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東京大学・天文学教育研究センターでは2003年4月から談話会を開いています。
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ML: semiadm _at_ ioa.s.u-tokyo.ac.jp
please replace _at_ with @
Language: English
Abstract: Intense mass loss at the red supergiant phase is crucial for better understanding the evolution of massive stars, particularly given that very early-phase spectra of supernovae (SNe) suggest significant increases in mass loss just before the SN explosion. WOH G64 is a rare, heavily dust-enshrouded red supergiant in the Large Magellanic Cloud (LMC) -- the brightest in the mid-IR in the LMC. We present milliarcsecond-resolution near-IR (2.0--2.45 micron) interferometric imaging of WOH G64 with the GRAVITY instrument at ESO's Very Large Telescope Interferometer (VLTI) -- the first close-up image of an individual star outside the Milky Way. The observed image reveals an elliptical ring-like structure and more compact, elongated inner emission with a size of ~4 x 2 mas. This elongated emission can be interpreted as a bipolar outflow or alternatively as a circumstellar envelope elongated due to a putative companion. Furthermore, based on our visible and near-IR photometric monitoring with the Rapid Eye Mount Telescope at La Silla since 2023 and the archival data, we found that a significant increase in the circumstellar dust should have started at some point between 2006 and 2016, perhaps due to episodic dust formation. Interestingly, another recent study reveals that the central star evolved from a red supergiant (3200 K) to a yellow hypergiant (4700 K) in 2014 within a year without an outburst or eruptive event. We will discuss ongoing and future observations to understand this unique object that provides a rare opportunity to witness the evolution of a massive star in real time and study the physics of the extreme mass loss.
| # | Date | Speaker | Title | Chair |
| 430 | 2025年7月24日(木) 15:30-16:30 | Keiichi Ohnaka (Universidad Andrés Bello) | Milliarcsecond-resolution near-infrared interferometric imaging of the rapidly changing red supergiant WOH G64 in the Large Magellanic Cloud | I.Sakon |
詳細はこちら: 令和7(2025)年度談話会
| # | Date | Speaker | Title | Chair |
| 429 | 2025年4月17日(木) 15:30-16:30 | Eduardo Ibar (Universidad de Valparaíso) | The properties of emitting line galaxies discovered by the JWST Emission Line Survey (JELS) | I.Sakon |
