J/A+A/657/A136 OMC-2 FIR4 fits images (Evans+, 2022)
SOLIS. XIII. Nitrogen fractionation towards the protocluster OMC-2 FIR4.
Evans L., Fontani F., Vastel C., Ceccarelli C., Caselli P.,
Lopez-Sepulcre A., Neri R., Alves F., Chahine L., Favre C., Lattanzi V.
<Astron. Astrophys. 657, A136 (2022)>
=2022A&A...657A.136E 2022A&A...657A.136E (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Infrared sources
Keywords: stars: formation - ISM: clouds - ISM: molecules
Abstract:
Isotopic fractionation is an important tool for investigating the
chemical history of our Solar System. In particular, the isotopic
fraction of nitrogen (14N/15N) is lower in comets and other
pristine Solar System bodies with respect to the value measured for
the protosolar nebula, suggesting a local chemical enrichment of 15N
during the formation of the Solar System. Therefore, interferometric
studies of nitrogen fractionation in Solar System precursors are
needed for us to obtain clues about our astrochemical origins. In this
work we have investigated the variation in the 14N/15N ratio in
one of the closest analogues of the environment in which the Solar
System was born: the protocluster OMC-2 FIR4. We present the first
comparison at high angular resolution between HCN and N2H+ using
interferometric data. We analysed observations of the HCN
isotopologues H13CN and HC15N in the OMC-2 FIR4 protocluster.
Specifically, we observed the transitions H13CN (1-0) and HC15N
(1-0) with the NOrthern Extended Millimeter Array (NOEMA) within the
context of the IRAM Seeds Of Life In Space (SOLIS) Large Program. We
combined our results with analysis of archival data obtained with the
Atacama Large Millimeter Array (ALMA) of N2H+ and its 15N
isotopologues. Our results show a small regional variation in the
14N/15N ratio for HCN, from ∼250 to 500. The ratios in the central
regions of FIR4, where the candidate protostars are located, are
largely consistent with one another and within that range (∼300). They
also show little variation from the part of the protocluster known to
harbour a high cosmic-ray ionisation rate to the portion with a lower
rate. We also found a small variation in the 14N/15N ratio of
N2H+ across different regions, from ∼200 to ∼400. These results
suggest that local changes in the physical parameters occurring on the
small linear scales probed by our observations in the protocluster do
not seem to affect the 14N/15N ratio in either HCN or N2H+ and
hence that this is independent of the molecule used. Moreover, the
high level of irradiation due to cosmic rays does not affect the N
fractionation either.
Description:
Within the context of the Large Program Seeds Of Life In Space
(SOLIS), interferometric data of H13CN and HC15N emission was
obtained using the IRAM NOEMA interferometer in an attempt to probe
the 14N/15N ratio in HCN in the proto-solar analogue OMC-2 FIR4 at
scales not previously studied. In addition, archival ALMA observations
of N2H+ and its two 15N-isotopologues (15NNH+ and
N15NH+) towards OMC-2 FIR4 were also utilised to obtain the
14N/15N ratio in N2H+ in order to compare this to that of HCN;
thus we have the first interferometric study of two of the most
abundant N-bearing species towards a proto-solar analogue.
Objects:
------------------------------------------------------------
RA (2000) DE Designation(s)
------------------------------------------------------------
05 35 26.79 -05 10 08.8 [TMV2019] OMC-2 FIR4 ALMA1
------------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
list.dat 258 2 List of fits files
fits/* . 2 Individual fits files
--------------------------------------------------------------------------------
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/640/A75 : SOLIS. X. NGC 1333 IRAS 4A images (De Simone+, 2020)
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- 23 I4 --- Nx Number of pixels along X-axis
25- 28 I4 --- Ny Number of pixels along Y-axis
30- 34 I5 m/s VRAD Radial velocity
36- 39 I4 Kibyte size Size of FITS file
41- 59 A19 --- FileName Name of FITS file, in subdirectory fits
61-258 A198 --- Title Title of the FITS file
--------------------------------------------------------------------------------
Acknowledgements:
Lucy Evans, levans(at)irap.omp.eu
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
De Simone et al., Paper X 2020A&A...640A..75D 2020A&A...640A..75D, Cat. J/A+A/640/A75
Benedettini et al., Paper XI 2021A&A...645A..91B 2021A&A...645A..91B
(End) Lucy Evans [IRAP, France & INAF, Italy] Patricia Vannier [CDS] 29-Oct-2021