宇宙科学談話会

ISAS Space Science Colloquium & Space Science Seminar

FY2019

日本語

国際協力を基軸に(国内計画との調和で)推進する核融合研究の現状について

栗原 研一(Kenichi KURIHARA)
国立研究開発法人 量子科学技術研究開発機構 核融合エネルギー研究開発部門 那珂核融合研究所

Place: A 2F Conf. room(1236) / A棟2階会議場(1236号室)

ENGLISH

Radio interferometer observations of the nearest high-mass young stellar object in the Orion Nebula

廣田 朋也(Tomoya HIROTA)
国立天文台水沢VLBI観測所

The Orion Nebula is known as the nearest (420 pc from the Sun) site of active high-mass star-formation. In particular, a bright infrared nebula called Kleinmann-Low object located at its central region has been extensively observed as the best laboratory for high-mass star-formation studies at the highest spatial resolution achievable with various astronomical instruments. Here we report recent observational results for one of the high-mass young stellar objects (HM-YSOs), radio source I, by using VERA (VLBI Exploration of Radio Astrometry) and ALMA (Atacama Large Millimeter/Submillimeter Array). We will discuss formation processes of this HM-YSO through dynamical properties of circumstellar disk and outflow driven by the magneto-centrifugal disk wind traced by centimeter/millimeter/submillimeter H2O and SiO maser lines.

Place: A 2F Conf. room(1236) / A棟2階会議場(1236号室)

日本語

「あかり」近赤外線分光観測による小惑星の含水鉱物探査

臼井 文彦(Fumihiko USUI)
神戸大学大学院理学研究科 惑星科学研究センター

小惑星における含水鉱物の存在を調べることは、太陽系の成り立ち、特に熱的な変遷を知る上で重要である。含水鉱物は液体の水と無水鉱物が反応して生成されるが、水の昇華温度以上でも比較的安定であるため、水の存在を示す重要なトレーサーである。含水鉱物は近赤外線の波長2.7 um付近に吸収フィーチャーを持つことが知られているが、この波長域は地球大気の吸収のために、地上望遠鏡では観測できていなかった。我々は赤外線天文衛星「あかり」を用いて、地球大気に影響されることなく小惑星の近赤外線分光観測を行い、小惑星66天体のスペクトルを得ることに成功した。その結果、多くのC型小惑星には含水鉱物に起因する顕著な吸収が見られること、一方ほとんどのS型小惑星にはそのような吸収が見られないことがわかった。本講演では、「あかり」による小惑星の近赤外線分光観測の概要とその結果から考えられる小惑星の形成進化過程について紹介し、さらに天文観測と小惑星探査の関係性について議論する。

Place: A 2F Conf. room(1236) / A棟2階会議場(1236号室)

ENGLISH

Laboratory astrophysics with electron beam ion traps

J. R. Crespo López-Urrutia
Max-Planck-Instutite fuer Kernphysik

At very high temperatures, atomic physics becomes the physics of highly charged ions (HCI). The presence of a few, still bound, electrons makes HCI from'metals'efficient absorbers and emitters of X rays, EUV, VUV and optical photons. Clear spectroscopic signatures from HCI are identifiably even at locations where the dominant light chemical elements are fully stripped, such as in AGN. Within the radiative zones of stars, HCI have a dominant contribution to the opacity. Future X-ray missions will provide unprecedented amounts of high-resolution spectral data. This will challenge our current atomic physics modelling of HCI, which is still limited by theoretical uncertainties and a lack of laboratory benchmarks for spectral models. Presently, existing laboratory data show clear disagreements with widely used astrophysical codes, call-ing for updating models. At the same time, the further development of atomic structure theory needed to generate data on collisional excitation and recombination, as well as photon-driven processes in astrophysical plasmas benefits from laboratory studies of HCI. Improving such benchmark measurements is an important task, ahead of the upcoming XRISM Resolve, Athena and Arcus missions. Electron beam ion traps (EBITs) are compact devices that produce, trap and excite HCI from N3+ (N IV) to U91+ (U XLII) under well-defined, steady-state conditions of charge state as well as excitation by a monoenergetic electron beam. They are sources for high-resolution spec-troscopy in all photon energy ranges. Dielectronic recombination, electron-impact excitation, and charge exchange are studied in detail using them.
Together with free-electron lasers and synchrotron radiation sources, EBITs have enabled soft X-ray laser spectroscopy, reaching by now up to the K-shell transitions of heavy elements.

4/9 14:00-17:00: Tutorial(1)
4/10 9:30-12:30: Tutorial(2)
4/10 14:00-16:00: Free discussion
(Room: Research and Administration Building , 6F, 1639)

 

実験室宇宙物理学の世界的拠点であるマックスプランク核物理学研究所において研究グループを率いるJose Crespo López-Urrutia氏より、電子ビームイオントラップ(EBIT)を用いたプラズマ実験の最先端を紹介いただきます。 また来所に合わせて2日間に渡るレクチャーを以下のスケジュールで行います。 ご都合のつく方はこちらも合わせてご参加ください。

4/9 14:00-17:00: Tutorial(1)
4/10 9:30-12:30: Tutorial(2)
4/10 14:00-16:00: Free discussion
(Room: Research and Administration Building , 6F, 1639)

Place: Shin-A 2F Conf. room A (1257) / 新A棟2階会議室A(1257号室)