TY - JOUR
T1 - A kilometre-sized Kuiper belt object discovered by stellar occultation using amateur telescopes
AU - Arimatsu, K.
AU - Tsumura, K.
AU - Usui, F.
AU - Shinnaka, Y.
AU - Ichikawa, K.
AU - Ootsubo, T.
AU - Kotani, T.
AU - Wada, T.
AU - Nagase, K.
AU - Watanabe, J.
N1 - Funding Information:
We thank the personnel of the Miyakojima City Museum and Miyako open-air school (Miyako Seishonen no Ie) for providing site infrastructure and access to facilities. We also thank the people of Miyako Island for supporting our observations. We thank Y. Sarugaku for constructive advice. This research has been partly supported by JSPS grants (JP26247074, 15J10278, 15J10864, 26800112, 16K17796, 18K13584 and 18K13606).
Publisher Copyright:
© 2019, The Author(s), under exclusive licence to Springer Nature Limited.
PY - 2019/4/1
Y1 - 2019/4/1
N2 - Kuiper belt objects (KBOs) are thought to be remnants of the early Solar System, and their size distribution provides an opportunity to explore the formation and evolution of the outer Solar System 1–5 . In particular, the size distribution of kilometre-sized (radius = 1–10 km) KBOs represents a signature of initial planetesimal sizes when planets form 5 . These kilometre-sized KBOs are extremely faint, and it is impossible to detect them directly. Instead, the monitoring of stellar occultation events is one possible way to discover these small KBOs 6–9 . However, until now, there has been no observational evidence for occultation events of KBOs with radii of 1–10 km. Here, we report the first detection of a single occultation event candidate by a KBO with a radius of ~1.3 km, which was simultaneously provided by two low-cost small telescopes coupled with commercial complementary metal–oxide–semiconductor cameras. From this detection, we conclude that the surface number density of KBOs with radii exceeding ~1.2 km is ~6 × 10 5 deg −2 . This surface number density favours a theoretical size distribution model with an excess signature at a radius of 1–2 km (ref. 5 ). If this is a true KBO detection, this implies that planetesimals before their runaway growth phase grew into kilometre-sized objects in the primordial outer Solar System and remain as a major population in the present-day Kuiper belt.
AB - Kuiper belt objects (KBOs) are thought to be remnants of the early Solar System, and their size distribution provides an opportunity to explore the formation and evolution of the outer Solar System 1–5 . In particular, the size distribution of kilometre-sized (radius = 1–10 km) KBOs represents a signature of initial planetesimal sizes when planets form 5 . These kilometre-sized KBOs are extremely faint, and it is impossible to detect them directly. Instead, the monitoring of stellar occultation events is one possible way to discover these small KBOs 6–9 . However, until now, there has been no observational evidence for occultation events of KBOs with radii of 1–10 km. Here, we report the first detection of a single occultation event candidate by a KBO with a radius of ~1.3 km, which was simultaneously provided by two low-cost small telescopes coupled with commercial complementary metal–oxide–semiconductor cameras. From this detection, we conclude that the surface number density of KBOs with radii exceeding ~1.2 km is ~6 × 10 5 deg −2 . This surface number density favours a theoretical size distribution model with an excess signature at a radius of 1–2 km (ref. 5 ). If this is a true KBO detection, this implies that planetesimals before their runaway growth phase grew into kilometre-sized objects in the primordial outer Solar System and remain as a major population in the present-day Kuiper belt.
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U2 - 10.1038/s41550-018-0685-8
DO - 10.1038/s41550-018-0685-8
M3 - Letter
AN - SCOPUS:85064045430
SN - 2397-3366
VL - 3
SP - 301
EP - 306
JO - Nature Astronomy
JF - Nature Astronomy
IS - 4
ER -