Asteroid-Meteorite Reflectance Spectroscopy, Space Weathering, and Hayabusa Missions

Colloquium

Astronomy Colloquium (2017 Spring Semester)

* Date: Jun 16
* Speaker: Takahiro Hiroi (Brown University)
* Title: Asteroid-Meteorite Reflectance Spectroscopy, Space Weathering, and Hayabusa Missions
* Abstract

Asteroids, along with comets, are believed to be the remnant of the planetesimals and retain information of the distribution and evolution of solid materials of our solar system. Since 1970s, remote sensing of asteroids has been developing
from simple classification based on reflectance spectroscopy over the extended visible range to the near-infrared and infrared ranges. Early detection of the surface composition of the asteroid 4 Vesta as a basaltic composition similar to HED
meteorites was successful. However, a serious mismatch of reflectance spectra became obvious between the S-type asteroids and ordinary chondrites which occupy the majority of the inner main belt and meteorite population respectively. Although many
meteoriticists believed the mismatch was due to the presence of metallic iron, which disqualifies the S-type asteroids to be ordinary chondrites, less popular idea was that the difference was due to space weathering. The existence of space weathering
was recognized first with lunar soils, and the products were later microscopically discovered as nanophase metallic iron particles in the returned Apollo samples. The resolution of the space weathering debate had to wait until 2005 and 2010 when the
Japanese Hayabusa spacecraft rendez-voused with an S-type asteroid Itokawa and returned small particles. Three out of four tiny (about 0.1 mm) particles had nanophase iron and iron sulfide particles formed on or near the surface. Now Hayabusa 2 is
flying to a C-type asteroid Ryugu to rendez-vous with it in 2018 and return the samples in 2020. Along with the US OSIRIS-REx mission to a B-type asteroid Bennu, they will likely open a new era of study on asteroid-meteorite relationship and early
solar system materials.

Date	Speaker	Title	Remarks
Mar 02	Chris Belczynski (Warsaw University Observatory)	The ongoing LIGO search for gravitational-waves: BH-BH modeling
Mar 09	Jeongwoo Lee (Institute for Space-Earth Environmental Research, Nagoya University)	When the Sun’s Coronal Tail Wags Its Photospheric Dog
Mar 16	Hongjun An (CBNU)	High-energy astrophysics in the X-ray and GeV energies
Mar 23	KASI ALMA Group	ALMA Town Meeting
Mar 30	Ken Chen (NAOJ, Japan)	Lighting up the Universe with Extreme Supernovae
Apr 06	Guangyao Zhao (KASI)	Multi-frequency mm-VLBI observations of AGNs with KVN
Apr 11	Tarun Souradeep (IUCAA Pune, India)	Rugged but enigmatic post-Planck Cosmos	Tuesday
Apr 20	Tugca Sener (KASI)	Hot subdwarf stars in binaries
Apr 27	Benjamin L’Huillier (KASI)	Numerical simulations of structure formation: LCDM and beyond
May 04	TBD	TBD
May 11	Thiem Hoang (KASI)	New Insights into the Role and Importance of Interstellar Nanoparticles
May 18	Ho Jung Paik (U Maryland)	Superconducting Gravitational Wave Detector For Observation in Infrasound Frequency Band
May 23	Kwang-Ho Park (Georgia Tech)	Feedback-regulated fueling of massive black holes	Tuesday
May 25	Pei-Ying Hsieh (ASIAA)	The molecular gas feeding the Galactic center – an excellent laboratory to understand supermassive black hole feeding
May 30	Andreas Schulze (NAOJ)	New constraints on the black hole spin in radio-loud quasars	Tuesday
Jun 01	Mijin Yoon (Yonsei University)	Testing the statistical isotropy using dipolar modulation in galaxy number counts
Jun 08	Juan Carlos Algaba Marcos (KASI)	Exploring the variability of the flat spectrum radio source 1633+382
Jun 16	Takahiro Hiroi (Brown University)	Asteroid-Meteorite Reflectance Spectroscopy, Space Weathering, and Hayabusa Missions	Friday

2017 Spring semester detail