title: Circumstellar disks of the most vigorously accreting young stars.
abstract: Stars may not accumulate their mass steadily, as was previously thought, but in a series of violent events manifesting themselves as sharp stellar brightening. These events can be caused by fragmentation due to gravitational instabilities in massive gaseous disks surrounding young stars, followed by migration of dense gaseous clumps onto the star. Our high-resolution near-infrared imaging has verified the presence of the key associated features, large-scale arms and arcs surrounding four young stellar objects undergoing luminous outbursts. Our hydrodynamics simulations and radiative transfer models show that these observed structures can indeed be explained by strong gravitational instabilities occurring at the beginning of the disk formation phase. The effect of those tempestuous episodes of disk evolution on star and planet formation remains to be understood.
authors.affiliation: Academia Sinica Institute of Astronomy and Astrophysics, Taipei 10617, Taiwan.
authors.forename: Hauyu Baobab
authors.initials: HB
authors.lastname: Liu
authors.affiliation: Academia Sinica Institute of Astronomy and Astrophysics, Taipei 10617, Taiwan.
authors.forename: Michihiro
authors.identifier: 0000-0001-9248-7546
authors.initials: M
authors.lastname: Takami
authors.affiliation: National Astronomical Observatory of Japan, Tokyo 181-8588, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kudo
authors.affiliation: National Astronomical Observatory of Japan, Tokyo 181-8588, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Hashimoto
authors.affiliation: Academia Sinica Institute of Astronomy and Astrophysics, Taipei 10617, Taiwan.; Astronomy Department, University of California Berkeley, Berkeley, CA 94720, USA.
authors.forename: Ruobing
authors.initials: R
authors.lastname: Dong
authors.affiliation: Department of Astrophysics, University of Vienna, Vienna 1010, Austria.; Research Institute of Physics, Southern Federal University, Rostov-on-Don 344006, Russia.
authors.forename: Eduard I
authors.initials: EI
authors.lastname: Vorobyov
authors.affiliation: National Astronomical Observatory of Japan, Tokyo 181-8588, Japan.
authors.forename: Tae-Soo
authors.initials: TS
authors.lastname: Pyo
authors.affiliation: National Astronomical Observatory of Japan, Tokyo 181-8588, Japan.
authors.forename: Misato
authors.initials: M
authors.lastname: Fukagawa
authors.affiliation: National Astronomical Observatory of Japan, Tokyo 181-8588, Japan.; University of Tokyo, Tokyo 113-8654, Japan.
authors.forename: Motohide
authors.initials: M
authors.lastname: Tamura
authors.affiliation: Max-Planck-Institut für Astronomie, Heidelberg 69117, Germany.
authors.forename: Thomas
authors.identifier: 0000-0002-1493-300X
authors.initials: T
authors.lastname: Henning
authors.affiliation: Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA.
authors.forename: Michael M
authors.initials: MM
authors.lastname: Dunham
authors.affiliation: Academia Sinica Institute of Astronomy and Astrophysics, Taipei 10617, Taiwan.
authors.forename: Jennifer L
authors.identifier: 0000-0003-3095-4772
authors.initials: JL
authors.lastname: Karr
authors.affiliation: National Astronomical Observatory of Japan, Tokyo 181-8588, Japan.
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Kusakabe
authors.affiliation: College of Science, Ibaraki University, Mito 310-0056, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Tsuribe
keywords: Astronomy; circumstellar arms and arcs; disk formation phase; stars; young stars