J/ApJ/874/16 SOFIA Massive Star Formation Survey. II. 7 protostars (Liu+, 2019)
The SOFIA Massive (SOMA) Star Formation Survey.
II. High luminosity protostars.
Liu M., Tan J.C., De Buizer J.M., Zhang Y., Beltran M.T., Staff J.E.,
Tanaka K.E.I., Whitney B., Rosero V.
<Astrophys. J., 874, 16 (2019)>
=2019ApJ...874...16L 2019ApJ...874...16L
ADC_Keywords: Photometry, infrared; Interstellar medium; Star Forming Region
Keywords: dust, extinction ; infrared: stars ; ISM: jets and outflows ;
stars: early-type ; stars: formation
Abstract:
We present multiwavelength images observed with SOFIA-FORCAST from ∼10
to 40µm of seven high luminosity massive protostars, as part of the
SOFIA Massive Star Formation Survey. Source morphologies at these
wavelengths appear to be influenced by outflow cavities and extinction
from dense gas surrounding the protostars. Using these images, we
build spectral energy distributions (SEDs) of the protostars, also
including archival data from Spitzer, Herschel, and other facilities.
Radiative transfer (RT) models of Zhang & Tan (2018ApJ...853...18Z 2018ApJ...853...18Z),
based on Turbulent Core Accretion theory, are then fit to the SEDs to
estimate key properties of the protostars. Considering the best five
models fit to each source, the protostars have masses m*∼12-64M☉
accreting at rates of dm/dt*∼10-4-10-3M☉/yr inside cores
of initial masses Mc∼100-500M☉ embedded in clumps with mass
surface densities Σcl∼0.1-3g/cm2 and span a luminosity range
of 104-106L☉. Compared with the first eight protostars in
Paper I (De Buizer+ 2017ApJ...843...33D 2017ApJ...843...33D), the sources analyzed here
are more luminous and, thus, likely to be more massive protostars.
They are often in a clustered environment or have a companion
protostar relatively nearby. From the range of parameter space of the
models, we do not see any evidence that Σcl needs to be high to
form these massive stars. For most sources, the RT models provide
reasonable fits to the SEDs, though the cold clump material often
influences the long wavelength fitting. However, for sources in very
clustered environments, the model SEDs may not be such a good
description of the data, indicating potential limitations of the
models for these regions.
Description:
The following seven sources, listed in order of decreasing isotropic
bolometric luminosity, were observed by SOFIA with the FORCAST
instrument (see Table 1): G45.12+0.13; G309.92+0.48; G35.58-0.03;
IRAS 16562-3959; G305.20+0.21; G49.27-0.34; G339.88-1.26 in
2016 July 14, 17, 18, 20 and 2016 Sep 17, 20.
For all objects, data were retrieved from the Spitzer Heritage Archive
from all four Infrared Array Camera (IRAC) channels (3.6, 4.5, 5.8,
and 8.0um).
We also incorporated publicly available imaging observations performed
with the Herschel Space Observatory and its Photodetector Array Camera
and Spectrometer (PACS) and Spectral and Photometric Imaging Receiver
(SPIRE) instruments at 70, 160, 250, 350, and 500um.
We also present previously unpublished Gemini 8m data taken with the
instrument T-ReCS for sources G309.92, G35.58, and G305.20. For both
G309.92 and G35.58, only 11.7um data were taken, with on-source
exposures times of 304s and 360s, respectively. For G305.20, we have
images through 10 T-ReCS filters from 3.8um (L-band) to 24.5um, all
with an exposure time of 130s.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 85 7 SOFIA-FORCAST observations: observation dates and
exposure times
fluxes.dat 75 91 Integrated flux densities (from Table 2)
table4.dat 77 35 Parameters of the best five fitted models
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Description of file:
table2.dat.gz in the FTP section is the original Table 2 given in the paper,
ordered by wavelength.
See also:
II/319 : UKIDSS-DR9 LAS, GCS and DXS Surveys (Lawrence+ 2012)
II/328 : AllWISE Data Release (Cutri+ 2013)
J/ApJS/91/659 : Ultracompact HII regions radio images (Kurtz+ 1994)
J/MNRAS/291/261 : Methanol maser of IRAS-selected sources (Walsh+ 1997)
J/MNRAS/301/640 : Ultracompact H II regions studies. II. (Walsh+, 1998)
J/ApJ/587/714 : H2CO and Hα observations of UC HII (Watson+, 2003)
J/ApJ/702/1615 : CH3OH maser survey of EGOs (Cyganowski+, 2009)
J/ApJ/707/89 : Variation of mid-IR extinction (Gao+, 2009)
J/A+A/510/A89 : RMS survey of young massive stars in far-IR (Mottram+, 2010)
J/A+A/525/A149 : Red MSX Survey (RMS): YSO bolometric fluxes (Mottram+, 2011)
J/A+A/534/A131 : Clumps in the giant molecular cloud G345.5+1.0 (Lopez+, 2011)
J/A+A/558/A24 : The VLTI/MIDI survey of Massive YSOs (Boley+, 2013)
J/A+A/593/A49 : G35.20-0.74N VLA continuum images (Beltran+, 2016)
J/A+A/595/A88 : G345.45+1.50 13CO(3-2) clumps (Lopez-Calderon+, 2016)
J/ApJ/843/33 : SOMA Star Formation Survey. Paper I. (De Buizer+, 2017)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 A14 --- Name Name of the protostar
16- 17 I2 h RAh Hour of right ascension (J2000)
19- 20 I2 min RAm Minute of right ascension (J2000)
22- 27 F6.3 s RAs Second of right ascension (J2000)
29 A1 --- DE- Sign of declination (J2000)
30- 31 I2 deg DEd Degree of declination (J2000)
33- 34 I2 arcmin DEm Arcminute of declination (J2000)
36- 41 F6.3 arcsec DEs Arcsecond of declination (J2000)
43- 47 F5.2 kpc Dist [1.7/10.2] Distance
49- 50 I2 arcsec Rap [16/48] Aperture radius in arcsec
52- 55 F4.2 pc Rap_pc [0.26/1.72] Aperture radius in pc
57- 67 A11 "date" Date UT date of observation
69- 72 I4 s Exp7.7 [290/2443] 7.7um exposure time
74- 76 I3 s Exp19.7 [716/882] 19.7um exposure time
78- 80 I3 s Exp31.5 [502/664] 31.5um exposure time
82- 85 I4 s Exp37.1 [1028/1691] 37.1um exposure time
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Byte-by-byte Description of file: fluxes.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 A14 --- Name Source identifier
16- 32 A17 --- Tel Facility
34- 38 F5.1 um lambda [3.4/500] Wavelength
40- 46 F7.2 Jy Ffix [0.1/5848]? Fixed aperture flux
density with background subtraction
48- 54 F7.2 Jy Ffixpre [0.3/6205]? Fixed aperture flux
density without background subtraction
56- 62 F7.2 Jy Fvar [0.05/5848]? Variable aperture
flux density with background subtraction
64- 70 F7.2 Jy Fvarpre [0.07/6205]? Variable aperture flux
density without background subtraction
72- 75 F4.1 arcsec Rap [2/48]? Aperture radius
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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- 14 A14 --- Name Source identifier
16- 20 F5.2 --- chi2 [0.53/69.3] Model χ2/degrees of
freedom
22- 24 I3 Msun Mc [80/480] Initial core mass
26- 28 F3.1 g/cm2 Sigma [0.1/3.2] Clump mean mass surface density
30- 34 F5.3 pc Rc-Phy [0.03/0.51] Physical initial core radius
36- 37 I2 arcsec Rc-Ang [1/62] Angular initial core radius
39- 42 F4.1 Msun M* [12/64] Current protostellar mass
44- 45 I2 deg theta [13/71] Viewing angle
47- 51 F5.1 mag Av [0/100] Foreground extinction in the V band
53- 55 I3 Msun Menv [35/459] Current envelope mass
57- 58 I2 deg theta-esc [10/45] Half opening angle of outflow cavity
60- 65 E6.1 Msun/yr dM/dt [0.00014/0.002] Disk accretion rate to star
67- 71 E5.1 Lsun Liso [33000/1300000] Bolometric luminosity
assuming isotropic radiation
73- 77 E5.1 Lsun Lbol [40000/840000] True bolometric luminosity,
inclination corrected
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History:
From electronic version of the journal
References:
De Buizer et al. Paper I. 2017ApJ...843...33D 2017ApJ...843...33D Cat. J/ApJ/843/33
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 26-Aug-2020