Volume 612, April 2018
|Number of page(s)||11|
|Section||Interstellar and circumstellar matter|
|Published online||27 April 2018|
Binary energy source of the HH 250 outflow and its circumstellar environment★
European Southern Observatory,
Alonso de Córdova 3107,
2 Institute for Astronomy, University of Hawaii at Manoa, 640 N. Aohoku Place, Hilo HI 96720, USA
3 European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, Germany
Accepted: 28 December 2017
Aims. Herbig-Haro flows are signposts of recent major accretion and outflow episodes. We aim to determine the nature and properties of the little-known outflow source HH 250-IRS, which is embedded in the Aquila clouds.
Methods. We have obtained adaptive optics-assisted L-band images with the NACO instrument on the Very Large Telescope (VLT), together with N- and Q-band imaging with VISIR also on the VLT. Using the SINFONI instrument on the VLT we carried out H- and K-band integral field spectroscopy of HH 250-IRS, complemented with spectra obtained with the SpeX instrument at the InfraRed Telescope Facility (IRTF) in the JHKL bands. Finally, the SubMillimeter Array (SMA) interferometer was used to study the circumstellar environment of HH 250-IRS at 225 and 351 GHz with CO (2–1) and CO (3–2) maps and 0.9 mm and 1.3 mm continuum images.
Results. The HH 250-IRS source is resolved into a binary with 0.′′53 separation, corresponding to 120 AU at the adopted distance of 225 pc. The individual components show heavily veiled spectra with weak CO absorption indicative of late-type stars. Both are Class I sources, but their spectral energy distributions between 1.5 μm and 19 μm differ markedly and suggest the existence of a large cavity around one of the components. The millimeter interferometric observations indicate that the gas mainly traces a circumbinary envelope or disk, while the dust emission is dominated by one of the circumstellar envelopes.
Conclusions. HH 250-IRS is a new addition to the handful of multiple systems where the individual stellar components, the circumstellar disks and a circumbinary disk can be studied in detail, and a rare case among those systems in which a Herbig-Haro flow is present.
Key words: circumstellar matter / stars: winds, outflows / stars: individual: IRAS 19190+1048 / stars: pre-main sequence / ISM: jets and outflows / binaries: general
Based on observations obtained with the VLT (Cerro Paranal, Chile) in programs 089.C-0196(A), 095.C-0488(A), and 095.C-0488(B), as well as with IRTF (Mauna Kea, Hawaii), SMA (Mauna Kea, Hawaii), and the Nordic Optical Telescope (La Palma, Canary Islands, Spain).
© ESO 2018
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