Date & Time: 2025/July/17 17:00-18:00, Venue: Zoom TV Conference System. This is an informal seminar on the formation of stars and planets. We welcome anyone interested in the subject.
Abstract:
The magnetic fields in protoplanetary disks around young stars play an important role in disk evolution and planet formation. Dust polarization is the most reliable method to observe the magnetic field for star forming region since dust grains are aligned with magnetic field. However, in disks, it has been suggested that dust polarization is not always caused by magnetic field because scattering and other alignment mechanisms are effeicnt as dust grows. Here, we report multi-wavelength (0.87, 1.3, 2.1 and 2.7 mm) observations of polarized thermal emission in the protoplanetary disk around HD 142527, which shows a cresent dust distribution. We revealed that smaller dust particles still exhibit magnetic alignment in the southern part of the disk. Furthermore, angular offsets between the observed magnetic field and the disk azimuthal direction were discovered. These offsets can be used to measure the relative strengths of each component of a three-dimensional magnetic field (radial (Br), azimuthal (Bϕ) and vertical (Bz)). Applying this method, we derived the magnetic field around a 200 au radius from the protostar as ∣Br∣:∣Bϕ∣:∣Bz∣ ≈ 0.26:1:0.23 with a strength of ~ 0.3 mG. Our observations provide some key parameters of magnetic activities, including the plasma beta of 0.02. These conditions imply that the observed highly turbulence will be caused by MRI.
他、会議報告、速報など、飛び入りも歓迎します。今回もしくは次回以降、話題提供できる方は世話人までメールしていただけましたら幸いです。
Participants:40, Affiliations:14
Participants list:
ASIAA PD Yuya Fukuhara
Ibaraki P Toru Tsuribe, D2 Ren Moriizumi
Ibaraki/NAOJ P Munetake Momose
JAMSTEC R Sota Arakawa
Kagoshima D3 Miyu Kido
Kyoto M1 Hiroto Nakasone
Kyushu PD Jihye Hwang, D2 Ayumu Shoshi, D1 Mitsuki Omura, M1 Takehiro Tsugeki
Musashino Univ. AP Aya Higuchi
Nagoya P Shu-ichiro Inutsuka, PD Kanta Kitajima, D2 Riona Yamada, D2 Izumi Seno, D1 Kenshin Onogawa, M2 Yuji Miko, M2 Hayato Shimizu, M2 Kota Kobayashi, M2 Shusuke Utsumi, M1 Taisei Shioya, M1 Kanaho Imata, M1 Kohsei Nozaki, M1 Asai Akihito
NAOJ D3 Tomohiro Yoshida, M2 Naoya Kitade
NDA A Kenji Kurosaki
RIKEN PD Haruka Washinoue, PD Yoshihide Yamato
Science Tokyo PD Ryosuke Tominaga, D1 Ryo Kato, M2 Haruto Oshiro
Shiga medical AP Kazutaka Motoyama
UTokyo P Takeru Suzuki, P Yuri Aikawa, A Satoshi Ohashi, PD Naoto Harada, PD Ryuta Orihara, D2 Yuto Komichi
次回：2025/October/9 17:00-
連絡世話人：冨永遼佑（東京科学大学） tominaga.r.aa[at]m.titech.ac.jp