Abstract We observed the high-mass protostellar core G335.579–0.272 ALMA1 at ∼200 au (0.″05) resolution with the Atacama Large Millimeter/submillimeter Array (ALMA) at 226 GHz (with a mass sensitivity of 5 σ = 0.2 M ⊙ at 10 K). We discovered that at least a binary system is forming inside this region, with an additional nearby bow-like structure (≲1000 au) that could add an additional member to the stellar system. These three sources are located at the center of the gravitational potential well of the ALMA1 region and the larger MM1 cluster. The emission from CH 3 OH (and many other tracers) is extended (>1000 au), revealing a common envelope toward the binary system. We use CH 2 CHCN line emission to estimate an inclination angle of the rotation axis of 26° with respect to the line of sight based on geometric assumptions and derive a kinematic mass of the primary source (protostar+disk) of 3.0 M ⊙ within a radius of 230 au. Using SiO emission, we find that the primary source drives the large-scale outflow revealed by previous observations. Precession of the binary system likely produces a change in orientation between the outflow at small scales observed here and large scales observed in previous works. The bow structure may have originated from the entrainment of matter into the envelope due to the widening or precession of the outflow, or, alternatively, an accretion streamer dominated by the gravity of the central sources. An additional third source, forming due to instabilities in the streamer, cannot be ruled out as a temperature gradient is needed to produce the observed absorption spectra.
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PRODIGE – envelope to disk with NOEMA: II. Small-scale temperature structure and streamer feeding the SVS13A protobinary based on CH 3 CN and DCN
Aims. We present high-sensitivity and high spectral-resolution NOEMA observations of the Class 0/I binary system SVS13A, composed of the low-mass protostars VLA4A and VLA4B, with a separation of ~90 au. VLA4A is undergoing an accretion burst that is enriching the chemistry of the surrounding gas, which provides an excellent opportunity to probe the chemical and physical conditions as well as the accretion process. Methods. We observe the (12 K –11 K ) lines of CH 3 CN and CH 3 13 CN, the DCN (3–2) line, and the C 18 O (2–1) line toward SVS13A using NOEMA. Results. We find complex line profiles at disk scales that cannot be explained by a single component or pure Keplerian motion. By adopting two velocity components to model the complex line profiles, we find that the temperatures and densities are significantly different among these two components. This suggests that the physical conditions of the emitting gas traced via CH 3 CN can change dramatically within the circumbinary disk. In addition, combining our observations of DCN (3–2) with previous ALMA observations at high angular resolution, we find that the binary system (or VLA4A) might be fed by an infalling streamer from envelope scales (~700 au). If this is the case, this streamer contributes to the accretion of material onto the system at a rate of at least 1.4 × 10 −6 M ⊙ yr −1 . Conclusions. We conclude that the CH 3 CN emission in SVS13A traces hot gas from a complex structure. This complexity might be affected by a streamer that is possibly infalling and funneling material into the central region.
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- Award ID(s):
- 2102405
- NSF-PAR ID:
- 10437249
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Date Published:
- Journal Name:
- Astronomy & Astrophysics
- Volume:
- 669
- ISSN:
- 0004-6361
- Page Range / eLocation ID:
- A137
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1051/0004-6361/202244183
