J/A+A/640/A75 SOLIS. X. NGC 1333 IRAS 4A images (De Simone+, 2020)
Seeds of Life in Space (SOLIS).
X. Interstellar Complex Organic Molecules in the NGC 1333 IRAS 4A outflows.
De Simone M., Codella C., Ceccarelli C., Lopez-Sepulcre A., Dehghanfar A.,
Neri R., Balucani N., Caselli P., Favre C., Fontani F., Lefloch B.,
Ospina-Zamudio J., Pineda J.E., Taquet V.
<Astron. Astrophys. 640, A75 (2020)>
=2020A&A...640A..75D 2020A&A...640A..75D (SIMBAD/NED BibCode)
ADC_Keywords: YSOs ; Interstellar medium ; Interferometry
Keywords: astrochemistry - instrumentation: interferometers - stars: formation -
ISM: jets and outflows - ISM: molecules -
ISM: individual objects: IRAS 4A
Abstract:
The interstellar complex organic molecules (iCOMs) are C-bearing
molecules containing at least six atoms; two main proposals for their
formation are suggested: a direct formation in the icy mantle of the
dust grains and formation through the reaction in gas phase of
released grain mantle species. The shocked gas along outflows driven
by low-mass protostars is a unique environment to study how the iCOMs
can be formed as the composition of the dust mantles is sputtered into
the gas phase.
The chemical richness in shocked material associated with low-mass
protostellar outflows has been so far studied in the prototypical
L1157 blue-shifted outflow to investigate the iCOM formation routes.
To understand whether the case of L1157-B1 is unique, we imaged and
studied the IRAS 4A outflows in the NGC 1333 star forming region.
We used the NOrthern Extended Millimeter Array (NOEMA) interferometer
as part of the IRAM Seeds Of Life in Space (SOLIS) Large Program to
image the large-scale bipolar outflows driven by the IRAS 4A system in
the 3 mm band, and we compared the observation with the GRAINOBLE+
astrochemical model.
We report the first detection, in the IRAS 4A outflows, of several
iCOMs: six lines of methanol (CH3OH), eight of acetaldehyde
(CH3CHO), one of formamide (NH2CHO), and four of dimethyl ether
(CH3OCH3), all sampling upper excitation energy up to 30K. We
found a significant chemical differentiation between the southeast
outflow driven by the IRAS 4A1 protostar, showing a richer molecular
content, and the north-southwest one driven by the IRAS 4A2 hot
corino. The CH3OH/CH3CHO abundance ratio is lower by a factor of 4
in the former; furthermore, the ratio in the IRAS 4A outflows is lower
by a factor of 10 with respect to the values found in different hot
corinos.
After L1157-B1, the IRAS 4A outflow is now the second outflow to show
an evident chemical complexity. Given that CH3OH is a grain surface
species, the astrochemical gas-phase model run with GRAINOBLE+
reproduced our observation assuming that acetaldehyde is formed mainly
through the gas-phase reaction of the ethyl radical (CH3CH2) and
atomic oxygen. Furthermore, the chemical differentiation between the
two outflows suggests that the IRAS 4A1 outflow is likely younger than
that of the IRAS 4A2. Further investigation is needed to constrain the
age of the outflow. In addition, observation of even younger shocks
are necessary. In order to provide strong constraints on the CH3CHO
formation mechanisms it would be interesting to observe CH3CH2,
but given that its frequencies are not known, future spectroscopic
studies on this species are needed.
Description:
IRAS 4A was observed with the IRAM/NOEMA interferometer
during several tracks in June and September 2016. Two frequency setups
were used, called 1 and 3 in Ceccarelli et al. (2017ApJ...850..176C 2017ApJ...850..176C,
Table 4), centered at 82 and 97GHz, respectively. The array was used
in configurations D and C with baselines from 15m to 304m for Setup
3 and from 16m to 240m for Setup 1.
Objects:
--------------------------------------------------------------
RA (2000) DE Designation(s)
--------------------------------------------------------------
03 29 10.5 +31 13 30.9 NGC 1333 IRAS 4A = [JCC87] IRAS 4A
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 240 4 List of fits files
fits/* . 4 Individual fits files
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See also:
J/A+A/605/A57 : SOLIS. I. OMC2-FIR4 HC3N and HC5N images (Fontani+, 2017)
J/A+A/605/L3 : SOLIS. II. L1157-B1 NH2CHO image (Codella+, 2017)
J/A+A/640/A74 : SOLIS. VIII. L1157-B1 spectra (Spezzano+, 2020)
J/A+A/558/A58 : NGC 1333-IRAS 4A C18O, NO and O2 spectra (Yildiz+, 2013)
J/A+A/568/A125 : NGC 1333 IRAS 4A H2O observations (Santangelo+, 2014)
J/A+A/606/A121 : NGC 1333 IRAS 4A ALMA and PdBI maps (Lopez-Sepulcre+, 2017)
Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 22 I3 --- Nx Number of pixels along X-axis
24- 26 I3 --- Ny Number of pixels along Y-axis
28- 31 I4 Kibyte size Size of FITS file
33- 54 A22 --- FileName Name of FITS file, in subdirectory fits
56-240 A185 --- Title Title of the FITS file
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Acknowledgements:
Marta De Simone, marta.desimone(at)univ-grenoble-alpes.fr
References:
Fontani et al., Paper I 2017A&A...605A..57F 2017A&A...605A..57F, Cat. J/A+A/605/A57
Codella et al., Paper II 2017A&A...605L...3C 2017A&A...605L...3C, Cat. J/A+A/605/L3
Ceccarelli et al., 2017ApJ...850..176C 2017ApJ...850..176C
Punanova et al., Paper III 2018ApJ...855..112P 2018ApJ...855..112P
Favre et al., Paper IV 2018ApJ...859..136F 2018ApJ...859..136F
Codella et al., Paper V 2020A&A...635A..17C 2020A&A...635A..17C
Favre et al., Paper VII 2020A&A...635A.189F 2020A&A...635A.189F
Spezzano et al., Paper VIII 2020A&A...640A..74S 2020A&A...640A..74S, Cat. J/A+A/640/A74
Feng et al., Paper IX 2020ApJ...896...37F 2020ApJ...896...37F
(End) Patricia Vannier [CDS] 10-Aug-2020