Spectral Type and Geometric Albedo of (98943) 2001 CC21, the Hayabusa2# Mission Target

We conducted optical polarimetry and near-infrared spectroscopy of JAXA's Hayabusa2# mission target, (98943) 2001 CC21, in early 2023. Our new observations indicated that this asteroid has a polarimetric inversion angle of ~21 deg, absorption bands around 0.9 and 1.9 um, and a geometric albedo of 0.285 +- 0.083. All these features are consistent with those of S-type but inconsistent with L-type. Based on this evidence, we conclude that JAXA's Hayabusa2# spacecraft will explore an S-type asteroid with albedo and size (0.42-0.56 km when we assume the absolute magnitude of 18.6) similar to (25143) Itokawa.Comment: 5 pages, 3 figures, Submitted to MNRAS Letter on 2023 April

Measurment and analysis of unconfined groundwater quality in the alluvial fan of Koto river

Contamination of unconfined groundwater by nitrate nitrogen has been reported at several locations in the Takamatsu plain. To understand the mechanism and the extent of groundwater contamination, a target region in the plain was selected where the nitrate nitrogen has shown high concentration throughout the year. Intensive field measurement of groundwater level, EC, pH and the analysis of major ions in the groundwater were performed seven times in 2004 at twenty four shallow wells. The rate of stable isotope of nitrogen was also analyzed at two different seasons. The obtained data clarified that the nitrogen in the unconfined groundwater from the ground surface has been not only inorganic nitrogen but organic. It was also indicated that the fertilizer in the greenhouses for vegetables and waste water from a cow barn in the target area have been the major sources of the nitrogen