J/A+A/692/A65 SOMA carbon-chain chemistry of IM protostars (Taniguchi+, 2024)
The SOFIA Massive (SOMA) Star Formation Q-band follow-up.
I. Carbon-chain chemistry of intermediate-mass protostars.
Taniguchi K., Gorai P., Tan C.J., Gomez-Garrido M., Fedriani R.,
Yang Y.-L., Sridharan T.K., Tanaka E.I.K., Saito M., Zhang Y., Morgan L.,
Cosentino G., Law C.-Y.
<Astron. Astrophys. 692, A65 (2024)>
=2024A&A...692A..65T 2024A&A...692A..65T (SIMBAD/NED BibCode)
ADC_Keywords: Protostars ; Radio lines ; Radial velocities ; Abundances
Keywords: astrochemistry - star formation
Abstract:
Evidence for similar chemical characteristics around low- and
high-mass protostars has been found: in particular, a variety of
carbon-chain species and complex organic molecules (COMs) are formed
around them. On the other hand, the chemical compositions around
intermediate-mass (IM) protostars (2M☉<m*<8M☉) protostars
have not been studied with large samples. In particular, it is unclear
the extent to which carbon-chain species are formed around them.
We aim to obtain the chemical compositions, particularly focusing on
carbon-chain species, towards a sample of IM protostars. Another
purpose is deriving the rotational temperatures of HC5N to confirm
whether carbon-chain species are formed in the warm gas around these
stars.
We have conducted Q-band (31.5-50GHz) line survey observations towards
eleven mainly intermediate-mass protostars with the Yebes 40m radio
telescope. The target protostars were selected from a sub-sample of
the source list of the SOFIA Massive (SOMA) Star Formation project.
Assuming local thermodynamic equilibrium (LTE), we have derived column
densities of the detected molecules and rotational temperatures of
HC5N and CH3OH.
Nine carbon-chain species (HC3N, HC5N, C3H, C4H,
linear-H2CCC, cyclic-C3H2, CCS, C3S, and CH3CCH), three COMs
(CH3OH, CH3CHO, and CH3CN), H2CCO, HNCO, and four simple
sulfur (S)-bearing species (13CS, C34S, HCS+, H2CS) have been
detected. The rotational temperatures of HC5N are derived to be
∼20-30K in three IM protostars (Cepheus E, HH288, and IRAS
20293+3952). The rotational temperatures of CH3OH are derived in
five IM sources and found to be similar to those of HC5N.
The rotational temperatures of HC5N around the three IM protostars
are very similar compared to those around low- and high-mass protostars.
These results indicate that carbon-chain molecules are formed in
lukewarm (∼20-30K) gas around the IM protostars by the Warm
Carbon-Chain Chemistry (WCCC) process. Thus, carbon-chain formation
occurs ubiquitously in the warm gas around protostars across a wide
range of stellar masses. Carbon-chain molecules and COMs coexist
around most of the target IM protostars, which is similar to the
situation in low- and high-mass protostars. In summary, the chemical
characteristics around protostars are common in the low-,
intermediate- and high-mass regimes.
Description:
We conducted Q-band (31.5-50GHz) line survey observations toward 11
mainly IM protostars with the Yebes 40m radio telescope. The target
protostars were selected from a subsample of the source list of the
SOFIA Massive Star Formation project.
Table A.2 summarizes the column density of each species and each
source in unit of cm-2.
Table A.3 summarizes full width half maximum and systemic velocity of
each source in unit of km/s.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
sources.dat 48 11 List of studied sources
tablea2.dat 201 26 Summary of column densities
tablea3.dat 261 26 Summary of line widths and centroid velocity
list.dat 122 11 List of fits spectra
fits/* . 11 Individual fits spectra
--------------------------------------------------------------------------------
Byte-by-byte Description of file: sources.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 A18 --- Name Source name
20- 21 I2 h RAh Right ascension (J2000)
23- 24 I2 min RAm Right ascension (J2000)
26- 29 F4.1 s RAs Right ascension (J2000)
31 A1 --- DE- Declination sign (J2000)
32- 33 I2 deg DEd Declination (J2000)
35- 36 I2 arcmin DEm Declination (J2000)
38- 41 F4.1 arcsec DEs Declination (J2000)
43- 48 A6 --- SName Short name used in tables A2 and A3
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Species Species
12- 17 A6 --- n_Species Note on Species (G1)
19 A1 --- l_NCepE Limit flag on NCepE
20- 26 E7.3 cm-2 NCepE ?=- Cepheus E column density of Species
28- 34 E7.3 cm-2 e_NCepE ? Cepheus E column density of Species error
35 A1 --- n_NCepE [a] Note on NCepE (1)
37- 43 E7.3 cm-2 NL1206 ?=- L1206 column density of Species
45- 51 E7.3 cm-2 e_NL1206 ? L1206 column density of Species error
52 A1 --- n_NL1206 [a] Note on NL1206
54- 60 E7.3 cm-2 NHH288 ?=- HH288 column density of Species
62- 68 E7.3 cm-2 e_NHH288 ? HH288 column density of Species error
69 A1 --- n_NHH288 [a] Note on NHH288 (1)
71- 77 E7.3 cm-2 NI00420 ?=- IRAS 00420+5530 column density of Species
79- 85 E7.3 cm-2 e_NI00420 ? IRAS 00420+5530 column density of Species error
87- 93 E7.3 cm-2 NI20343 ?=- IRAS 20343+4129 S1 column density of Species
95-101 E7.3 cm-2 e_NI20343 ? IRAS 20343+4129 S1 column density of Species
error
103 A1 --- l_NI00259 Limit flag on NI00259
104-110 E7.3 cm-2 NI00259 ?=- IRAS 00259+5625 column density of Species
112-118 E7.3 cm-2 e_NI00259 ? IRAS 00259+5625 column density of Species error
120-126 E7.3 cm-2 NI05380 ?=- IRAS 05380+2020 column density of Species
128-134 E7.3 cm-2 e_NI05380 ? IRAS 05380+2020 column density of Species error
136-142 E7.3 cm-2 NI20293 ?=- IRAS 20293+3952 column density of Species
144-150 E7.3 cm-2 e_NI20293 ? IRAS 20293+3952 column density of Species error
151 A1 --- n_NI20293 [b] Note on NI20293 (1)
153-159 E7.3 cm-2 NI21307 ?=- IRAS 21307+5049 column density of Species
161-167 E7.3 cm-2 e_NI21307 ? IRAS 21307+5049 column density of Species error
170-176 E7.3 cm-2 NI22198 ?=- IRAS 22198+6336 column density of Species
178-184 E7.3 cm-2 e_NI22198 ? IRAS 22198+6336 column density of Species error
186-192 E7.3 cm-2 NI23385 ?=- IRAS 23385+6053 column density of Species
194-200 E7.3 cm-2 e_NI23385 ? IRAS 23385+6053 column density of Species error
201 A1 --- n_NI23385 [b] Note on NI23385 (1)
--------------------------------------------------------------------------------
Note (1): Notes as follows:
a = The column densities are derived by the rotational diagram method
b = The 2nd velocity component
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Species Species
12- 17 A6 --- n_Species Note on Species (G1)
20- 23 F4.2 km/s FWHMCepE ?=- Cepheus E FWHM of Species
25- 28 F4.2 km/s e_FWHMCepE ? Cepheus E FWHM of Species
standard deviation error
30- 35 F6.2 km/s VlsrCepE ?=- Cepheus E LSR velocity of Species
37- 40 F4.2 km/s e_VlsrCepE ? Cepheus E LSR velocity of Species
standard deviation error
42- 45 F4.2 km/s FWHML1206 ?=- L1206 FWHM of Species
47- 50 F4.2 km/s e_FWHML1206 ? L1206 FWHM of Species
standard deviation error
52- 57 F6.2 km/s VlsrL1206 ?=- L1206 LSR velocity of Species
59- 62 F4.2 km/s e_VlsrL1206 ? L1206 LSR velocity of Species
standard deviation error
64- 67 F4.2 km/s FWHMHH288 ?=- HH288 FWHM of Species
69- 72 F4.2 km/s e_FWHMHH288 ? HH288 FWHM of Species
standard deviation error
74- 79 F6.2 km/s VlsrHH288 ?=- HH288 LSR velocity of Species
81- 84 F4.2 km/s e_VlsrHH288 ? HH288 LSR velocity of Species
standard deviation error
86- 89 F4.2 km/s FWHMI00420 ?=- IRAS 00420+5530 FWHM of Species
91- 94 F4.2 km/s e_FWHMI00420 ? IRAS 00420+5530 FWHM of Species
standard deviation error
96-101 F6.2 km/s VlsrI00420 ?=- IRAS 00420+5530 LSR velocity of Species
103-106 F4.2 km/s e_VlsrI00420 ? IRAS 00420+5530 LSR velocity of Species
standard deviation error
108-111 F4.2 km/s FWHMI20343 ?=- IRAS 20343+4129 S1 FWHM of Species
113-116 F4.2 km/s e_FWHMI20343 ? IRAS 20343+4129 S1 FWHM of Species
standard deviation error
118-122 F5.2 km/s VlsrI20343 ?=- IRAS 20343+4129 S1 LSR velocity
of Species
124-127 F4.2 km/s e_VlsrI20343 ? IRAS 20343+4129 S1 LSR velocity of Species
standard deviation error
129-132 F4.2 km/s FWHMI00259 ?=- IRAS 00259+5625 FWHM of Species
134-137 F4.2 km/s e_FWHMI00259 ? IRAS 00259+5625 FWHM of Species
standard deviation error
139-144 F6.2 km/s VlsrI00259 ?=- IRAS 00259+5625 LSR velocity of Species
146-149 F4.2 km/s e_VlsrI00259 ? IRAS 00259+5625 LSR velocity of Species
standard deviation error
151-154 F4.2 km/s FWHMI05380 ?=- IRAS 05380+2020 FWHM of Species
156-159 F4.2 km/s e_FWHMI05380 ? IRAS 05380+2020 FWHM of Species
standard deviation error
161-164 F4.2 km/s VlsrI05380 ?=- IRAS 05380+2020 LSR velocity of Species
166-169 F4.2 km/s e_VlsrI05380 ? IRAS 05380+2020 LSR velocity of Species
standard deviation error
171-175 F5.3 km/s FWHMI20293 ?=- IRAS 20293+3952 FWHM of Species
177-181 F5.3 km/s e_FWHMI20293 ? IRAS 20293+3952 FWHM of Species
standard deviation error
182 A1 --- n_FWHMI20293 [a] Note on FWHMI20293 (1)
184-187 F4.2 km/s VlsrI20293 ?=- IRAS 20293+3952 LSR velocity of Species
189-192 F4.2 km/s e_VlsrI20293 ? IRAS 20293+3952 LSR velocity of Species
standard deviation error
193 A1 --- n_VlsrI20293 [a] note on VlsrI20293 (1)
195-198 F4.2 km/s FWHMI21307 ?=- IRAS 21307+5049 FWHM of Species
200-203 F4.2 km/s e_FWHMI21307 ? IRAS 21307+5049 FWHM of Species
standard deviation error
205-210 F6.2 km/s VlsrI21307 ?=- IRAS 21307+5049 LSR velocity of Species
212-215 F4.2 km/s e_VlsrI21307 ? IRAS 21307+5049 LSR velocity of Species
standard deviation error
217-220 F4.2 km/s FWHMI22198 ?=- IRAS 22198+6336 FWHM of Species
222-225 F4.2 km/s e_FWHMI22198 ? IRAS 22198+6336 FWHM of Species
standard deviation error
227-232 F6.2 km/s VlsrI22198 ?=- IRAS 22198+6336 LSR velocity of Species
234-237 F4.2 km/s e_VlsrI22198 ? IRAS 22198+6336 LSR velocity of Species
standard deviation error
239-242 F4.2 km/s FWHMI23385 ?=- IRAS 23385+6053 FWHM of Species
244-247 F4.2 km/s e_FWHMI23385 ? IRAS 23385+6053 FWHM of Species
standard deviation error
248 A1 --- n_FWHMI23385 [a] note on FWHMI23385
250-255 F6.2 km/s VlsrI23385 ?=- IRAS 23385+6053 LSR velocity of Species
257-260 F4.2 km/s e_VlsrI23385 ? IRAS 23385+6053 LSR velocity of Species
standard deviation error
261 A1 --- n_VlsrI23385 [a] Note on VlsrI23385
--------------------------------------------------------------------------------
Note (1): Note as follows:
a = The 2nd velocity component
--------------------------------------------------------------------------------
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
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- 25 I6 --- Nx Number of pixels along X-axis
27- 49 A23 "datime" Obs.date Observation date
51- 58 F8.5 GHz bFreq Lower value of frequency interval
60- 66 F7.4 GHz BFreq Upper value of frequency interval
68- 74 F7.1 Hz dFreq Frequency resolution
76- 79 I4 Kibyte size Size of FITS file
81- 94 A14 --- FileName Name of FITS file, in subdirectory fits
96-122 A27 --- Title Title of the FITS file
--------------------------------------------------------------------------------
Global notes:
Note (G1): Numbers in parentheses indicate the standard deviation error.
"high" and "low" mean the column densities derived by fixed excitation
temperatures at 20K and 6.5K, respectively.
Without these indications, we fixed the excitation temperatures at 20K.
--------------------------------------------------------------------------------
Acknowledgements:
Kotimi Taniguchi, kotomi.taniguchi(at)nao.ac.jp
(End) Patricia Vannier [CDS] 07-Nov-2024