J/AJ/145/94 Luminosities of protostars from two Spitzer surveys (Dunham+, 2013)
The luminosities of protostars in the Spitzer c2d and Gould Belt Legacy clouds.
Dunham M.M., Arce H.G., Allen L.E., Evans II N.J., Broekhoven-Fiene H.,
Chapman N.L., Cieza L.A., Gutermuth R.A., Harvey P.M., Hatchell J.,
Huard T.L., Kirk J.M., Matthews B.C., Merin B., Miller J.F., Peterson D.E.,
Spezzi L.
<Astron. J., 145, 94 (2013)>
=2013AJ....145...94D 2013AJ....145...94D
ADC_Keywords: Molecular clouds ; YSOs ; Extinction ; Millimetric/submm sources ;
Infrared sources
Keywords: stars: formation - stars: low-mass - stars: protostars -
stars: luminosity function, mass function
Abstract:
Motivated by the long-standing "luminosity problem" in low-mass star
formation whereby protostars are underluminous compared to theoretical
expectations, we identify 230 protostars in 18 molecular clouds
observed by two Spitzer Space Telescope Legacy surveys of nearby
star-forming regions. We compile complete spectral energy
distributions, calculate Lbol for each source, and study the
protostellar luminosity distribution. This distribution extends over
three orders of magnitude, from 0.01L☉ to 69L☉, and has a
mean and median of 4.3L☉ and 1.3L☉, respectively. The
distributions are very similar for Class 0 and Class I sources except
for an excess of low luminosity (Lbol≲0.5L☉) Class I sources
compared to Class 0. 100 out of the 230 protostars (43%) lack any
available data in the far-infrared and submillimeter
(70µm<λ<850µm) and have Lbol underestimated by factors
of 2.5 on average, and up to factors of 8-10 in extreme cases.
Correcting these underestimates for each source individually once
additional data becomes available will likely increase both the mean
and median of the sample by 35%-40%. We discuss and compare our
results to several recent theoretical studies of protostellar
luminosities and show that our new results do not invalidate the
conclusions of any of these studies. As these studies demonstrate that
there is more than one plausible accretion scenario that can match
observations, future attention is clearly needed. The better
statistics provided by our increased data set should aid such future
work.
Description:
We studied the protostellar luminosity distribution based on data for
230 protostars (Table2) from two Spitzer Space Telescope (SST) Legacy
surveys of nearby star-forming regions (the Legacy survey "From
Molecular Cores to Planet Forming Disks", SSTc2d, Evans et al.,
2003PASP..115..965E 2003PASP..115..965E; and the Gould Belt Legacy Survey of the Spitzer
Space Telescope; SSTgb, L. Allen et al., in preparation).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 82 230 List of protostars and basic properties
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See also:
J/AJ/144/31 : Spitzer+2MASS phot. of protostar candidates (Kryukova+, 2012)
J/A+A/527/A145 : Chamaeleon I 870um sources (Belloche+, 2011)
J/ApJS/194/43 : YSOs candidates and knots in CrA cloud (Peterson+, 2011)
J/A+A/535/A2 : Chamaeleon III 870um sources maps (Belloche+, 2011)
J/ApJS/186/259 : Taurus Spitzer survey: new candidate members (Rebull+, 2010)
J/ApJ/714/778 : YSOs in the Serpens Molecular Cloud (Oliveira+, 2010)
J/ApJ/692/973 : Protostars in Perseus, Serpens and Ophiuchus (Enoch+, 2009)
J/ApJS/181/321 : Properties of Spitzer c2d dark clouds (Evans+, 2009)
J/ApJ/691/672 : YSOs spectroscopy in Serpens molecular cloud (Oliveira+ 2009)
J/ApJS/185/198 : The Cepheus flare observed with IRAC and MIPS (Kirk+, 2009)
J/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)
J/ApJ/684/1240 : Prestellar cores in Perseus, Serpens, Ophiuchus (Enoch+, 2008)
J/ApJ/680/495 : Survey of Interstellar clouds in Gould belt (Harvey+, 2008)
J/ApJS/177/551 : Spitzer c2d survey of Lupus dark clouds (Merin+, 2008)
J/ApJ/676/427 : MIPS and IRAC data on ChaII PMS stars (Alcala+, 2008)
J/ApJ/663/1149 : Spitzer survey of Serpens YSO population (Harvey+, 2007)
J/AJ/133/1560 : Spitzer c2d small clouds and cores (Wu+, 2007)
J/ApJ/638/293 : 1.1mm sources in the Perseus Molecular Cloud (Enoch+, 2006)
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 [1/230] Protostar running sequence number
5- 21 A17 --- Cloud Cloud in which the protostar is located (1)
23- 37 A15 --- Name Protostar Spitzer name (JHHMMSSs+DDMMSSs) (2)
39- 42 F4.1 mag AV [0/30] Extinction in V-band (used for dereddening;
see Section 2.3 for more details)
44- 48 F5.2 --- alpha ? Observed infrared spectral index (α)
50- 53 I4 K Tbol [7/2700] Observed bolometric temperature
55- 61 F7.4 Lsun Lbol [0.0076/69] Observed bolometric luminosity
63- 67 F5.2 --- alpha0 ? Infrared spectral index (α0
corrected for extinction)
69- 72 I4 K Tbol0 Bolometric temperature (corrected for extinction)
74- 80 F7.4 Lsun Lbol0 Bolometric luminosity (corrected for extinction)
82 A1 --- F [YN] Existence of far-IR/sub-mm data (3)
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Note (1): Aquila, Auriga/California, Cepheus, Chamaeleon I, Chamaeleon II,
Corona Australis, IC5146, Lupus, Ophiuchus, Ophiuchus North, Perseus, or
Serpens.
Note (2): From the Spitzer Space Telescope Legacy survey "From Molecular Cores
to Planet Forming Disks" (SSTc2d; Evans et al., 2003PASP..115..965E 2003PASP..115..965E) or
from the Spitzer Space Telescope Gould Belt Legacy Survey (SSTgb;
L. Allen et al., in preparation, <SSTgbs JHHMMSSs+DDMMSSs> in Simbad).
Note (3): Flag indicating whether the protostar does (Y) or does not (N)
have at least one observed photometry point in the Far-InfraRed or
SubMilliMeter (70µm<λ<850µm. See Section 4.3 for details.
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History:
From electronic version of the journal
(End) Sylvain Guehenneux [CDS] 11-Apr-2014