J/ApJ/911/153 HST 1.60um & 2.05um images of protostars in Orion (Habel+, 2021)
An HST survey of protostellar outflow cavities: does feedback clear envelopes?
Habel N.M., Thomas Megeath S., Jon Booker J., Fischer W.J., Kounkel M.,
Poteet C., Furlan E., Stutz A., Manoj P., Tobin J.J., Nagy Z., Pokhrel R.,
Watson D.
<Astrophys. J., 911, 153 (2021)>
=2021ApJ...911..153H 2021ApJ...911..153H
ADC_Keywords: YSOs; Molecular clouds; Infrared sources
Keywords: Protostars ; Stellar feedback ; Molecular clouds ;
Near infrared astronomy ; Stellar jets ; Early stellar evolution
Abstract:
We study protostellar envelope and outflow evolution using Hubble
Space Telescope NICMOS or WFC3 images of 304 protostars in the Orion
molecular clouds. These near-IR images resolve structures in the
envelopes delineated by the scattered light of the central protostars
with 80au resolution, and they complement the 1.2µm to 870µm
spectral energy distributions (SEDs) obtained with the Herschel Orion
Protostar Survey program. Based on their 1.60µm morphologies, we
classify the protostars into five categories: nondetections, point
sources without nebulosity, bipolar cavity sources, unipolar cavity
sources, and irregulars. We find point sources without associated
nebulosity are the most numerous, and show through monochromatic Monte
Carlo radiative transfer modeling that this morphology occurs when
protostars are observed at low inclinations or have low envelope
densities. We also find that the morphology is correlated with the
SED-determined evolutionary class, with Class 0 protostars more likely
to be nondetections, Class I protostars to show cavities, and
flat-spectrum protostars to be point sources. Using an edge detection
algorithm to trace the projected edges of the cavities, we fit power
laws to the resulting cavity shapes, thereby measuring the cavity
half-opening angles and power-law exponents. We find no evidence for
the growth of outflow cavities as protostars evolve through the
Class I protostar phase, in contradiction with previous studies of
smaller samples. We conclude that the decline of mass infall with time
cannot be explained by the progressive clearing of envelopes by
growing outflow cavities. Furthermore, the low star formation
efficiency inferred for molecular cores cannot be explained by
envelope clearing alone.
Description:
The HST observations were assembled from two GO programs and a
snapshot program. The bulk of the sample was observed in program
GO 11548. The Near Infrared Camera and Multi-Object Spectrometer's
(NICMOS) F205W and F160W filters were used for a total of 87 orbits in
August and September of 2008 to image 92 objects in the HOPS catalog.
After the 2009 June deployment of the Wide Field Camera 3 (WFC3),
126 orbits were used between 2009 August and 2010 December to observe
237 HOPS objects with the F160W filter. The observation and reduction
of these data is described in Kounkel+ (2016, J/ApJ/821/52).
A subsequent program using WFC3, SNAP 14181, was designed to target
multiple star-forming regions within 500pc. It completed observations
during 114 orbits between 2015 December and 2017 September, 10 of
which imaged 13 objects in the Orion molecular clouds. A final WFC3
study, program GO 14695, targeted four objects in Orion with weak 24um
fluxes atypical of protostars. These observations were conducted in
2016 September with four orbits.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 78 304 All HST sources
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See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
J/A+A/291/943 : Protostellar cores (Ossenkopf+, 1994)
J/ApJ/566/993 : rho Oph (Lynds 1688) cluster NICMOS imaging (Allen+, 2002)
J/A+A/462/L17 : Dense cores in interstellar molecular clouds (Alves+, 2007)
J/A+A/472/187 : 12CO outflows towards submm cores in Perseus (Hatchell+, 2007)
J/AJ/144/192 : Spitzer survey of Orion A & B. I. YSO catalog (Megeath+, 2012)
J/AJ/145/94 : Luminosities of protostars from Spitzer (Dunham+, 2013)
J/ApJ/767/36 : APEX observations of HOPS protostars (Stutz+, 2013)
J/ApJ/783/6 : Deconvolved Spitzer images of 89 protostars (Velusamy+, 2014)
J/A+A/584/A91 : Dense cores in Aquila from Herschel (Konyves+, 2015)
J/ApJS/224/5 : The Herschel Orion Protostar Survey (HOPS) (Furlan+, 2016)
J/ApJ/821/52 : NIR survey of Spitzer YSOs in Orion MoC (Kounkel+, 2016)
J/A+A/619/A106 : 3D shape of Orion A from Gaia DR2 (Grossschedl+, 2018)
J/AJ/156/84 : APOGEE-2 survey of Orion Complex. II. (Kounkel+, 2018)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- HOPS [1/410] HOPS identifier
5 I1 --- f_HOPS [4/6]? Flag on HOPS (1)
7- 8 I2 h RAh [5] Hour of Right Ascension (J2000)
10- 11 I2 min RAm [33/54] Minute of Right Ascension (J2000)
13- 16 F4.1 s RAs Second of Right Ascension (J2000)
18 A1 --- DE- [±] Sign of the Declination (J2000)
19- 20 I2 deg DEd [0/8] Degree of Declination (J2000)
22- 23 I2 arcmin DEm Arcminute of Declination (J2000)
25- 26 I2 arcsec DEs Arcsecond of Declination (J2000)
28- 31 A4 --- Class SED class (2)
33- 38 F6.1 K Tbol [24.6/1211]? Bolometric temperature (2)
40- 47 A8 --- Inst Instrument (3)
49 A1 --- PS Point source? (4)
51- 63 A13 --- Morph Morphology type from F160W image
65- 69 F5.2 % Vol [0.4/37.6]? Percent volume cleared
71- 74 F4.1 deg Angle [4/50]? Half-opening angle
76- 78 F3.1 --- Fit [1/6.7]? Power-Law fit
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Note (1): Flag as follows:
4 = This source is coincident with the tip of a large pillar in the
surrounding cloud. We judge features surrounding it to be consistent
with a unipolar source but cannot rule out a point source incidentally
appearing with a "false" cavity.
5 = Averaged parameters are reported for these bipolar sources where
both cavities were measured.
6 = Coordinates, class and Tbol are from Stutz et al. (2013, J/ApJ/767/36).
Note (2): From Furlan et al. (2016, J/ApJS/224/5).
Note (3): Objects observed with the instrument NICMOS are noted with
the abbreviation "NIC."
Note (4): Denotes, (yes or no), if the object is observed with an
apparent central point source.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 14-Oct-2022