J/A+A/687/A195 IRAM-30m spectrum observed toward L1551 IRS 5 (Marchand+, 2024)
Chemical inventory of the envelope of the Class I protostar L1551 IRS 5.
Marchand P., Coutens A., Scigliuto J., Cruz-Saenz de Miera F., Andreu A.,
Loison J.-C., Kospal A., Abraham P.
<Astron. Astrophys. 687, A195 (2024)>
=2024A&A...687A.195M 2024A&A...687A.195M (SIMBAD/NED BibCode)
ADC_Keywords: Protostars ; Spectra, millimetric/submm
Keywords: astrochemistry - stars: formation - ISM: molecules
Abstract:
Episodic accretion in protostars leads to luminosity outbursts that
end up heating their surroundings. This rise in temperature pushes the
snow lines back, enabling the desorption of chemical species from dust
grain surfaces, which may significantly alter the chemical history of
the accreting envelope. However, a limited number of extensive
chemical surveys of eruptive young stars have been performed thus far.
In the present study, we carry out a large spectral survey of the
binary Class I protostar L1551 IRS 5, known to be a FUor-like object,
in the 3mm and 2mm bands with the IRAM-30m telescope. As a result, we
detected more than 400 molecular lines. The source displays a great
chemical richness with the detection of 75 species, including
isotopologues. Among these species, there are 13 hydrocarbons, 25
N-bearing species, 30 O-bearing species, 15 S-bearing species, 12
deuterated molecules, and a total of 10 complex organic molecules
(l-C4H2, CH3CCH, CH2DCCH, CH3CHO, CH3CN, CH3OCH3 ,
CH3OCHO, CH3OH, CH2DOH, and HC5N). With the help of local
thermodynamic equilibrium (LTE) and non-LTE models, we determined the
column densities of most molecules as well as excitation and kinetic
temperatures. While most of those molecules trace the cold envelope
(<20K), the OCS and CH3OH emission arise from the warm (>100K)
innermost (<2arcsec) regions. We compared the chemical inventory of
L1551 IRS 5 and its column density ratios, including isotopic ratios,
with other protostellar sources. A broad chemical diversity is seen
among Class I objects. More observations with both single-dish
telescopes and interferometers are needed to characterize the
diversity in a larger sample of protostars, while more astrochemical
models would help explain this diversity, in addition to the impact of
luminosity outbursts on the chemistry of protostellar envelopes.
Description:
Spectrum observed toward the Class I protostar L1551 IRS 5, using the
IRAM-30m telescope in the frequency ranges [71.75-115.75]GHz,
[135.25-143.25]GHz, [143.389-147.029]GHz and [151.25-159.25]GHz.
The noise level in those ranges are ∼5mK, ∼15.7mK, ∼17mK, and ∼5mK,
respectively. The data is the reduced spectrum after substraction of
the baseline and averaging.
Objects:
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RA (2000) DE Designation(s)
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04 31 34.161 +18 08 04.722 L1551 IRS 5 = IRAS 04287+1801
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
spectrum.dat 25 329686 Spectrum observed toward L1551 IRS 5 with
IRAM-30m
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See also:
J/A+A/659/A67 : IRAM spectra of 4 Class I sources (Mercimek+, 2022)
J/A+A/677/A97 : L1551 IRS 5 and NE jets radio images (Feeney-Johansson+, 2023)
Byte-by-byte Description of file: spectrum.dat
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Bytes Format Units Label Explanations
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1- 16 F16.9 MHz Freq Frequency
19- 25 F7.4 K Int Intensity
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Acknowledgements:
Pierre Marchand, pierre.marchand.astr(at)gmail.com
(End) Patricia Vannier [CDS] 15-May-2024