| 研究実績の概要 |
The whole project is to search, identify, and study the rotationally supported disks around massive protostars. In 2019, We have published a paper on the massive protostellar source G339 in the Astrophysical Journal, which we have reported direct observation of the transition from an infalling envelope to a rotationally supported disk accompanied by change of chemical signatures. This is the first time that such transition has been identified with chemical signatures in massive star formation, which provides important guide for our future search for such sources. We also published a paper about another massive protostar G45 in the Astrophysical Journal Letters, which we have identify the disk via observation of recombination lines of ionized gas, which provide another approach to search disks around massive protostars. In another massive protostellar source IRAS16547, we have identified chemical patterns similar to G339, with certain molecules exclusively trace the rotationally supported disks, which may be used as reliable disk diagnostic tools in the future.
We have applied following-up observations of the ALMA telescope to perform more detailed observations for G339 and G45. Both projects are approved and assigned with top rank priority. The observations are expected to be done later this year and data will be delivered to us soon after the observations are complete.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
The original plans for 2019 are 1) expand our search for rotationally supported disk with our currently obtained data; 2) apply for detailed study on the sources we have identified disks; 3) detailed study on the massive protobinary systems. For goal 1), now we have identified disks using different tracers in three sources in total. For goal 2), now we have successfully applied new observations as planed. For goal 3), we have obtained part of the data we have required and possible new observations later this year. The data are in analysis. In general, the project is progressing smoothly.
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| 今後の研究の推進方策 |
Analysis of the newly obtained data will be the focus of this research in this year. This includes 1) identify all the molecule lines and identify which are tracing the disks and which are tracing the envelope to provide a set of lines can be used in future studies to efficiently search for disks in massive star formation. 2) study the kinematics based on the observed line data, to identify the rotation profile of the disks and envelopes, the angular momentum transition from the envelope to the disk and to the binary system, the interaction of the circumstellar disks and circumbinary disk in the protobinary systems. We also plan to further expand our search on massive protostellar disks by observing a larger sample of sources.
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