J/ApJS/186/111 Spitzer observations of Taurus members (Luhman+, 2010)
The disk population of the Taurus star-forming region.
Luhman K.L., Allen P.R., Espaillat C., Hartmann L., Calvet N.
<Astrophys. J. Suppl. Ser., 186, 111-174 (2010)>
=2010ApJS..186..111L 2010ApJS..186..111L (SIMBAD/NED BibCode)
ADC_Keywords: YSOs ; Photometry, infrared ; Spectral types
Keywords: accretion, accretion disks; brown dwarfs; protoplanetary disks;
stars: formation; stars: low-mass; stars: pre-main sequence
Abstract:
We have analyzed nearly all images of the Taurus star-forming region
at 3.6, 4.5, 5.8, 8.0, and 24µm that were obtained during the
cryogenic mission of the Spitzer Space Telescope (46deg2) and have
measured photometry for all known members of the region that are
within these data, corresponding to 348 sources, or 99% of the known
stellar population. By combining these measurements with previous
observations with the Spitzer Infrared Spectrograph and other
facilities, we have classified the members of Taurus according to
whether they show evidence of circumstellar disks and envelopes
(classes I, II, and III). Through these classifications, we find that
the disk fraction in Taurus, N(II)/N(II+III), is ∼75% for solar-mass
stars and declines to ∼45% for low-mass stars and brown dwarfs
(0.01-0.3M☉).
Through an analysis of multiple epochs of Spitzer photometry that are
available for ∼200 Taurus members, we find that stars with disks
exhibit significantly greater mid-infrared (mid-IR) variability than
diskless stars, which agrees with the results of similar variability
measurements for a smaller sample of stars in Chamaeleon I. The
variability fraction for stars with disks is higher in Taurus than in
Chamaeleon I, indicating that the IR variability of disks decreases
with age. Finally, we have used our data in Taurus to refine the
observational criteria for primordial, evolved, and transitional
disks. The ratio of the number of evolved and transitional disks to
the number of primordial disks in Taurus is 15/98 for spectral types
of K5-M5, indicating a timescale of 0.15xτprimordial∼0.45Myr for
the clearing of the inner regions of optically thick disks.
Description:
For our census of the disk population in Taurus, we use images at 3.6,
4.5, 5.8, and 8.0um obtained with Spitzer's Infrared Array Camera
(IRAC) and images at 24um obtained with the Multiband Imaging
Photometer for Spitzer (MIPS). The cameras produced images with
FWHM=1.6"-1.9" from 3.6 to 8.0um and FWHM=5.9" at 24um.
The available data were obtained through Guaranteed Time Observations
for PID = 6, 36, 37 (G. Fazio), 53 (G. Rieke), 94 (C. Lawrence), 30540
(G. Fazio, J. Houck), and 40302 (J. Houck), Director's Discretionary
Time for PID = 462 (L. Rebull), Legacy programs for PID = 139, 173 (N.
Evans), and 30816 (D. Padgett), and General Observer programs for PID
= 3584 (D. Padgett), 20302 (P. Andre), 20386 (P. Myers), 20762 (J.
Swift), 30384 (T. Bourke), 40844 (C. McCabe), and 50584 (D. Padgett).
The IRAC and MIPS observations were performed through 180 and 137
Astronomical Observation Requests (AORs), respectively.
The characteristics of the resulting images are summarized in Tables 1
and 2.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 97 523 IRAC observing log
table2.dat 73 221 MIPS 24um observing log
table4.dat 106 657 IRAC photometry for members of Taurus
table5.dat 106 27 IRAC photometry for members of Taurus with
extended emission
table6.dat 65 566 MIPS 24um photometry for members of Taurus
table7.dat 107 352 Spectral slopes for members of Taurus
--------------------------------------------------------------------------------
See also:
VII/244 : Atlas and Catalog of Dark Clouds (Dobashi+, 2005)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
J/ApJS/216/26 : T Tauri in Taurus-Auriga with GALEX (Gomez de Castro+, 2015)
J/ApJ/805/57 : Atmosphere parameters for PMS & BDs (Tottle+, 2015)
J/ApJ/745/119 : Close companions to young stars. I. ChaI + Tau (Nguyen+, 2012)
J/ApJS/196/4 : New young star candidates in Taurus-Auriga (Rebull+, 2011)
J/ApJS/186/259 : Taurus Spitzer survey: new candidate members (Rebull+, 2010)
J/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)
J/ApJS/181/321 : Properties of Spitzer c2d dark clouds (Evans+, 2009)
J/ApJS/176/457 : Taurus dark cloud background star catalog (Shenoy+, 2008)
J/ApJ/689/1295 : Lithium test implications for BDs (Kirkpatrick+, 2008)
J/ApJ/675/1375 : IRAC/MIPS photometry in Cha I (Luhman+, 2008)
J/PASP/119/994 : MIPS 24um calibrators (Engelbracht+, 2007)
J/A+A/468/353 : XMM-Newton Extended Survey of Taurus (Guedel+, 2007)
J/AJ/133/439 : Luminosity function of M7-L8 ultracool dwarfs (Cruz+, 2007)
J/AJ/132/2665 : QUEST2 BRI photometry of Taurus-Auriga PMS (Slesnick+, 2006)
J/ApJ/647/1180 : Infrared photometry of Taurus SFR (Luhman+, 2006)
J/ApJ/645/676 : Spatial distribution of brown dwarfs in Taurus (Luhman+, 2006)
J/A+A/446/485 : New very low-mass members in Taurus (Guieu+, 2006)
J/AJ/129/2294 : RVs of weak-lines T Tauri stars (Massarotti+, 2005)
J/ApJ/620/1010 : Spitzer 24µm photometry of A dwarfs (Rieke+, 2005)
J/ApJ/578/914 : Low-mass stars in Taurus (Hartmann, 2002)
J/A+A/337/403 : Low-mass stars evolutionary models (Baraffe+ 1998)
J/A+A/312/439 : New T Tauri stars in Taurus-Auriga (Wichmann+, 1996)
J/ApJS/101/117 : UBVRIJHKLMNQ photometry in Taurus-Auriga (Kenyon+ 1995)
http://sha.ipac.caltech.edu/applications/Spitzer/SHA/ : Spitzer Heritage
Archive
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 I8 --- AOR [3653120/26476800] Spitzer AOR number
10- 14 I5 --- PID [6/50584] Spitzer program ID
16- 26 A11 "Y/M/D" Date UT date of the observation
28- 29 I2 h RAh [4/5] 3.6/5.8 center hour of right ascension (J2000)
31- 32 I2 min RAm 3.6/5.8 center minute of right ascension (J2000)
34- 37 F4.1 s RAs 3.6/5.8 center second of right ascension (J2000)
39 A1 --- DE- [+] 3.6/5.8 center sign of declination (J2000)
40- 41 I2 deg DEd [15/31] 3.6/5.8 center degree of declination (J2000)
43- 44 I2 arcmin DEm 3.6/5.8 center arcminute of declination (J2000)
46- 47 I2 arcsec DEs 3.6/5.8 center arcsecond of declination (J2000)
49- 50 I2 h RA8h [4/5] 4.5/8.0 center hour of right ascension (J2000)
52- 53 I2 min RA8m 4.5/8.0 center minute of right ascension (J2000)
55- 58 F4.1 s RA8s 4.5/8.0 center second of right ascension (J2000)
60 A1 --- DE8- [+] 4.5/8.0 center sign of declination (J2000)
61- 62 I2 deg DE8d [15/31] 4.5/8.0 center degree of declination (J2000)
64- 65 I2 arcmin DE8m 4.5/8.0 center arcminute of declination (J2000)
67- 68 I2 arcsec DE8s 4.5/8.0 center arcsecond of declination (J2000)
70- 73 F4.1 arcmin Dim1 [5/95] Dimension 1
75 A1 --- --- [x]
77- 81 F5.1 arcmin Dim2 [5/199] Dimension 2
83- 87 F5.1 deg PA [77/177.5] Position angle of the long axis
of the map
89- 93 F5.1 s Exp [10/241.2] Total exposure time for each
position and filter
95- 97 A3 --- HDR HDR: 0.4s exposure was also obtained
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 I8 --- AOR [3662080/24248576] Spitzer AOR number
10- 14 I5 --- PID [6/40844] Spitzer program ID
16- 26 A11 "Y/M/D" Date UT date of the observation
28- 29 I2 h RAh [4/5] 24um center hour of right ascension (J2000)
31- 32 I2 min RAm 24um center minute of right ascension (J2000)
34- 37 F4.1 s RAs 24um center second of right ascension (J2000)
39 A1 --- DE- [+] 24um center sign of declination (J2000)
40- 41 I2 deg DEd [15/31] 24um center degree of declination (J2000)
43- 44 I2 arcmin DEm 24um center arcminute of declination (J2000)
46- 47 I2 arcsec DEs 24um center arcsecond of declination (J2000)
49- 53 F5.1 arcmin Dim1 [5/111] Dimension 1
55 A1 --- --- [x]
57- 61 F5.1 arcmin Dim2 [8/385.3] Dimension 2
63- 67 F5.1 deg PA [166.7/176] Position angle of the long axis
of the map
69- 73 F5.1 s Exp [15/950] Total exposure time for each position
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table[45].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- 2MASS 2MASS identifier (II/246) if any
(JHHMMSSss+DDMMSSs)
19- 39 A21 --- Name Common name if any
41- 42 I2 pix Ap [15/70]? Aperture radius (1pixel=0.86");
only for table 5
44- 48 F5.2 mag 3.6mag [5.8/15.4]? Spitzer/IRAC [3.6] band magnitude
50- 53 F4.2 mag e_3.6mag [0.02/0.3]? 3.6mag uncertainty
55 A1 --- f_3.6mag Flag on 3.6mag (1)
57- 61 F5.2 mag 4.5mag [5/13.9]? Spitzer/IRAC [4.5] band magnitude
63- 66 F4.2 mag e_4.5mag [0.02/0.2]? 4.5mag uncertainty
68 A1 --- f_4.5mag Flag on 4.5mag (1)
70- 74 F5.2 mag 5.8mag [2.5/13.7]? Spitzer/IRAC [5.8] band magnitude
76- 79 F4.2 mag e_5.8mag [0.03/0.3]? 5.8mag uncertainty
81 A1 --- f_5.8mag Flag on 5.8mag (1)
83- 87 F5.2 mag 8.0mag [2.7/13.9]? 8.0mag uncertainty
89- 92 F4.2 mag e_8.0mag [0.03/0.2]? 8.0mag uncertainty
94 A1 --- f_8.0mag Flag on 8.0mag (1)
96-106 A11 "Y/M/D" Date Observation date
--------------------------------------------------------------------------------
Note (1): Flag as follows:
n = non-detection
o = position outside the field of view of the camera
s = saturation
b = "bad"; contamination by a cosmic ray
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- 2MASS 2MASS identifier (II/246) if any
(JHHMMSSss+DDMMSSs)
19- 39 A21 --- Name Common name if any
41 A1 --- f_Name [b] b = MHO 2: 2MASS J04142639+2805597
43- 46 F4.2 mag 24mag [0.5/9.9]? Spitzer/MIPS [24] band magnitude (1)
48- 51 F4.2 mag e_24mag [0.04/0.3]? 24mag uncertainty
53 A1 --- f_24mag Flag on 24mag (s=saturation or o=outside the
field of view)
55- 65 A11 "Y/M/D" Date Observation date
--------------------------------------------------------------------------------
Note (1): Blank values are non-detection except flagged "s" or "o".
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- 2MASS 2MASS identifier (II/246) if any
(JHHMMSSss+DDMMSSs)
19- 39 A21 --- Name Common name if any
41 A1 --- l_SpT Limit flag on SpT
42- 48 A7 --- SpT MK spectral type (1)
50 A1 --- f_SpT [c] Flag on SpT (2)
52- 56 F5.2 --- 2-8um [-2.8/2.3]? 2-8um observed α slope (3)
58- 62 F5.2 --- 2-8um0 ? 2-8um α slope; dereddened (3)
64- 68 F5.2 --- 2-24um [-2.9/1.4]? 2-24um observed α slope (3)
70- 74 F5.2 --- 2-24um0 ? 2-24um α slope; dereddened (3)
76 A1 --- f_2-24um [b] Flag on 2-24um (2)
78- 82 F5.2 --- 3.6-8um [-2.9/2.2]? 3.6-8um observed α slope (3)
84- 88 F5.2 --- 3.6-8um0 ? 3.6-8um α slope; dereddened (3)
90- 94 F5.2 --- 3.6-24um [-3/2.3]? 3.6-24um observed α slope (3)
96-100 F5.2 --- 3.6-24um0 ? 3.6-24um α slope; dereddened (3)
102 A1 --- f_3.6-24um [b] Flag on 3.6-24um (2)
104-107 A4 --- Cl SED class
--------------------------------------------------------------------------------
Note (1): As indicated in the erratum 2010, ApJS, 189, 353, the CDS added the
spectral type bins for FT Tau, DK Tau B, IRAS 04370+2559,
IRAS 04200+2759, IT Tau B, ITG 1 and IRAS 04325+2402 C.
Note (2): Flag as follows:
b = Because this multiple system is unresolved at 24um, this slope was
computed with the total flux of the system in the band at the shorter
wavelength.
c = The spectral type bin in which this source was placed in Table 8 based
on its bolometric luminosity.
Note (3): Only the observed values are listed if extinction estimates are
unavailable.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 11-Mar-2016