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Author (up) Nogueira, P.H.; Zurlo, A.; Perez, S.; Gonzalez-Ruilova, C,; Cieza, L.A.; Hales, A.; Bhowmik, T.; Ruiz-Rodriguez, D.A.; Principe, D.A.; Herczeg, G.J.; Williams, J.P.; Cuadra, J.; Montesinos, M.; Cuello, N.; Chavan, P.; Casassus, S.; Zhu, Z.H.; Goicovic, F.G.
Title Resolving the binary components of the outbursting protostar HBC 494 with ALMA Type
Year 2023 Publication Monthly Notices Of The Royal Astronomical Society Abbreviated Journal Mon. Not. Roy. Astron. Soc.
Volume 523 Issue 4 Pages 4970-4991
Keywords accretion; accretion discs; protoplanetary discs; stars: protostarsI; SM: jets and outflows; radio continuum: planetary systems; radio lines: planetary systems
Abstract Episodic accretion is a low-mass pre-main sequence phenomenon characterized by sudden outbursts of enhanced accretion. These objects are classified into two: protostars with elevated levels of accretion that lasts for decades or more, called FUors, and protostars with shorter and repetitive bursts, called EXors. HBC 494 is a FUor object embedded in the Orion Molecular Cloud. Earlier Atacama Large (sub-)Millimeter Array (ALMA) continuum observations showed an asymmetry in the disc at 0.“2 resolution. Here, we present follow-up observations at similar to 0.”03, resolving the system into two components: HBC 494 N (primary) and HBC 494 S (secondary). No circumbinary disc was detected. Both discs are resolved with a projected separation of similar to 0."18 (75 au). Their projected dimensions are 84 +/- 1.8 x66.9 +/- 1.5 mas for HBC 494 N and 64.6 +/- 2.5 x46.0 +/- 1.9 mas for HBC 494 S. The discs are almost aligned and with similar inclinations. The observations show that the primary is similar to 5 times brighter/more massive and similar to 2 times bigger than the secondary. We notice that the northern component has a similar mass to the FUors, while the southern has to EXors. The HBC 494 discs show individual sizes that are smaller than single eruptive YSOs. In this work, we also report (CO)-C-12, (CO)-C-13, and (CO)-O-18 molecular line observations. At large scale, the (CO)-C-12 emission shows bipolar outflows, while the (CO)-C-13 and (CO)-O-18 maps show a rotating and infalling envelope around the system. At a smaller scale, the (CO)-C-12 and (CO)-C-13 moment zero maps show cavities within the continuum discs' area, which may indicate continuum over-subtraction or slow-moving jets and chemical destruction along the line of sight.
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ISSN 0035-8711 ISBN Medium
Area Expedition Conference
Notes WOS:001023895800007 Approved
Call Number UAI @ alexi.delcanto @ Serial 1869
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