Laboratory measurements and astronomical search for cyanomethanimine

Status Report From: e-Print archive
Posted: Thursday, December 21, 2017

Mattia Melosso, Alessio Melli, Cristina Puzzarini, Claudio Codella, Lorenzo Spada, Luca Dore, Claudio Degli Esposti, Bertrand Lefloch, Rafael Bachiller, Cecilia Ceccarelli, José Cernicharo, Vincenzo Barone
(Submitted on 5 Dec 2017)

C-cyanomethanimine (HNCHCN), existing in the two Z and E isomeric forms, is a key prebiotic molecule, but, so far, only the E isomer has been detected toward the massive star-forming region. Sagittarius B2(N) using transitions in the radio wavelength domain. With the aim of detecting HNCHCN in Sun-like-star forming regions, the laboratory investigation of its rotational spectrum has been extended to the millimeter-/submillimeter-wave (mm-/submm-) spectral window in which several unbiased spectral surveys have been already carried out. High-resolution laboratory measurements of the rotational spectrum of C-cyanomethanimine were carried out in the 100-420 GHz range using a frequency-modulation absorption spectrometer. We then searched for the C-cyanomethanimine spectral features in the mm-wave range using the high-sensitivity and unbiased spectral surveys obtained with the IRAM 30-m antenna in the ASAI context, the earliest stages of star formation from starless to evolved Class I objects being sampled. For both the Z and E isomers, the spectroscopic work has led to an improved and extended knowledge of the spectroscopic parameters, thus providing accurate predictions of the rotational signatures up to ∼700 GHz. So far, no C-cyanomethanimine emission has been detected toward the ASAI targets, and upper limits of the column density of ∼ 1011--1012 cm−2 could only be derived. Consequently, the C-cyanomethanimine abundances have to be less than a few 10−10 for starless and hot-corinos. A less stringent constraint, ≤ 10−9, is obtained for shocks sites. The combination of the upper limits of the abundances of C-cyanomethanimine together with accurate laboratory frequencies up to ∼ 700 GHz poses the basis for future higher sensitivity searches around Sun-like-star forming regions.

Comments:    9 pages, 4 figures, 2 tables. A&A accepted
Subjects:    Astrophysics of Galaxies (astro-ph.GA)
DOI:    10.1051/0004-6361/201731972
Cite as:    arXiv:1712.01543 [astro-ph.GA] (or arXiv:1712.01543v1 [astro-ph.GA] for this version)
Submission history
From: Mattia Melosso
[v1] Tue, 5 Dec 2017 09:46:49 GMT (1855kb)

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