J/A+A/579/A80 Star-forming regions deuteration (Gerner+, 2015)
Chemical evolution in the early phases of massive star formation.
II. Deuteration.
Gerner T., Shirley Y.L., Beuther H., Semenov D., Linz H., Albertsson T.,
Henning T.
<Astron. Astrophys., 579, A80-80 (2015)>
=2015A&A...579A..80G 2015A&A...579A..80G (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; Spectroscopy
Keywords: stars: formation - stars: early-type - ISM: molecules - evolution -
astrochemistry
Abstract:
The chemical evolution in high-mass star-forming regions is still
poorly constrained. Studying the evolution of deuterated molecules
allows distinguishing between subsequent stages of high-mass star
formation regions based on the strong temperature dependence of
deuterium isotopic fractionation. We observed a sample of 59 sources
including 19 infrared dark clouds, 20 high-mass protostellar objects,
11 hot molecular cores and 9 ultra-compact HII regions in the (3-2)
transitions of the four deuterated molecules, DCN, DNC, DCO+, and
N2D+ as well as their non-deuterated counterparts. The overall
detection fraction of DCN, DNC, and DCO+ is high and exceeds 50% for
most of the stages. N2D+ was only detected in a few infrared dark
clouds and high-mass protostellar objects. This may be related to
problems in the bandpass at the transition frequency and to low
abundances in the more evolved, warmer stages. We find median D/H
ratios of 0.02 for DCN, 0.005 for DNC, 0.0025 for DCO+, and 0.02 for
N2D+. While the D/H ratios of DNC, DCO+, and N2D+ decrease
with time, DCN/HCN peaks at the hot molecular core stage. We only
found weak correlations of the D/H ratios for N2D+ with the
luminosity of the central source and the FWHM of the line, and no
correlation with the H2 column density. In combination with a
previously observed set of 14 other molecules (Paper I), we fitted the
calculated column densities with an elaborate 1D physico-chemical
model with time-dependent D-chemistry including ortho- and para-H2
states. Good overall fits to the observed data were obtained with the
model. This is one of the first times that observations and modeling
were combined to derive chemically based best-fit models for the
evolution of high-mass star formation including deuteration.
Description:
The sources were taken from Gerner et al. (2014, Cat. J/A+A/563/A97)
and were initially selected from different source lists. The total
sample contains 59 high-mass star-forming regions, consisting of 19
IRDCs and 20 HMPOs as well as 11 HMCs and 9 UCHIIs. The sources were
selected from well-known source catalogs of the literature without
specific selection criteria such as spherical symmetry.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 83 59 Source list showing the position, the distance,
and the evolutionary stage of all high-mass
star-forming regions
tablea2.dat 98 59 Luminosity, H2, DCO+, DCN, DNC, and N2D+
column density and the corresponding error
for each source
tablea3.dat 75 59 HCO+, HCN, HNC, and N2H+ column density
and corresponding error for each source
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See also:
J/A+A/563/A97 : IRAM 30m reduced spectra of 59 sources (Gerner+, 2014)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- Source Source name
13- 14 I2 h RAh Right ascension (J2000)
16- 17 I2 min RAm Right ascension (J2000)
19- 22 F4.1 s RAs Right ascension (J2000)
24 A1 --- DE- Declination sign (J2000)
25- 26 I2 deg DEd Declination (J2000)
28- 29 I2 arcmin DEm Declination (J2000)
31- 32 I2 arcsec DEs Declination (J2000)
34- 40 F7.3 deg GLON Galactic longitude
42- 48 F7.3 deg GLAT Galactic latitude
50- 54 F5.2 kpc Dist Distance (preferred one)
55 A1 --- n_Dist [deh] Note on Dist (1)
57- 61 F5.2 kpc Dist2 ? Alternative distance
62 A1 --- n_Dist2 [fij] Note on Dist2 (1)
64- 68 A5 --- Type Stage of source (4)
70 A1 --- 24um [yn- ] Embedded IRDC 24um point source ? (2)
72 A1 --- 70um [yn- ] Embedded IRDC 70um point source ? (2)
73 A1 --- n_70um [cg] Note on 70um (3)
76- 83 A8 --- Ref Sources of the dust continuum data (5)
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Note (1): Distance notes as follows:
d = For vlsr = 111.3km/s (preferred) or 97.6km/s (alternative)
e = For vlsr = 100.2km/s (preferred) or 52.8km/s (alternative)
f = For vlsr = 94.3km/s (preferred) or 98.4km/s (alternative)
h = Ellsworth-Bowers et al. (2015ApJ...799...29E 2015ApJ...799...29E, Cat. J/ApJ/799/29)
i = For the near (far) kinematic solution
j = Parallactic (kinematic) distance
Note (2): For the IRDCs we indicate whether or not they show embedded 24
or 70µm point sources with y(es) or n(o) (or "-" if there are no data
available).
Note (3): Note on 70um as follows:
c = Very weak emission compared with the background located at the
same position as 24um emission source.
g = No embedded central point source found, a nearby extended source
with emission inside the beam is detected.
Note (4): the four stages are:
IRDC = Infra-Red Cark Cloud stage (densities ≳105cm-3)
HMPO = High-Mass protostellar Object (accreting protostar >8M☉)
HMC = Hot Molecular Core (central source heats the surrounding environment)
UCHII = Ultra-Compact HII region (UV radiation from protostar ionizes the
surrounding gas)
Note (5): Dust continuum data as follows:
ATLASGAL = galactic plane survey ATLASGAL (870um; Schuller et al.,
2009A&A...504..415S 2009A&A...504..415S)
Mambo = IRAM 30m observations with Mambo (1.2mm)
SCUBA = SCUBA Legacy Catalog (850um; Di Francesco et al.,
2008ApJS..175..277D 2008ApJS..175..277D, Cat. J/ApJS/175/277)
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Source Source name
13- 17 F5.2 [Lsun] logL ? Luminosity
18 A1 --- r_logL [a-i] Luminosity reference (2)
20- 26 E7.2 cm-2 NH2 H2 column density (1)
28- 29 A2 --- l_DCO+ [≤ ] Limit flag on DCO+
30- 36 E7.2 cm-2 DCO+ DCO+ column density
38- 44 E7.2 cm-2 e_DCO+ rms uncertainty on DCO+ measured integrated flux
46- 47 A2 --- l_DCN [≤ ] Limit flag on DCN
48- 54 E7.2 cm-2 DCN DCN column density
56- 62 E7.2 cm-2 e_DCN rms uncertainty on DCN measured integrated flux
64- 65 A2 --- l_DNC [≤ ] Limit flag on DNC
66- 72 E7.2 cm-2 DNC ?=- DNC column density
74- 80 E7.2 cm-2 e_DNC rms uncertainty on DNC measured integrated flux
82- 83 A2 --- l_N2D+ [≤ ] Limit flag on N2D+
84- 90 E7.2 cm-2 N2D+ ?=- N2D+ column density
92- 98 E7.2 cm-2 e_N2D+ rms uncertainty on N2D+ measured integrated flux
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Note (1): H2 column density is averaged over a 29"-beam and for all other
molecules over a 30"-beam.
Note (2): References as follows:
a = Ragan et al. (2012A&A...547A..49R 2012A&A...547A..49R, Cat. J/A+A/547/A49)
b = Beuther et al. (2012A&A...538A..11B 2012A&A...538A..11B, Cat. J/A+A/538/A11)
c = Sridharan et al. (2002ApJ...566..931S 2002ApJ...566..931S)
d = Linz et al. (2005A&A...429..903L 2005A&A...429..903L)
e = Churchwell et al. (1990A&AS...83..119C 1990A&AS...83..119C)
f = Chen et al. (2006ApJ...639..975C 2006ApJ...639..975C)
g = Campbell et al. (1995ApJ...454..831C 1995ApJ...454..831C)
h = Beuther et al. (2004ApJ...616L..31B 2004ApJ...616L..31B)
i = Wood & Churchwell (1989ApJ...340..265W 1989ApJ...340..265W)
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Byte-by-byte Description of file: tablea3.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Source Source name
13- 19 E7.2 cm-2 HCO+ HCO+ column density
21- 27 E7.2 cm-2 e_HCO+ rms uncertainty on HCO+ measured integrated flux
and the optical depth τ (1)
29- 35 E7.2 cm-2 HCN ?=- HCN column density
37- 43 E7.2 cm-2 e_HCN ?=- rms uncertainty on HCN measured integrated
flux and the optical depth τ (1)
45- 51 E7.2 cm-2 HNC HNC column density
53- 59 E7.2 cm-2 e_HNC rms uncertainty on HNC measured integrated flux
and the optical depth τ (1)
61- 67 E7.2 cm-2 N2H+ N2H+ column density
69- 75 E7.2 cm-2 e_N2H+ rms uncertainty on N2H+ measured integrated flux
and the optical depth τ (1)
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Note (1): The high uncertainties are in some cases due to high uncertainties in
the determined optical depth.
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References:
Gerner et al., Paper I 2014A&A...563A..97G 2014A&A...563A..97G, Cat. J/A+A/563/A97
(End) Patricia Vannier [CDS] 06-Oct-2015