Physical and chemical characteristics of l1689-smm16, an oscillating prestellar core in Ophiuchus

Par Conseil national de recherches du Canada

DOI	Trouver le DOI : https://doi.org/10.1088/0004-637X/790/2/129
Auteur	Rechercher : Chitsazzadeh, S.¹; Rechercher : Di Francesco, J.¹; Rechercher : Schnee, S.; Rechercher : Friesen, R. K.; Rechercher : Shimajiri, Y.; Rechercher : Langston, G. I.; Rechercher : Sadavoy, S. I.¹; Rechercher : Bourke, T. L.; Rechercher : Keto, E. R.; Rechercher : Pineda, J. E.; Rechercher : Takakuwa, S.; Rechercher : Tatematsu, K.
Affiliation	Conseil national de recherches du Canada. Infrastructure scientifique nationale
Format	Texte, Article
Sujet	ISM: kinematics and dynamics; ISM: molecules; ISM: structure; radio lines: ISM; stars: formation
Résumé	We present single-dish observations of the L1689-SMM16 core in the Ophiuchus molecular cloud in NH3 (1, 1) and (2, 2) emission using the Green Bank Telescope, in N2H+ (1-0) emission using the Nobeyama Radio Observatory, and in NH2D (), HCN (1-0), HNC (1-0), H 13CO+ (1-0), and HCO+ (1-0) emission using the Mopra telescope. The morphologies of the integrated NH3 (1, 1) and N2H+ (1-0) emission well match that of 250 μm continuum emission. Line widths of NH3 (1, 1) and N2H+ (1-0) show the presence of transonic turbulence across the core. Jeans and virial analyses made using updated measurements of core mass and size confirm that L1689-SMM16 is prestellar, i.e., gravitationally bound. It also has accumulated more mass compared to its corresponding Jeans mass in the absence of magnetic fields and therefore is a "super-Jeans" core. The high levels of X(NH 3)/X(N2H+) and deuterium fractionation reinforce the idea that the core has not yet formed a protostar. Comparing the physical parameters of the core with those of a Bonnor-Ebert sphere reveals the advanced evolutionary stage of L1689-SMM16 and shows that it might be unstable to collapse. We do not detect any evidence of infall motions toward the core. Instead, red asymmetry in the line profiles of HCN (1-0) and HNC (1-0) indicates the expansion of the outer layers of the core at a speed of 0.2 km s -1 to 0.3 km s-1. For a gravitationally bound core, expansion in the outer layers might indicate that the core is experiencing oscillations.
Date de publication	2014-07-15
Maison d’édition	American Astronomical Society IOP Publishing
Dans	The Astrophysical Journal 790, nº 2, 129 : 1–21.
Langue	anglais
Publications évaluées par des pairs	Oui
Numéro NPARC	21272720
Exporter la notice	Exporter en format RIS
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Identificateur de l’enregistrement	112c4e5c-4693-42f1-86b1-f6f17c34aa26
Enregistrement créé	2014-12-03
Enregistrement modifié	2020-04-22

Date de modification :: 2024-06-29