报告题目：Astrometry for exoplanet search and SUSI

　　报告人：  Yitping Kok (University of Sydney)

　　时  间：  2012年12月10日（星期一）下午2：00

　　地  点：  南京天光所办公实验大楼四楼会议室

　　Abstract:

　　Ever since the discovery of the first exoplanet around a main-sequence star, the radial

　　velocity (RV) technique has become the workhorse of exoplanetary detection. The recent

　　discovery of an Earth size planet around a component of the nearest stellar system, α Cen

　　B, at RV of ~0.5m/s demonstrates the exquisite sensitivity this technique can now achieve.

　　Despite this maturity, it is insensitive for detecting planets around intermediate mass

　　(IM) stars which mostly exhibit A/B-type spectra (Galland et al., 2005). Statistics of

　　planets detected around evolved lower-mass IM stars show that these planets have larger

　　minimum masses and semi-major axes as well as a higher occurrence rate of giant planets, 9

　　-27% (Bowler et al., 2010; Johnson et al., 2010; Lovis et al., 2007), compared to Sun-like

　　stars, 6% (Bonavita et al., 2007). This supports the idea that planetary formation is more

　　efficient around higher mass stars (Kennedy & Kenyon, 2008). In order to directly search

　　for planets around IM stars, alternate techniques must be used. Direct imaging, which is

　　fundamentally limited by the large contrast ratio between star and planet, attains its

　　highest sensitivity for hot young planets at distances far (5AU) from their host stars. The

　　best, still under-utilized, method to search for planets, particularly giant ones, within a

　　20AU radius around IM stars is high precision astrometry. In this talk I will introduce the

　　principle behind the technique and efforts being pursued by the international astronomical

　　community, especially at the Sydney University Stellar Interferometer (SUSI), in this field

　　of research.

南京天文光学技术研究所学术委员会　 

2012年12月7日