Early Planet Formation in Embedded Disks (eDisk) XV: Influence of Magnetic Field Morphology in Dense Cores on Sizes of Protostellar Disks

By Keith Cowing
Status Report
May 16, 2024
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Early Planet Formation in Embedded Disks (eDisk) XV: Influence of Magnetic Field Morphology in Dense Cores on Sizes of Protostellar Disks
Early Planet Formation In An Embedded Disk — NASA

The magnetic field of a molecular cloud core may play a role in the formation of circumstellar disks in the core. We present magnetic field morphologies in protostellar cores of 16 targets in the Atacama Large Millimeter/submillimeter Array large program “Early Planet Formation in Embedded Disks (eDisk)”, which resolved their disks with 7 au resolutions.

The 0.1-pc scale magnetic field morphologies were inferred from the James Clerk Maxwell Telescope (JCMT) POL-2 observations. The mean orientations and angular dispersions of the magnetic fields in the dense cores are measured and compared with the radii of the 1.3 mm continuum disks and the dynamically determined protostellar masses from the eDisk program. We observe a significant correlation between the disk radii and the stellar masses.

We do not find any statistically significant dependence of the disk radii on the projected misalignment angles between the rotational axes of the disks and the magnetic fields in the dense cores, nor on the angular dispersions of the magnetic fields within these cores. However, when considering the projection effect, we cannot rule out a positive correlation between disk radii and misalignment angles in three-dimensional space.

Our results suggest that the morphologies of magnetic fields in dense cores do not play a dominant role in the disk formation process. Instead, the sizes of protostellar disks may be more strongly affected by the amount of mass that has been accreted onto star+disk systems, and possibly other parameters, for example, magnetic field strength, core rotation, and magnetic diffusivity.

JCMT 850 µm Stokes I intensity maps of the eDisk targets. Crosses denote the protostellar positions measured with the eDisk program (Ohashi et al. 2023). Orange segments present the magnetic field orientations inferred from the JCMT POL-2 data with polarization detections above 2σ, and the uncertainties in their orientations are all smaller than 14◦ . Blue filled circles show the angular resolution of 14. ′′6. Red and blue arrows denote the directions of the known blueshifted and redshifted outflows. Contour levels start from 2.5% of the peak intensity (Table 2) and increase in steps of a factor of 2. For L1489 IRS, GSS30 IRS3, and R CrA IRS7B and IRS5N, the cyan contours outline the core areas identified with dendrogram. The maps are arranged from top to bottom and from left to right in descending order of the disk sizes. — astro-ph.SR

Hsi-Wei Yen, Jonathan P. Williams, Jinshi Sai (Insa Choi), Patrick M. Koch, Ilseung Han, Jes K. Jørgensen, Woojin Kwon, Chang Won Lee, Zhi-Yun Li, Leslie W. Looney, Mayank Narang, Nagayoshi Ohashi, Shigehisa Takakuwa, John J. Tobin, Itziar de Gregorio-Monsalvo, Shih-Ping Lai, Jeong-Eun Lee, Kengo Tomida

Comments: 14 pages, 4 figures, accepted by ApJ
Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
Cite as: arXiv:2405.09063 [astro-ph.SR] (or arXiv:2405.09063v1 [astro-ph.SR] for this version)
Submission history
From: Hsi-Wei Yen
[v1] Wed, 15 May 2024 03:27:11 UTC (595 KB)


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