Amateur telescopes discover a kilometre-sized Kuiper belt object from stellar occultation

Abstract

Kuiper belt objects (KBOs) are thought to be the remnant of the early solar system, and their size distribution provides an opportunity to explore the formation and evolution of the outer solar system. In particular, the size distribution of kilometre-sized (radius = 1-10 km) KBO represents a signature of initial planetesimal sizes when planets form. These kilometre-sized KBOs are extremely faint, and it is impossible to detect them directly. Instead, monitoring of stellar occultation events is one possible way to discover these small KBOs. Hitherto, however, there has been no observational evidence for the occultation events by 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 $\sim$1.3 km, which is simultaneously provided by two low-cost small telescopes coupled with commercial CMOS cameras. From this detection, we conclude that a surface number density of KBOs with radii exceeding $\sim 1.2$ km is $\sim 6\times 10^5\mathrm{de}{\mathrm{g}}^{-2}$. This surface number density favours a theoretical size distribution model with an excess signature at a radius of 1-2 km. If this is a true detection, this implies that planetesimals before their runaway growth phase grow into kilometre-sized objects in the primordial outer solar system and remain as a major population of the present-day Kuiper belt.

23 pages, 10 figures, author final submission version, published in Nature Astronomy on 28 January 2019 (free version: https://rdcu.be/biPGW)

References in corpus (6)

• New Grids of ATLAS9 Model Atmospheres
• The Scattered Disk as the source of the Jupiter Family comets
• The Kuiper Belt Luminosity Function from m(R)=21 to 26
• Detectability of Occultation of Stars by Objects in the Kuiper Belt and Oort Cloud
• First Results From The Taiwanese-American Occultation Survey (TAOS)
• Organized Autotelescopes for Serendipitous Event Survey (OASES): design and performance

Cited by in corpus (10)

• A re-assessment of the Kuiper belt size distribution for sub-kilometer objects, revealing collisional equilibrium at small sizes
• On the Anomalous Acceleration of 1I/2017 U1 `Oumuamua
• Evidence for a rapid decrease in Pluto's atmospheric pressure revealed by a stellar occultation in 2019
• New constraint on the atmosphere of (50000) Quaoar from a stellar occultation
• Detectability of optical transients with timescales of sub-seconds
• The Case for a Large-Scale Occultation Network
• Detecting Interstellar Objects Through Stellar Occultations
• CHIMERA Occultation Constraints on the Abundance of Kilometer-scale Kuiper Belt Objects
• Modelling the optical energy profile of the 2021 October Jupiter impact flash
• Cloud reflection modelling for impact flashes on Jupiter: A new constraint on the bulk properties of the impact objects