Size Constraint on Hayabusa2 Extended Mission Rendezvous Target 1998 KY26 via VLT/VISIR Nondetection
1998 KY _26 is a tiny near-Earth asteroid ( H = 26.1) discovered in 1998. It has been selected as the target of the Hayabusa2 extended mission, which will rendezvous with 1998 KY _26 in 2031. However, one of the most basic physical properties, size, remains poorly constrained, posing potential chall...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2025-01-01
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| Series: | The Astronomical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-3881/adc682 |
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| Summary: | 1998 KY _26 is a tiny near-Earth asteroid ( H = 26.1) discovered in 1998. It has been selected as the target of the Hayabusa2 extended mission, which will rendezvous with 1998 KY _26 in 2031. However, one of the most basic physical properties, size, remains poorly constrained, posing potential challenges for spacecraft operations. We aimed at constraining the size of 1998 KY _26 by means of thermal infrared observations. We performed thermal infrared observations of 1998 KY _26 using the ESO Very Large Telescope/VISIR on three consecutive nights in 2024 May. After stacking all frames, we find no apparent detection of 1998 KY _26 on the resulting images. The upper-limit flux density of 1998 KY _26 is derived as 2 mJy at 10.64 μ m. From this upper-limit flux density obtained via non-detection, we conclude that the diameter of 1998 KY _26 is smaller than 17 m with thermophysical modeling. This upper limit size is smaller than the radar derived 30 (±10) m. Our size constraint on 1998 KY _26 is essential for the operation of the Hayabusa2 spacecraft during proximity operations using remote sensing instruments as well as a possible impact experiment using the remaining projectile. |
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| ISSN: | 1538-3881 |