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Kinematics and stability of high-mass protostellar disk candidates at sub-arcsecond resolution -- Insights from the IRAM NOEMA large program CORE

Ahmadi, A, Beuther, H, Bosco, F, Gieser, C, Suri, S, Mottram, JC, Kuiper, R, Henning, T, Sánchez-Monge, Á, Linz, H, Pudritz, RE, Semenov, D, Winters, JM, Möller, T, Beltrán, MT, Csengeri, T, Galván-Madrid, R, Johnston, KG, Keto, E, Klaassen, PD , Leurini, S, Longmore, SN, Lumsden, SL, Maud, LT, Moscadelli, L, Palau, A, Peters, T, Ragan, SE, Urquhart, JS, Zhang, Q and Zinnecker, H Kinematics and stability of high-mass protostellar disk candidates at sub-arcsecond resolution -- Insights from the IRAM NOEMA large program CORE. Astronomy and Astrophysics. ISSN 0004-6361 (Accepted)

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The fragmentation mode of high-mass molecular clumps and the accretion processes that form the most massive stars (M≳8M⊙) are still not well understood. To this end, we have undertaken a large observational program (CORE) making use of interferometric observations from the Northern Extended Millimetre Array (NOEMA) for a sample of 20 luminous (L>104L⊙) protostellar objects in the 1.37 mm wavelength regime in both continuum and line emission, reaching ∼0.4" resolution (800 au at 2 kpc). Using the dense gas tracer CH3CN, we find velocity gradients across 13 cores perpendicular to the directions of bipolar molecular outflows, making them excellent disk candidates. Specific angular momentum (j) radial profiles are on average ∼10−3 km /s pc and follow j∝r1.7, consistent with a poorly resolved rotating and infalling envelope/disk model. Fitting the velocity profiles with a Keplerian model, we find protostellar masses in the range of ∼10−25 M⊙. Modelling the level population of CH3CN lines, we present temperature maps and find median gas temperatures in the range 70−210 K. We create Toomre Q maps to study the stability of the disks and find almost all (11 of 13) disk candidates to be prone to fragmentation due to gravitational instabilities at the scales probed by our observations. In particular, disks with masses greater than ∼10−20% of the mass of their host (proto)stars are Toomre unstable, and more luminous protostellar objects tend to have disks that are more massive and hence more prone to fragmentation. Our finings show that most disks around high-mass protostars are prone to disk fragmentation early in their formation due to their high disk to stellar mass ratio. This impacts the accretion evolution of high-mass protostars which will have significant implications for the formation of the most massive stars.

Item Type: Article
Uncontrolled Keywords: astro-ph.GA; astro-ph.GA; astro-ph.SR
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Astrophysics Research Institute
Publisher: EDP Sciences
Related URLs:
SWORD Depositor: A Symplectic
Date Deposited: 11 May 2023 11:50
Last Modified: 11 May 2023 12:00
URI: https://researchonline.ljmu.ac.uk/id/eprint/19468

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