Planet のバックアップ(No.42)

惑星セミナー2018 †

惑星セミナーは原則として毎週木曜日の14:00から理論部セミナー室で開催しています。
astro-phセミナーは毎週金曜日の12:30から理論部セミナー室で開催しています。

Schedule & History †

2017年度 2016年度 2015年度 2014年度

日程	発表	タイトル	Remarks
前期第1回 5/17 15:00-	荻原正博	Formation of the terrestrial planets in the solar system around 1 au via radial concentration of planetesimals	15:00
前期第2回 5/24 15:00-	波々伯部広隆	Determination of outer edge of circumplanetary disk in local 3d hydrodynamic simulations	15:00
前期第3回 5/30 14:00-	Dimitri Veras	The growing field of post-main-sequence exoplanetary science, with strong connections to the solar system	Wednesday@Rinko room
前期第4回 6/14 14:00-	細野七月	Numerical simulations of the giant impact onto the magma ocean
前期第5回 6/28 14:00-	兵頭龍樹	On the origin of Phobos and Deimos
前期第6回 7/12 14:00-	樋口有理可	Inner solar system objects with hyperbolic orbits: Interstellar origin or Oort cloud comets?
前期第7回 7/19 14:00-	中野龍之介	中心星質量による原始惑星系円盤進化の変化
前期第8回 7/26 14:00-	中嶋彩乃	Orbital evolution of Saturn's mid-sized moons and the tidal heating of Enceladus
後期第1回 9/19 14:00-	波々伯部広隆	論文紹介 (Tanigawa et al. 2012, ApJ, Distribution of Accreting Gas and Angular Momentum onto Circumplanetary Disks)
後期第2回 10/3 14:00-	小久保英一郎	Planetesimal Formation by Gravitational Instability of a Porous Dust Disk
後期第3回 10/24 14:00-	瀧哲朗	Chondrule Survivability in the Protosolar disk
後期第4回 10/31 13:00-	Jason Man Yin Woo	The curious case of Mars' formation	13:00
後期第5回 11/7 14:00-	松本侑士	TBA
後期第6回 11/21 14:00-	藤井悠里	TBA

5/30 Dimitri Veras, The growing field of post-main-sequence exoplanetary science, with strong connections to the solar system: The quest for identifying the bulk chemical composition of extrasolar planets and robust observational evidence that between 25% and 50% of all Milky Way white dwarfs host currently dynamically-active planetary systems motivate investigations that link their formation and fate. Here I provide a review of our current knowledge of these systems, including an update on the observational and theoretical aspects of the groundbreaking discovery of at least one disintegrating minor planet transiting white dwarf WD 1145+017. I show how this field incorporates several facets of solar system physics and chemistry, and how its interdisciplinary nature requires input from orbital dynamics, stellar evolution, astrochemistry, atmospheric science and surface processes.

10/31 Jason Woo, The curious case of Mars' formation: Dynamical models of planet formation coupled with cosmochemical data from martian meteorites show that Mars' isotopic composition is distinct from that of Earth. Reconciliation of formation models with meteorite data require that Mars grew further from the Sun than its present position. Here, we evaluate this compositional difference in more detail by comparing output from two N-body planet formation models. The first of these planet formation models simulates what is termed the `Classical' case wherein Jupiter and Saturn are kept in their current orbits. We compare these results with another model based on the `Grand Tack', in which Jupiter and Saturn migrate through the primordial asteroid belt. Our estimate of the average fraction of chondrite assembled into Earth and Mars assumes that the initial solid disk consists of only sources of enstatite chondrite composition in the inner region, and ordinary chondrite in the outer region. Results of these analyses show that both models tend to yield Earth and Mars analogues whose accretion zones overlap. The Classical case fares better in forming Mars with its documented composition (29% to 68% enstatite chondrite plus 32% to 67% ordinary chondrite) though the Mars analogues are generally too massive. We also further calculate the isotopic composition of 17O, 50Ti, 54Cr, 142Nd, 64Ni, and 92Mo in the martian mantle from the Grand Tack simulations. We find that it is possible to match the calculated isotopic composition of all the above elements in Mars' mantle with their measured values, but the resulting uncertainties are too large to place good restriction on the early dynamical evolution and birth place of Mars.