J/A+A/625/A103 19 highmass SFR Herschel spectra and maps (van der Tak+, 2019)
Multi line Herschel HIFI observations of water reveal infall motions
and chemical segregation around high mass protostars.
van der Tak F.F.S., Shipman R.F., Jacq T., Herpin F., Braine J., Wyrowski F.
<Astron. Astrophys. 625, A103 (2019)>
=2019A&A...625A.103V 2019A&A...625A.103V (SIMBAD/NED BibCode)
ADC_Keywords: Star Forming Region ; Spectroscopy
Keywords: stars: formation - ISM: molecules - astrochemistry
Abstract:
The physical conditions during high-mass star formation are poorly
understood. Outflow and infall motions have been detected around
massive protostellar objects, but their dependence on mass,
luminosity, and age is unclear. In addition, physical conditions and
molecular abundances are often estimated using simple assumptions such
as spherical shape and chemical homogeneity, which may limit the
accuracy of the results.
We aim to characterize the dust and gas distribution and kinematics of
the envelopes of high-mass protostars. In particular, we search for
infall motions, abundance variations, and deviations from spherical
symmetry, using Herschel data from the WISH program.
We used HIFI maps of the 987GHz H2O 202-111 emission to measure
the sizes and shapes of 19 high-mass protostellar envelopes. To
identify infall, we used HIFI spectra of the optically thin C18O 9-8
and H218O 111-000 lines. The high-J C18O line traces the
warm central material and redshifted H218O 111-000 absorption
indicates material falling onto the warm core. We probe small-scale
chemical differentiation by comparing H2O 752 and 987GHz spectra
with those of H218O.
Our measured radii of the central part of the H2O 202-111
emission are 30-40% larger than the predictions from spherical
envelope models, and axis ratios are <2, which we consider good
agreement. For 11 of the 19 sources, we find a significant redshift of
the H218O 111-000 line relative to C18O 9-8. The inferred
infall velocities are 0.6-3.2km/s, and estimated mass inflow rates
range from 7x10-5 to 2x10-2M☉/yr. The highest mass inflow
rates seem to occur toward the sources with the highest masses, and
possibly the youngest ages. The other sources show either expanding
motions or H218O lines in emission. The H218O 111-000 line
profiles are remarkably similar to the differences between the H2O
202-111 and 211-202 profiles, suggesting that the H218O
line and the H2O 202-111 absorption originate just inside the
radius where water evaporates from grains, typically 1000-5000au from
the center. In some sources, the H218O line is detectable in the
outflow, where no C18O emission is seen.
Together, the H218O absorption and C18O emission profiles show
that the water abundance around high-mass protostars has at least
three levels: low in the cool outer envelope, high within the 100K
radius, and very high in the outflowing gas. Thus, despite the small
regions, the combination of lines presented in this work reveals
systematic inflows and chemical information about the outflows.
Description:
Herschel/HIFI spectra and maps of H2O lines toward 19 regions of
highmass star formation
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 102 19 Source sample
list.dat 203 94 List of fits spectra and datacubes
fits/* . 94 Individual fits files
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See also:
J/ApJ/720/1055 : VBLA observations of W51 Main/South (Sato+, 2010)
J/A+A/579/A91 : ATLASGAL inner Galaxy massive cold dust clumps (Wienen+, 2015)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 24 A24 --- Type Type
25 A1 --- n_Type [*] Note on Type (1)
27- 40 A14 --- Source Source name
42- 43 I2 h RAh Right ascension (J2000.0)
45- 46 I2 min RAm Right ascension (J2000.0)
48- 51 F4.1 s RAs Right ascension (J2000.0)
53 A1 --- DE- Declination sign (J2000)
54- 55 I2 deg DEd Declination (J2000)
57- 58 I2 arcmin DEm Declination (J2000)
60- 61 I2 arcsec DEs Declination (J2000)
63- 68 E6.2 Lsun Lbol Bolometric luminosity
70- 72 F3.1 kpc Dist Distance
74- 77 I4 Msun Menv Envelope mass
79 I1 --- r_Dist Distance reference (2)
81-102 A22 --- SName Simbad name
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Note (1): *: High-Mass Protostellar Objects.
Note (2): References as follows:
1 = van der Tak et al. (2013A&A...554A..83V 2013A&A...554A..83V)
2 = Zhang et al. (2014ApJ...781...89Z 2014ApJ...781...89Z)
3 = Sanna et al. (2014ApJ...781..108S 2014ApJ...781..108S)
4 = Kurayama et al. (2011); Xu et al. (2016ApJ...819..117X 2016ApJ...819..117X)
5 = Wu et al. (2014A&A...566A..17W 2014A&A...566A..17W)
6 = Wienen et al. (2015, Cat. J/A+A/579/A91)
7 = Sato et al. (2010, Cat. J/ApJ/720/1055)
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 23 I4 --- Nx Number of pixels along X-axis
25- 26 I2 --- Ny ? Number of pixels along Y-axis
for the datacubes
28- 31 I4 --- Nz ? Number of slices for the datacubes
33- 58 A26 "datime" Obs.date Observation date
60- 71 E12.6 Hz bFreq ? Lower value of frequency interval
for spectra
73- 83 E11.6 Hz BFreq ? Upper value of frequency interval
for spectra
85- 90 I6 Hz dFreq ? Frequency resolution for spectra
92-100 F9.4 m/s bVel ? Lower value of velocity interval
for datacubes
102-109 F8.4 m/s BVel ? Upper value of velocity interval
for datacubes
111-118 F8.6 m/s dVel ? Velocity resolution for datacubes
120-123 I4 Kibyte size Size of FITS file
125-153 A29 --- FileName Name of FITS file, in subdirectory fits
155-203 A49 --- Title Title of the FITS file
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Acknowledgements:
Floris van der Tak, vdtak(at)sron.nl
(End) Patricia Vannier [CDS] 03-Jun-2019