Discovery of a 500 au Protobinary in the Massive Prestellar Core G11.92–0.61 MM2

Cyganowski, C. J.; Ilee, J. D.; Brogan, C. L.; Hunter, T. R.; Zhang, S.; Harries, Tim J.; Haworth, Thomas J.

doi:10.3847/2041-8213/ac69ca

Cited by 7 publications

(1 citation statement)

References 51 publications

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“…Several observations have revealed massive binary formation at the protostellar phase (e.g., Beltrán et al 2016;Tanaka et al 2020). Most recently, Cyganowski et al (2022) observed a (proto)binary in a massive core that was previously thought to be prestellar, making it one of the earliest-stage forming binaries that has the potential to become massive. Such observations put stringent constraints on massive binary formation theories (e.g., Krumholz et al 2009;Oliva & Kuiper 2020;Mignon-Risse et al 2021).…”

Section: Introductionmentioning

confidence: 99%

Binary Formation in a 100 μm Dark Massive Core

Kong

Arce

Tobin

et al. 2023

ApJ

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We report high-resolution ALMA observations toward a massive protostellar core C1-Sa (∼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 ∼1400 au along the elongation of C1-Sa, consistent with a Jeans length scale of ∼1100 au. Radiative transfer modeling using RADEX indicates that the protostellar kernel C1-Sa1 has a temperature of ∼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-H2D+ and N2D+ 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 subkernels with similar masses, which requires further confirmation with higher sensitivity.

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Section: Introductionmentioning

confidence: 99%

Binary Formation in a 100 μm Dark Massive Core

Kong

Arce

Tobin

et al. 2023

ApJ

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Observations of high-order multiplicity in a high-mass stellar protocluster

Li,

Sanhueza,

Beuther

et al. 2024

Nat Astron

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The dominant mechanism forming multiple stellar systems in the high-mass regime (M* ≳ 8 M⊙) remained unknown because direct imaging of multiple protostellar systems at early phases of high-mass star formation is very challenging. High-mass stars are expected to form in clustered environments containing binaries and higher-order multiplicity systems. So far only a few high-mass protobinary systems, and no definitive higher-order multiples, have been detected. Here we report the discovery of one quintuple, one quadruple, one triple and four binary protostellar systems simultaneously forming in a single high-mass protocluster, G333.23–0.06, using Atacama Large Millimeter/submillimeter Array high-resolution observations. We present a new example of a group of gravitationally bound binary and higher-order multiples during their early formation phases in a protocluster. This provides the clearest direct measurement of the initial configuration of primordial high-order multiple systems, with implications for the in situ multiplicity and its origin. We find that the binary and higher-order multiple systems, and their parent cores, show no obvious sign of disk-like kinematic structure. We conclude that the observed fragmentation into binary and higher-order multiple systems can be explained by core fragmentation, indicating its crucial role in establishing the multiplicity during high-mass star cluster formation.

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ALMA observations of the Extended Green Object G19.01–0.03 – ii. A massive protostar with typical chemical abundances surrounded by four low-mass pre-stellar core candidates

Williams,

Cyganowski,

Brogan

et al. 2023

Monthly Notices of the Royal Astronomical Society

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We present a study of the physical and chemical properties of the Extended Green Object (EGO) G19.01−0.03 using sub-arcsecond angular resolution Atacama Large Millimetre/submillimetre Array (ALMA) 1.05 mm and Karl G. Jansky Very Large Array (VLA) 1.21 cm data. G19.01−0.03 MM1, the millimetre source associated with the central massive young stellar object (MYSO), appeared isolated and potentially chemically young in previous Submillimetre Array observations. In our ∼0.4 arcsec-resolution ALMA data, MM1 has four low-mass millimetre companions within 0.12 pc, all lacking maser or outflow emission, indicating they may be pre-stellar cores. With a rich ALMA spectrum full of complex organic molecules, MM1 does not appear chemically young, but has molecular abundances typical of high-mass hot cores in the literature. At the 1.05 mm continuum peak of MM1, N(CH3OH) = (2.22 ± 0.01) × 1018 cm−2 and $T_{\mathrm{ex}} = 162.7\substack{+0.3 \\ -0.5}$ K based on pixel-by-pixel Bayesian analysis of LTE synthetic methanol spectra across MM1. Intriguingly, the peak CH3OH Tex = 165.5 ± 0.6 K is offset from MM1’s millimetre continuum peak by 0.22 arcsec ∼ 880 au, and a region of elevated CH3OH Tex coincides with free–free VLA 5.01 cm continuum, adding to the tentative evidence for a possible unresolved high-mass binary in MM1. In our VLA 1.21 cm data, we report the first NH3(3,3) maser detections towards G19.01−0.03, along with candidate 25 GHz CH3OH 5(2, 3) − 5(1, 4) maser emission; both are spatially and kinematically coincident with 44 GHz Class I CH3OH masers in the MM1 outflow. We also report the ALMA detection of candidate 278.3 GHz Class I CH3OH maser emission towards this outflow, strengthening the connection of these three maser types to MYSO outflows.

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Discovery of a 500 au Protobinary in the Massive Prestellar Core G11.92–0.61 MM2

Cited by 7 publications

References 51 publications

Binary Formation in a 100 μm Dark Massive Core

Binary Formation in a 100 μm Dark Massive Core

Observations of high-order multiplicity in a high-mass stellar protocluster

ALMA observations of the Extended Green Object G19.01–0.03 – ii. A massive protostar with typical chemical abundances surrounded by four low-mass pre-stellar core candidates

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