SMA observations towards the compact, short-lived bipolar water maser outflow in the LkHα234 region
| Autor: | M. A. Trinidad, Nimesh A. Patel, Jorge Cantó, Carlos Carrasco-González, José-Luis Gómez, Guillem Anglada, Luis F. Rodríguez, Robert Estalella, Salvador Curiel, J. M. Girart, José M. Torrelles |
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| Přispěvatelé: | Universitat de Barcelona |
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
media_common.quotation_subject
Astrophysics Rotation 01 natural sciences Submillimeter Array law.invention Accretion rate law Bipolar outflow 0103 physical sciences Maser Molècules 010303 astronomy & astrophysics media_common Physics 010308 nuclear & particles physics Star formation Astronomy Astronomy and Astrophysics Molecules Formació d'estels Astrophysics - Astrophysics of Galaxies Radial velocity Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science Sky Outflow |
| Zdroj: | Recercat. Dipósit de la Recerca de Catalunya instname Dipòsit Digital de la UB Universidad de Barcelona |
| Popis: | We present Submillimeter Array (SMA) 1.35 mm subarcsecond angular resolution observations toward the LkH{\alpha} 234 intermediate-mass star-forming region. The dust emission arises from a filamentary structure of $\sim$5 arcsec ($\sim$4500 au) enclosing VLA 1-3 and MM 1, perpendicular to the different outflows detected in the region. The most evolved objects are located at the southeastern edge of the dust filamentary structure and the youngest ones at the northeastern edge. The circumstellar structures around VLA 1, VLA 3, and MM 1 have radii between $\sim$200 and $\sim$375 au and masses in the $\sim$0.08-0.3 M$_{\odot}$ range. The 1.35 mm emission of VLA 2 arises from an unresolved (r$< 135$ au) circumstellar disk with a mass of $\sim$0.02 M$_{\odot}$. This source is powering a compact ($\sim$4000 au), low radial velocity ($\sim$7 km s$^{-1}$) SiO bipolar outflow, close to the plane of the sky. We conclude that this outflow is the "large-scale" counterpart of the short-lived, episodic, bipolar outflow observed through H$_2$O masers at much smaller scales ($\sim $180 au), and that has been created by the accumulation of the ejection of several episodic collimated events of material. The circumstellar gas around VLA 2 and VLA 3 is hot ($\sim$130 K) and exhibits velocity gradients that could trace rotation. There is a bridge of warm and dense molecular gas connecting VLA 2 and VLA 3. We discuss the possibility that this bridge could trace a stream of gas between VLA 3 and VLA 2, increasing the accretion rate onto VLA 2 to explain why this source has an important outflow activity. Comment: 11 pages, 9 figures, accepted for publication in MNRAS |
| Databáze: | OpenAIRE |
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