文章基本信息

标题：Mirror, mirror on the outflow cavity wall
其他标题：Near-infrared CO overtone disc emission of the high-mass YSO IRAS 11101-5829★
本地全文：下载
作者：R. Fedriani ; A. Caratti o Garatti ; M. Koutoulaki 等
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2020
卷号：633
页码：1-11
DOI：10.1051/0004-6361/201936748
语种：English
出版社：EDP Sciences
摘要：Aims.The inner regions of high-mass protostars are often invisible in the near-infrared, obscured by thick envelopes and discs. We aim to investigate the inner gaseous disc of IRAS 11101-5829 through scattered light from the outflow cavity walls.Methods.We observed the immediate environment of the high-mass young stellar object IRAS 11101-5829 and the closest knots of its jet, HH135-136, with the integral field unit VLT/SINFONI. We also retrieved archival data from the high-resolution long-slit spectrograph VLT/X-shooter. We analysed imaging and spectroscopic observations to discern the nature of the near-infrared CO emission.Results.We detect the first three bandheads of theυ= 2−0 CO vibrational emission for the first time in this object. It is coincident with continuum and Brγemission and extends up to ~10 000 au to the north-east and ~10 000 au to the south-west. The line profiles have been modelled as a Keplerian rotating disc assuming a single ring in local thermodynamic equilibrium. The model output gives a temperature of ~3000 K, a CO column density of ~1 × 1022cm−2, and a projected Keplerian velocityvKsinidisc~ 25 km s−1, which is consistent with previous modelling in other high-mass protostars. In particular, the low value ofvKsinidiscsuggests that the disc is observed almost face-on, whereas the well-constrained geometry of the jet imposes that the disc must be close to edge-on. This apparent discrepancy is interpreted as the CO seen reflected in the mirror of the outflow cavity wall.Conclusions.From both jet geometry and disc modelling, we conclude that all the CO emission is seen through reflection by the cavity walls and not directly. This result implies that in the case of highly embedded objects, as for many high-mass protostars, line profile modelling alone might be deceptive and the observed emission could affect the derived physical and geometrical properties; in particular the inclination of the system can be incorrectly interpreted.
关键词：Key wordsenaccretion, accretion disksISM: jets and outflowsstars: protostarsstars: massivestars: individual: IRAS 11101-5829ISM: individual objects: HH 135-HH 136