars: formation - stars: pre-main sequence Abstract: We analyze samples of Spitzer Infrared Spectrograph spectra of T Tauri stars in the Ophiuchus, Taurus, and Chamaeleon I star-forming regions, whose median ages lie in the <1-2Myr range. The median mid-infrared spectra of objects in these three regions are similar in shape, suggesting, on average, similar disk structures. When normalized to the same stellar luminosity, the medians follow each other closely, implying comparable mid-infrared excess emission from the circumstellar disks. We use the spectral index between 13 and 31um and the equivalent width of the 10um silicate emission feature to identify objects whose disk configuration departs from that of a continuous, optically thick accretion disk. Based on their medians and fraction of evolved disks, T Tauri stars in Taurus and Chamaeleon I are very alike. Description: Our Taurus, Chamaeleon I, and Ophiuchus targets were observed as part of an IRS guaranteed-time program during IRS campaigns 3, 4, 12, 19, 20, 21, 22, 23, 29, and 30, which were scheduled from 2004 February to 2006 April. The objects (table 5) were originally selected from infrared catalogs of YSOs in these regions that were compiled before the launch of the Spitzer Space Telescope in 2003. All targets were observed with either the two low-resolution IRS modules (Short-Low (SL) and Long-Low (LL), 5.2-14um and 14-38um, respectively) or the SL module and the two high-resolution modules (Short-High (SH) and Long-High (LH), 10-19um and 19-37um, respectively). In this way, we obtained the full mid-infrared spectrum from 5 to 40um for each target. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 45 63 Properties of the targets in the Ophiuchus core region table2.dat 45 85 Properties of the targets in the Taurus region table3.dat 45 69 Properties of the targets in the Chamaeleon I region table4.dat 45 15 Properties of the targets in the Ophiuchus off-core region table5.dat 46 233 Target names and coordinates table6a.dat 40 310 Ophiuchus core median (H normalization) table6b.dat 40 310 Chamaeleon I median (H normalization) table6c.dat 40 310 Taurus median (H normalization)
See also: II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003) II/156 : IRAS Faint Source Catalog, |b| > 10, Version 2.0 (Moshir+ 1989) V/73 : Emission-Line Stars of the Orion Population (Herbig+ 1988) J/A+A/519/A34 : YSOs in DROXO (Deep rho Oph XMM obs.) (Pillitteri+, 2010) J/A+A/515/A75 : Low-mass population in ρ Oph cloud (Alves de Oliveira+, 2010) J/ApJ/692/973 : Protostars in Perseus, Serpens and Ophiuchus (Enoch+, 2009) J/PASJ/60/209 : Faint companions around YSOs in TMC (Itoh+, 2008) J/ApJ/683/822 : Star formation in Ophiuchus and Perseus II. (Jorgensen+, 2008) J/ApJS/173/104 : Stellar population in Chamaeleon I (Luhman, 2007) J/A+A/452/245 : Near-IR photometry of PMS stars in rho Oph (Natta+, 2006) J/A+A/460/695 : Search for Associations Containing Young stars (Torres+, 2006) J/AJ/130/1733 : Optical spectroscopy of ρ Oph stars (Wilking+, 2005) J/AJ/126/2971 : UBVRI photometry of 131 Herbig Ae/Be (Vieira+, 2003) J/A+A/372/173 : ISOCAM observations of the rho Ophiuchi cloud (Bontemps+, 2001) J/A+A/357/219 : ISOCAM observations in Cha I. (Persi+, 2000) J/ApJS/112/109 : Rho Oph Near-IR Positions and Photometry (Barsony+, 1997) J/ApJS/101/117 : UBVRIJHKLMNQ photometry in Taurus-Auriga (Kenyon+ 1995) Byte-by-byte Description of file: table1.dat table2.dat table3.dat table4.dat
Bytes Format Units Label Explanations
1- 20 A20 --- Name Target name 22- 26 A5 --- SpT Adopted MK spectral type (1) 28- 31 F4.1 --- Av ? Optical extinction A_V_ (assuming R_V_=3.1) (2) 33- 37 F5.2 um EW ? The 10um equivalent width in um 39- 43 F5.2 --- n13-31 ? The 13-31um spectral index (n13-31) 45 A1 --- Med [x]? x: the object was used in the median calculation
Note (1): Spectral types were taken from references below: * In table 1: from Brandner & Zinnecker (1997A&A...321..220B); Luhman & Rieke (1999ApJ...525..440L); Wilking et al. (2005, Cat. J/AJ/130/1733); Natta et al. (2006, Cat. J/A+A/452/245); McClure et al. (2010ApJS..188...75M); * In table 2: from Kenyon et al. (1990AJ.....99..869K); Hartigan et al. (1994ApJ...427..961H); Strom & Strom (1994ApJ...424..237S); Kenyon & Hartmann (1995, Cat. J/ApJS/101/117); Torres et al. (1995AJ....109.2146T); Kenyon et al. (1998AJ....115.2491K); Briceno et al. (1998AJ....115.2074B); Luhman (2000ApJ...544.1044L); White & Ghez (2001ApJ...556..265W); Hartigan & Kenyon (2003ApJ...583..334H); White & Basri (2003ApJ...582.1109W); White & Hillenbrand (2004ApJ...616..998W); Calvet et al. (2004AJ....128.1294C); Furlan et al. (2006ApJS..165..568F). * In table 3: spectral type and, where available, extinction information were taken from Luhman (2004ApJ...602..816L) and Gomez & Mardones (2003AJ....125.2134G). For objects without published or with uncertain extinction values, the optical extinction AV was derived using the observed optical/near-infrared colors and intrinsic colors based on the spectral type or a typical CTTS excess (see the text for details). * In table 4: spectral types were taken from Herbig & Bell (1988, Cat. V/73); Chen et al. (1995ApJ...445..377C); Preibisch et al. (1998, Cat. J/A+A/333/619); Vieira et al. (2003, Cat. J/AJ/126/2971); Torres et al. (2006, Cat. J/A+A/460/695); McClure et al. (2010ApJS..188...75M). Note (2): Uncertainties in AV are detailing below: * In table 1: uncertainties in AV, ranging from 1% to 30% of the AV value (McClure et al. 2010ApJS..188...75M), account for ∼25% of the error bars of EW(10um) and n13-31. * In table 2: uncertainties in AV, assumed to be 0.3mag (Kenyon & Hartmann 1995, Cat. J/ApJS/101/117), account for ∼15% and 1% of the error bars of EW(10um) and n13-31, respectively. * In table 3: uncertainties in AV, assumed to be 0.46mag (Luhman 2007, Cat. J/ApJS/173/104), account for ∼10% and 2% of the error bars of EW(10um) and n13-31, respectively. * In table 4: uncertainties in AV, which are typically 0.3mag (McClure et al. 2010ApJS..188...75M), account for ∼10% and 1% of the error bars of EW(10um) and n13-31, respectively.
Byte-by-byte Description of file: table5.dat
Bytes Format Units Label Explanations
1- 20 A20 --- Name Target name 23- 24 I2 h RAh Hour of Right Ascension (J2000) (3) 26- 27 I2 min RAm Minute of Right Ascension (J2000) 29- 33 F5.2 s RAs Second of Right Ascension (J2000) 36 A1 --- DE- Sign of the Declination (J2000) (3) 37- 38 I2 deg DEd Degree of Declination (J2000) 40- 41 I2 arcmin DEm Arcminute of Declination (J2000) 43- 46 F4.1 arcsec DEs Arcsecond of Declination (J2000)
Note (3): Objects with 4h<RA<5.5h are in Taurus, objects with 10h<RA<12h are in Chamaeleon I, objects with 16h<RA<17h are in Ophiuchus.
Byte-by-byte Description of file: table6[abc].dat
Bytes Format Units Label Explanations
1- 4 F4.1 um lambda Wavelength in micron 8- 16 E9.3 mW/m2 nuFnu Median flux density νF_ν_ (1) 20- 28 E9.3 mW/m2 e_nuFnu Lower quartile in nuFnu (1) 32- 40 E9.3 mW/m2 E_nuFnu Upper quartile in nuFnu (1)
Note (1): These are the median, lower quartile, and upper quartile for the Ophiuchus core (L1688), Chamaeleon I and Taurus calculated using the IRS spectra of 28, 28 and 52 Class II objects, respectively, with K5-M2 spectral types, normalized at their 2MASS H-band fluxes.
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 02-Nov-2011
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