J/A+A/575/A87 Deuteration in massive star formation process (Fontani+, 2015)
Deuteration and evolution in the massive star formation process.
The role of surface chemistry.
Fontani F., Busquet G., Palau A., Caselli P. Sanchez-Monge A., Tan J.C.,
Audard M.
<Astron. Astrophys. 575, A87 (2015)>
=2015A&A...575A..87F 2015A&A...575A..87F
ADC_Keywords: Interstellar medium ; Spectroscopy ; Molecular clouds
Keywords: stars: formation - molecular data - submillimeter: ISM -
ISM: molecules
Abstract:
An ever growing number of observational and theoretical evidence
suggests that the deuterated fraction (column density ratio between
a species containing D and its hydrogenated counterpart, Dfrac) is
an evolutionary indicator both in the low- and the high-mass star
formation process. However, the role of surface chemistry in these
studies has not been quantified from an observational point of view.
In order to compare how the deuterated fractions of species formed
only in the gas and partially or uniquely on grain surfaces evolve
with time, we observed rotational transitions of CH3OH, 13CH3OH,
CH2DOH, CH3OD at 3 and 1.3mm, and of NH2D at 3mm with the
IRAM-30m telescope, and the inversion transitions (1,1) and (2,2) of
NH3 with the GBT, towards most of the cores already observed by
Fontani et al. (2011A&A...529L...7F 2011A&A...529L...7F, 2014MNRAS.440..448F 2014MNRAS.440..448F) in N2H+,
N2D+, HNC, DNC. NH2D is detected in all but two cores,
regardless of the evolutionary stage. Dfrac(NH3) is on average above
0.1, and does not change significantly from the earliest to the most
evolved phases, although the highest average value is found in the
protostellar phase (∼0.3). Few lines of CH2DOH and CH3OD are
clearly detected, and only towards protostellar cores or externally
heated starless cores. This work clearly confirms an expected
different evolutionary trend of the species formed exclusively in the
gas (N2D+ and N2H+) and those formed partially (NH2D and
NH3) or totally (CH2DOH and CH3OH) on grain mantles. The study
also reinforces the idea that Dfrac(N2H+) is the best tracer of
massive starless cores, while high values of Dfrac(CH3OH) seem
rather good tracers of the early protostellar phases, at which the
evaporation/sputtering of the grain mantles is most efficient.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 99 28 List of the observed sources
tableb1.dat 154 219 Transitions of CH3OH,13CH3OH, CH2DOH and
CH3OD detected at 3mm, and line parameters
derived from Gaussian fits
tableb2.dat 154 90 Transitions of CH3OH, 13CH3OH, CH2DOH and
CH3OD detected at 1mm, and line parameters
derived from Gaussian fits
spectra.dat 96 28 Summary of NH2D spectra (in "sp" subdirectory)
sp/* . 2 Individual FITS spectra files
img/* . 40 Individual Boltzmann plots (rotation diagrams)
derived from CH3OH and 13CH3OH for all cores
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- Type Type of source (G1)
8- 19 A12 --- Name Source name
21 A1 --- n_Name [aw] Note on source (1)
23- 24 I2 h RAh Right ascension (J2000)
26- 27 I2 min RAm Right ascension (J2000)
29- 32 F4.1 s RAs Right ascension (J2000)
34 A1 --- DE- Declination sign (J2000)
35- 36 I2 deg DEd Declination (J2000)
38- 39 I2 arcmin DEm Declination (J2000)
41- 42 I2 arcsec DEs Declination (J2000)
44- 48 F5.1 km/s VLSR LSR velocity (2)
50- 53 A4 --- OName Other designation (3)
55- 87 A33 --- SName Simbad name
89- 99 A11 --- Source Names as in FITS files (added by CDS)
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Note (1): Notes as follows:
a = Source not included in paper I (Fontani et al., 2011A&A...529L...7F 2011A&A...529L...7F),
selected from Butler & Tan (2014ApJ...782L..30B 2014ApJ...782L..30B).
See also Butler et al. (2014ApJ...782L..30B 2014ApJ...782L..30B)
w = "warm" (T≥20K) HMSCs externally heated (see paper I (Fontani et al.
2011A&A...529L...7F 2011A&A...529L...7F)).
Note (2): Velocity at which we centred the spectra, corresponding to the
systemic velocity. More information (e.g. source distances, bolometric
luminosities of the associated star forming regions, reference papers)
are given in Table 1 of paper I (Fontani et al., 2011A&A...529L...7F 2011A&A...529L...7F).
Note (3): designations in Simbad:
MM2 = [RJS2006] MSXDC G034.77-00.55 MM2
MM7 = [RJS2006] MSXDC G034.77-00.55 MM7
MM8 = [RJS2006] MSXDC G034.77-00.55 MM8
MM9 = [RJS2006] MSXDC G028.37+00.07 MM9
MM11 = [RJS2006] MSXDC G028.37+00.07 MM11
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Byte-by-byte Description of file: tableb1.dat tableb2.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Type Type of source (G1)
9- 21 A13 --- Name Source name
23- 31 F9.2 MHz Freq [89275/223423]? Frequency
33- 62 A30 --- Trans Transition
65- 76 E12.6 K.km/s Sint ? Line Integrated intensity ∫TMB.dv
77- 81 F5.3 K.km/s e_Sint [0.002/2]? rms uncertainty on Sint
85- 89 F5.3 km/s DV [0.4/8]? Full width at half maximum ΔV
91- 97 F7.3 km/s e_DV ? rms uncertainty on DeltaV
100-110 E11.6 K Tpk [0/4]? Main beam temperature at line peak
111 A1 --- u_Tpk [ab] problems in Tpeak estimation (1)
113-123 A11 --- Source Name as in FITS files (added by CDS)
125-154 A30 --- bzFile Name of rotation diagram (Fig.2)
in subdirectory "img" (added by CDS)
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Note (1): Note as follows:
a = tentative detection in between 2 and 3σ rms
b = partially blended with (CH2OH)2 (ethylene-glycol)
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Byte-by-byte Description of file: spectra.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Source Source name
14- 21 F8.4 deg RAdeg Right ascension (J2000)
23- 30 F8.4 deg DEdeg Declination (J2000)
32- 36 F5.1 km/s Vel Velocity (LSR) of reference channel
38 A1 --- --- [o]
40- 42 I3 --- Sc.o Scan identification number of ortho spectrum
44- 62 A19 "datime" Obs.o Observation date and time of ortho spectrum
65- 66 I2 --- Seq.o [1/28] Sequence number of ortho-NH2D spectrum
(in file sp/NH2Dortho.fits)
68 A1 --- --- [p]
70- 72 I3 --- Sc.p ? Scan identification number of ortho spectrum
74- 92 A19 "datime" Obs.p ? Observation date and time of para spectrum
95- 96 I2 --- Seq.p [1/28]? Sequence number of para-NH2D spectrum
(in file sp/NH2Dpara.fits)
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Global notes:
Note (G1): Types are:
HMSC = high-mass starless core
HMPO = high-mass protostellar object
UC HII = ultracompact HII region
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Acknowledgements:
Francesco Fontani, fontani(at)arcetri.astro.it
(End) Francesco Fontani [INAF-OAA, Italy], Patricia Vannier [CDS] 17-Nov-2014