IRTF Data Archive Program Information

# # Program information file # PROGRAM_ID 2021A030 PROGRAM_TITLE Investigation of surface mineral distribution of [99942] Apophis PROGRAM_INV1 Hee-Jae Lee PROGRAM_INV2 Myung-Jin Kim PROGRAM_INV3 Dong-Heun Kim PROGRAM_INV4 Hong-Kyu Moon PROGRAM_INV5 Young-Jun Choi PROGRAM_SCICAT solar system PROGRAM_ABSTRACT_BEG We propose the time-series spectroscopic observation of [99942] Apophis using SpeX on March 2021 to investigate surface mineral distribution. Apophis is an Sq-type asteroid, which will approach the Earth within the geosynchronous orbit in April 2029. Apophis' Earth approach in 2029 will be an excellent opportunity to examine how the physical properties of the asteroid could be changed due to the Earth's gravitational perturbation. However, to do so, we need to understand Apophis' mineral distribution before the Earth approach, and the 2021 apparition of Apophis is the last chance to make such study. The surface mineralogical property of Sq-type asteroid strongly depends on olivine and pyroxene distributions, which can be well traced using their 1- and 2-micrometer absorption bands. Therefore, we plan to observe Apophis using the low-resolution prism mode of SpeX with the 0.8 x 15 arcsec slit to obtain 0.8-2.5 micrometer spectra. The K-band magnitude of Apophis is 14.7 mag during our observing period. We estimate that ~600 sec of integration time should be sufficient to achieve a signal-to-noise ratio of 100. We plan to map the surface mineral distribution using the spin period of Apophis is 30.56 hr. The 5 consecutive nights observation should ensure this mapping process, regardless of weather situations. Our results will provide an essential scientific background for Korean space mission design, as Apophis is target for Korean space mission [Apophis Rendezvous Mission for Year 29; ARMY29] planned by Korea Astronomy and Space Science Institute [KASI]. PROGRAM_ABSTRACT_END