UTAPwiki/セミナー/宇宙物理学セミナー

Speaker 1: Yuting Lu

Title: Measuring Stellar Rotation Periods and Stellar Inclinations of Kepler Solar-type Stars

Abstract:
Spin-orbit angle, the angle between the stellar rotation spin and planetary orbital axis, has been an important indicator of the formation and evolution of exoplanetary systems. Unlike our solar system, large spin-orbit angles are observed in some hot Jupiter systems. To understand the origin of such large misalignment, more observations are required for different type of systems. Kepler telescope provides high quality photometric data for a large number of stars, which allows us to put constraints on spin-orbit angles for more systems by measuring the stellar inclination of their host star. In this presentation, I will first introduce current problem encountered in the estimation of stellar inclinations using asteroseismology. Then, I will discuss about several possible attempts to improve the measurement.

Speaker 2: Koki Tokeshi (n.b. slides and oral presentation will be in Japanese)

Title: Towards the resolution of uncertainty and refinement of the primordial black hole mass function

Abstract:
As my mock master defence, I will report two results around the peak counting theory. One is on the completely, locally and spherically symmetric perturbations in the peak counting theory, in which the predicted PBH abundance becomes larger compared to that of the conventional formulation. The other is on the refined version of the peak counting theory, in which the one-to-one correspondence among the mass, formation time, and the smoothing scale of PBHs is implemented, with the investigation of the choice of the window function, leading to the result that almost no correction is observed around the typical scale. The first topic was ongoing in my first talk on 19/11/2020 but this time the result is included, while there is almost no update on the second subject.


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Last-modified: 2021-01-20 (水) 19:04:20 (92d)