Binary Formation in a 100 $μ$m-dark Massive Core

Shuo Kong; Héctor G. Arce; John J. Tobin; Yichen Zhang; María José Maureira; Kaitlin M. Kratter; Thushara G. S. Pillai

doi:10.3847/1538-4357/acd252

paper

Binary Formation in a 100 $μ$ m-dark Massive Core

arXiv:2305.02286 · doi:10.3847/1538-4357/acd252

Abstract

We report high-resolution ALMA observations toward a massive protostellar core C1-Sa ( $\sim$ 30 M $_{⊙}$ ) in the Dragon Infrared Dark Cloud. At the resolution of 140 AU, the core fragments into two kernels (C1-Sa1 and C1-Sa2) with a projected separation of $\sim$ 1400 AU along the elongation of C1-Sa, consistent with a Jeans length scale of $\sim$ 1100 AU. Radiative transfer modeling using RADEX indicates that the protostellar kernel C1-Sa1 has a temperature of $\sim$ 75 K and a mass of 0.55 M $_{⊙}$ . C1-Sa1 also likely drives two bipolar outflows, one being parallel to the plane-of-the-sky. C1-Sa2 is not detected in line emission and does not show any outflow activity but exhibits ortho-H $_{2}$ D $^{+}$ and N $_{2}$ D $^{+}$ emission in its vicinity, thus it is likely still starless. Assuming a 20 K temperature, C1-Sa2 has a mass of 1.6 M $_{⊙}$ . At a higher resolution of 96 AU, C1-Sa1 begins to show an irregular shape at the periphery, but no clear sign of multiple objects or disks. We suspect that C1-Sa1 hosts a tight binary with inclined disks and outflows. Currently, one member of the binary is actively accreting while the accretion in the other is significantly reduced. C1-Sa2 shows hints of fragmentation into two sub-kernels with similar masses, which requires further confirmation with higher sensitivity.

arXiv comment7 figures, 2 tables, accepted by ApJ

Binary Formation in a 100 μm-dark Massive Core

Abstract

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Binary Formation in a 100 $μ$ m-dark Massive Core