J/ApJ/769/149 IR spectroscopy in Orion A: transitional disks (Kim+, 2013)
Transitional disks and their origins: an infrared spectroscopic survey of
Orion A.
Kim K.H., Watson D.M., Manoj P., Forrest W.J., Najita J., Furlan E.,
Sargent B., Espaillat C., Muzerolle J., Megeath S.T., Calvet N.,
Green J.D., Arnold L.
<Astrophys. J., 769, 149 (2013)>
=2013ApJ...769..149K 2013ApJ...769..149K
ADC_Keywords: Spectra, infrared ; YSOs ; Accretion ; Spectral types
Keywords: accretion, accretion disks; infrared: stars; protoplanetary disks;
stars: pre-main sequence; X-rays: stars
Abstract:
Transitional disks are protoplanetary disks around young stars, with
inner holes or gaps which are surrounded by optically thick outer, and
often inner, disks. Here we present observations of 62 new
transitional disks in the Orion A star-forming region. These were
identified using the Spitzer Space Telescope's Infrared Spectrograph
and followed up with determinations of stellar and accretion
parameters using the Infrared Telescope Facility's SpeX. We combine
these new observations with our previous results on transitional disks
in Taurus, Chamaeleon I, Ophiuchus, and Perseus, and with archival
X-ray observations. This produces a sample of 105 transitional disks
of "cluster" age 3Myr or less, by far the largest hitherto assembled.
We use this sample to search for trends between the radial structure
in the disks and many other system properties, in order to place
constraints on the possible origins of transitional disks. We see a
clear progression of host-star accretion rate and the different disk
morphologies. We confirm that transitional disks with complete central
clearings have median accretion rates an order of magnitude smaller
than radially continuous disks of the same population.
Pre-transitional disks--those objects with gaps that separate inner
and outer disks--have median accretion rates intermediate between the
two. Our results from the search for statistically significant trends,
especially related to dM/dt, strongly support that in both cases the
gaps are far more likely to be due to the gravitational influence of
Jovian planets or brown dwarfs orbiting within the gaps, than to any
of the photoevaporative, turbulent, or grain-growth processes that can
lead to disk dissipation. We also find that the fraction of Class II
YSOs which are transitional disks is large, 0.1-0.2, especially in the
youngest associations.
Description:
We observed the Orion A star-forming region between 2006 November and
2007 October, during Spitzer/IRS campaigns 36, 39, 40, and 44. In all,
our targets were 555 objects selected on the basis of their
Spitzer/IRAC and MIPS colors to belong to YSO Classes 0, I,
flat-spectrum, and II.
We observed 241 objects (114 in L1641; 127 in ONC) with the IRS with
full IRS wavelength coverage of 5-37um in the low-resolution mode. The
IRS spectra of the 62 transitional disks (TDs) were selected from
among the 241 objects which were observed with the IRS low-resolution
modules (λ/Δλ∼90; short-low (SL): 5.3-14um;
long-low (LL): 14-38um)
Out of 62 transitional objects in Orion A, 52 were observed at near-IR
(0.8-2.4um) wavelengths with the medium resolution spectrograph SpeX,
on the NASA Infrared Telescope Facility (IRTF) on Mauna Kea during the
2010A, 2011A, and 2011B semesters.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 100 62 Observation and reduction log of IRS spectra
table2.dat 49 52 Observation log of SpeX spectra
table3.dat 45 62 Spectral type and extinction
table4.dat 94 105 Stellar and disk properties
table5.dat 48 105 Subclassification of transitional disks (TDs)
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See also:
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
J/A+A/564/A29 : Optical and near-infrared photometry in Orion A (Bouy+, 2014)
J/ApJ/767/36 : Herschel & APEX obs. in Orion: protostars (Stutz+, 2013)
J/ApJS/207/10 : HST Treasury Program on the ONC (Robberto+, 2013)
J/AJ/144/192 : Spitzer survey of Orion A and B. I. YSO (Megeath+, 2012)
J/ApJ/752/59 : Low-mass population in L1641 (Hsu+, 2012)
J/ApJ/731/8 : Multiple star formation in Taurus-Auriga (Kraus+, 2011)
J/A+A/515/A13 : Very low mass objects in ONC (Rodriguez-Ledesma+, 2010)
J/ApJ/712/925 : Transition circumstellar disks in Ophiuchus (Cieza+, 2010)
J/ApJ/710/597 : Accretion in disks in Cep OB2 (Sicilia-Aguilar+, 2010)
J/AJ/140/266 : NGC 1333 X-ray luminous YSOs properties (Winston+, 2010)
J/A+A/504/461 : YSOs in L1630N and L1641 (Fang+, 2009)
J/ApJS/183/261 : Optical photometry of the ONC (Da Rio+, 2009)
J/ApJ/703/1964 : Spectra of three nearby star-forming regions (Furlan+, 2009)
J/ApJ/698/1 : Spitzer observations of NGC 2362 (Currie+, 2009)
J/ApJ/697/1103 : Kinematics of Orion Nebula Cluster (Tobin+, 2009)
J/ApJ/693/L81 : Extinction in star-forming regions (McClure, 2009)
J/A+A/493/339 : XMM-Newton serendipitous Survey. V. (Watson+, 2009)
J/MNRAS/400/603 : New variables in ONC (Parihar+, 2009)
J/A+A/489/1409 : IR photometry and spectroscopy in L1641N (Galfalk+, 2008)
J/A+A/468/353 : XMM-Newton Extended Survey of Taurus (Guedel+, 2007)
J/ApJ/671/605 : NGC 2264 and ONC PMS stars in the infrared (Cieza+, 2007)
J/A+A/452/245 : Near-IR photometry of PMS stars in rho Oph (Natta+, 2006)
J/ApJ/646/297 : Spitzer obs. of pre-main-sequence stars (Rebull+, 2006)
J/AJ/131/1574 : Infrared photometry of IC348 members (Lada+, 2006)
J/ApJS/160/353 : Membership of the Orion nebula population (Getman+, 2005)
J/AJ/125/1537 : QUIRC Chandra sources in OMC 2/3 (Tsujimoto+, 2003)
J/AJ/119/3026 : Circumstellar disk candidates in Orion (Rebull+, 2000)
J/A+A/337/403 : Low-mass stars evolutionary models (Baraffe+ 1998)
J/AJ/113/1733 : Orion Nebula Cluster population (Hillenbrand 1997)
J/ApJS/101/117 : UBVRIJHKLMNQ photometry in Taurus-Auriga (Kenyon+ 1995)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [1/303] Sequence number (G1)
5- 16 A12 --- IRS Infra-Red Spectrograph source name
18- 33 A16 --- 2MASS ? 2MASS name (HHMMSSss+DDMMSSs; J2000);
35- 36 I2 h RAh Hour of right ascension (J2000)
38- 39 I2 min RAm Minute of right ascension (J2000)
41- 45 F5.2 s RAs Second of right ascension (J2000)
47 A1 --- DE- Sign of declination (J2000)
48- 49 I2 deg DEd Degree of declination (J2000)
51- 52 I2 arcmin DEm Arcminute of declination (J2000)
54- 57 F4.1 arcsec DEs Arcsecond of declination (J2000)
59- 66 I8 --- AOR Spitzer/IRS AOR identification number
68- 69 I2 --- Camp [36/44] Spitzer/IRS campaign number
71- 81 A11 "YYYY/MMM/DD" DateIRS Date of Spitzer/IRS observation
83- 87 A5 --- Reg Region identifier (L1641 or ONC)
89- 98 A10 --- Reduc Reduction (1)
100 A1 --- f_Reduc Flag on Reduc (2)
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Note (1): Indicates the methods of source extraction to get the SEDs in Fig.2:
auto = an automated tapered column extraction in SMART with off-nod or
off-order sky subtraction;
man = a manual tapered column extraction in SMART with a polynomial sky
subtraction;
AdOpt = an optimal source extraction using an empirical point response
function (PRF) in SMART;
opse = an optimal source extraction using an analytical point response
function (PRF);
Note (2): Flag as follows:
a = SL and LL1: opsew7p; LL2: AdOpt.
b = SL (5.3-14um): AdOpt; LL (14-38um): opse.
c = SL: opse; LL:AdOpt.
d = SL: AdOpt; LL: auto onss.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/303] Sequence number (G1)
5- 16 A12 --- IRS Infra-Red Spectrograph source name
18- 22 A5 --- Sem SpeX observation semester
24- 34 A11 "YYYY/MMM/DD" DateSpeX UT date of SpeX observation
36- 38 F3.1 arcsec Slit [0.3/0.8] SpeX slit width
40- 43 I4 s Tint [120/2520] SpeX total integration time
45- 49 A5 --- Comm Comment(s) (3)
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Note (3): Flag as follows:
a = The source signal on order eight is very faint, so that order eight source
extraction failed.
b = It is a binary system with two sources resolved from SpeX observations.
The possible primary source giving the adopted dM/dt in table 4 is
presented in the black line from 0.8 to 2.4um in Figure 2. The possible
secondary is presented in the gray line in the same plot.
c = The position angle of slit was 27°.
d = Resolved two sources on the guider image are dominantly displaced in the
north-south direction with slight separation in east-west direction.
e = Four among 6x120s exposures are combined in the spectrum.
f = The two sources are aligned to N-S direction.
g = The source signals in orders 6, 7, and 8 is very faint so that source
extraction for order 6-8 failed.
h = The position angle of slit was -20°.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [1/303] Sequence number (G1)
5- 16 A12 --- IRS Infra-Red Spectrograph source name
18- 21 A4 --- SpT MK spectral type
23- 30 A8 --- r_SpT SpT reference or method (4)
32- 36 F5.2 mag Av [0/21.3] V-band extinction
38- 45 A8 --- Meth Av method
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Note (4): Flag as follows:
a = L. Allen & G. Mosby (2008, private communication); spectral types are
measured from HECTOSPEC spectra; updated spectral types are available
from Hsu et al. (2012, J/ApJ/752/59).
a2 = L. Allen & G. Mosby (2008, private communication); spectral types are
measured from HECTOSPEC spectra, spectral types are highly uncertain;
updated spectral types are available from Hsu et al. (2012,
J/ApJ/752/59).
b = Hillenbrand (1997, J/AJ/113/1733).
c = Rebull et al. (2000, J/AJ/119/3026).
d = Allen (1995PhDT..........A 1995PhDT..........A).
e = J. Hernandez (2008, private communication); spectral types measured from
MDM spectroscopic data, using the SPTCLASS code
(http://dept.astro.lsa.umich.edu/~hernandj/SPTclass/sptclass.html).
f = J. Hernandez & J. Tobin (2009, private communication); spectral types
are measured from HECTOSPEC spectra, using the SPTCLASS code.
f2 = J. Hernandez & J. Tobin (2009, private communication); spectral types
are measured from FAST spectra, using the SPTCLASS code.
g = Da Rio et al. (2010, J/ApJS/183/261).
h = Fang et al. (2009, J/A+A/504/461).
i = Parihar et al. (2009, J/MNRAS/400/603).
i2 = It is M3.6 from Parihar et al. (2009, J/MNRAS/400/603), but
for our analysis convenience we take it as M3.5.
SpeX = spectral typing with SpeX spectra in this work.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- ID Identifications numbers if any
10- 21 A12 --- Name Source name (IRS or other name)
23- 26 I4 K Teff [3145/6030] Effective temperature
28- 32 F5.2 Lsun L* [0.02/62.4] Stellar luminosity
34- 37 F4.2 Msun M* [0.2/3.4] Stellar mass
39- 43 F5.1 AU Rwall [2.2/138.2] Radius of transitional disk from
IRS spectrum (1)
45- 47 A3 --- Type Transition disk type (G2)
49 A1 --- l_dM/dt Limit flag on dM/dt
51- 58 E8.3 Msun/yr dM/dt ? Mass accretion rate (2)
60- 66 E7.2 Msun/yr e_dM/dt ? dM/dt uncertainty
68 A1 --- f_dM/dt Flag on dM/dt (3)
70- 76 E7.2 10-7W LX ? Luminosity in 0.2-12keV total energy band (4)
78- 84 E7.2 10-7W e_LX ? LX uncertainty
86- 90 A5 --- Reg Region identifier (L1641 or ONC)
91- 94 A4 --- f_Reg Ophiuchus "core" or "off"
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Note (1): The calculation of Rwall, radius at which the inner wall of the
optically thick outer disk lies, is explained in Section 4.2, and the
values listed in the column have an uncertainty of about 33%.
Note (2): dM/dt of ONC and L1641 is from this work. dM/dt for other regions
are fIRS name or namerom the literatures.
Note (3): Flag as follows:
a = Najita et al. (2007MNRAS.378..369N 2007MNRAS.378..369N). b = Espaillat et al.
(2011ApJ...728...49E 2011ApJ...728...49E). c = Guedel et al. (2007, J/A+A/468/353). d =
Natta et al. (2006, J/A+A/452/245).
Note (4): LX are all from XMM-Newton Serendipitous Source Catalog (Watson
et al. 2009, Cat. J/A+A/493/339).
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- ID Identification number if any
10- 21 A12 --- Name Source name (IRS or other name)
23- 27 A5 --- Reg Region identifier (L1641 or ONC)
29 A1 --- K-6 [Y/N ] Criteria of nK-6 passed? (5)
31 A1 --- 13-31 [Y/N ] Criteria of n13-31 passed? (5)
33 A1 --- 10um [Y/N ] Criteria of EW(10um) passed? (5)
35- 37 A3 --- Type Transitional disk subtype (CTD, WTD or PTD)
based on IDEF value (G2)
39 A1 --- f_Type [ab] Mismatched Transition Disk criteria (7)
41- 45 F5.2 --- IDEF [-0.8/1.8] Inner disk excess fraction
47- 48 A2 --- f_IDEF Flag on IDEF (7)
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Note (5): The continuum spectral indices are defined as:
nλ1-λ2 =
log[λ2F(λ2)/λ1F(λ1)]
/ log[λ2/λ1]
The equivalent width of the 10um silicate emission feature (EW(10um))
is a measure of the amount of optically thin dust per unit area of
optically thick disk.
See section 4.1 for further explanations.
Note (7): Flag as follows:
a = OriA-44 and OriA-176 do not pass nK-6, n13-31, and EW(10um), but
their SEDs resemble a TD's SED.
b = We did not calculate its spectral indices because its IRS spectrum is not
complete, but its SED resemble a TD's SED.
c = OriA-8 and OriA-172 are selected as CTDs, but IDEF>0.25. The spectral
type of the objects is M3 or later. When measuring ef using the median
spectrum of objects with M3-M5 in Tau, the IDEF values are 0.45 and
0.65, respectively.
d = OriA-23 and OriA-198 are selected as WTDs with IDEF=0.51. The spectral
type of objects is M0 and K6.5, respectively.
e1 = OriA-149 and OriA-164 have IDEF<0.5, but they are selected as PTD because
we do not know their spectral types, but the fluxes at wavelength ranges
of 2-6um are comparable to that of the median spectrum.
e2 = T35 (Sz 27) and 16126-2607 are PTDs, but their IDEF are slightly less
than 0.5. Their spectral types are M0 and K7, respectively.
e3 = Baud 43 and 16126-2235 are PTDs, but their IDEF are less than 0.5. Their
spectral types are M3.25 and M3.0, respectively. When measuring IDEF
using the median spectrum of objects with M3-M5 in Tau, the IDEF values
are 0.72 and 0.71, respectively.
f = OriA-5, OriA-301, 04202606, GY 195, LAL 106, and LAL 245 have spectral
types of M3 or later. Their IDEF estimated with K5-M2 median spectrum are
higher than 0.5 and they are classified as PTDs. The IDEF estimated with
M3-M5 median spectrum are much higher than the IDEF listed in this table:
0.94, 1.07, 0.87, 1.0, 1.5, and 1.14, respectively.
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Global notes:
Note (G1): The numbers are from the number sequence of 303 Class II objects
observed in the IRS program number 30706. We use these numbers to
identify objects easily. This number sequence will be used consistently
in other future papers dealing with the objects in the PID 30706.
Note (G2): Subtypes are (section 4.1.1):
CTD = Classical transitional disk (e.g. DM Tau)
WTD = Weak-excess transitional disk (e.g. GM Aur)
PTD = Pre-transitional disk (e.g. LkCa 15)
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 18-Dec-2014