Exoplanetology: Exoplanets & Exomoons

Early Planet Formation in Embedded Disks (eDisk). XI. A High-resolution View Toward the BHR 71 Class 0 Protostellar Wide Binary

By Keith Cowing
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astro-ph.EP
July 26, 2024
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Early Planet Formation in Embedded Disks (eDisk). XI. A High-resolution View Toward the BHR 71 Class 0 Protostellar Wide Binary
Continuum emission at 1.3 mm with robust parameter r = 0.5 for IRS1 (top row) and IRS2 (bottom row). The right panels are zoomed-in views of the left panels. The white contours in the right panels represent increasing selected values of σ [7σ, 14σ, 70σ, 140σ, 700σ] and [15σ, 40σ, 80σ] for IRS1 and IRS2, respectively. The 4σ contour level for IRS2 is also shown in panel c. The white ellipse represents the beam size. The red lines follow the position angle of the semi-major axis as derived from the best-fit model (in IRS2, the direction of the red line does not follow the apparent semi-major axis because the image is marginally resolved). Note that the color scales are not identical but depend on the peak intensity in each panel. –astro-ph.EP

We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of the binary Class 0 protostellar system BHR 71 IRS1 and IRS2 as part of the Early Planet Formation in Embedded Disks (eDisk) ALMA Large Program.

We describe the 12CO (J=2–1), 13CO (J=2–1), C18O (J=2–1), H2CO (J=32,1–22,0), and SiO (J=5–4) molecular lines along with the 1.3 mm continuum at high spatial resolution (∼0.08″ or ∼5 au). Dust continuum emission is detected toward BHR 71 IRS1 and IRS2, with a central compact component and extended continuum emission. The compact components are smooth and show no sign of substructures such as spirals, rings or gaps.

However, there is a brightness asymmetry along the minor axis of the presumed disk in IRS1, possibly indicative of an inclined geometrically and optically thick disk-like component. Using a position-velocity diagram analysis of the C18O line, clear Keplerian motions were not detected toward either source. If Keplerian rotationally-supported disks are present, they are likely deeply embedded in their envelope. However, we can set upper limits of the central protostellar mass of 0.46 M⊙ and 0.26 M⊙ for BHR 71 IRS1 and BHR 71 IRS2, respectively. Outflows traced by 12CO and SiO are detected in both sources.

The outflows can be divided into two components, a wide-angle outflow and a jet. In IRS1, the jet exhibits a double helical structure, reflecting the removal of angular momentum from the system. In IRS2, the jet is very collimated and shows a chain of knots, suggesting episodic accretion events.

Sacha Gavino, Jes K. Jørgensen, Rajeeb Sharma, Yao-Lun Yang, Zhi-Yun Li, John J. Tobin, Nagayoshi Ohashi, Shigehisa Takakuwa, Adele Plunkett, Woojin Kwon, Itziar de Gregorio-Monsalvo, Zhe-Yu Daniel Lin, Alejandro Santamaría-Miranda, Yusuke Aso, Jinshi Sai (Insa Choi), Yuri Aikawa, Kengo Tomida, Patrick M. Koch, Jeong-Eun Lee, Chang Won Lee, Shih-Ping Lai, Leslie W. Looney, Suchitra Narayanan, Nguyen Thi Phuong, Travis J. Thieme, Merel L. R. van ‘t Hoff, Jonathan P. Willians, Hsi-Wei Yen

Comments: 38 pages, 29 figures, accepted in ApJ
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2407.17249 [astro-ph.EP] (or arXiv:2407.17249v1 [astro-ph.EP] for this version)
Related DOI:
https://doi.org/10.3847/1538-4357/ad655e
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Submission history
From: Sacha Gavino
[v1] Wed, 24 Jul 2024 13:10:24 UTC (40,116 KB)
https://arxiv.org/abs/2407.17249

Astrobiology,

Keith Cowing

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻

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