A kilometre-sized Kuiper belt object discovered by stellar occultation using amateur telescopes

Arimatsu, Ko; Tsumura, Kohji; Usui, Fumihiko; Shinnaka, Yoshiharu; Ichikawa, Kohei; Ootsubo, Takafumi; Kotani, Takayuki; Wada, Takehiko; Nagase, Koichi; Watanabe, Jun

doi:10.1038/s41550-018-0685-8

Cited by 66 publications

(42 citation statements)

References 30 publications

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“…In the Kuiper belt, the size distribution has a similar shape as predicted by simulations that include the streaming instability between 10 and 100 km (Schäfer et al 2017), which indicates large initial sizes. On the other hand, recent discoveries of Kuiper belt objects through stellar occultations rather indicate a size of 1-2 km (Arimatsu et al 2019). Small initial sizes of 0.4-4 km have also been inferred theoretically by Schlichting et al (2013).…”

Section: Introductionmentioning

confidence: 92%

Effect of pebble flux-regulated planetesimal formation on giant planet formation

Voelkel

Klahr

Mordasini

et al. 2020

A&A

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Context. The formation of gas giant planets by the accretion of 100 km diameter planetesimals is often thought to be inefficient. A diameter of this size is typical for planetesimals and results from self-gravity. Many models therefore use small kilometer-sized planetesimals, or invoke the accretion of pebbles. Furthermore, models based on planetesimal accretion often use the ad hoc assumption of planetesimals that are distributed radially in a minimum-mass solar-nebula way. Aims. We use a dynamical model for planetesimal formation to investigate the effect of various initial radial density distributions on the resulting planet population. In doing so, we highlight the directive role of the early stages of dust evolution into pebbles and planetesimals in the circumstellar disk on the subsequent planet formation. Methods. We implemented a two-population model for solid evolution and a pebble flux-regulated model for planetesimal formation in our global model for planet population synthesis. This framework was used to study the global effect of planetesimal formation on planet formation. As reference, we compared our dynamically formed planetesimal surface densities with ad hoc set distributions of different radial density slopes of planetesimals. Results. Even though required, it is not the total planetesimal disk mass alone, but the planetesimal surface density slope and subsequently the formation mechanism of planetesimals that enables planetary growth through planetesimal accretion. Highly condensed regions of only 100 km sized planetesimals in the inner regions of circumstellar disks can lead to gas giant growth. Conclusions. Pebble flux-regulated planetesimal formation strongly boosts planet formation even when the planetesimals to be accreted are 100 km in size because it is a highly effective mechanism for creating a steep planetesimal density profile. We find that this leads to the formation of giant planets inside 1 au already by pure 100 km planetesimal accretion. Eventually, adding pebble accretion regulated by pebble flux and planetesimal-based embryo formation as well will further complement this picture.

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Section: Introductionmentioning

confidence: 92%

Effect of pebble flux-regulated planetesimal formation on giant planet formation

Voelkel

Klahr

Mordasini

et al. 2020

A&A

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“…High-sensitivity and high-cadence observations with CMOS cameras mounted on ∼ meter class telescopes will become more important to observe occultation events of fainter stars (with magnitudes fainter than ∼15, e.g., Arimatsu et al 2019a), which occur more frequently than those of brighter stars. Observations with airborne telescopes such as SOFIA (Person 2012) and with portable telescope systems for high-cadence observations (e.g., Arimatsu et al 2017Arimatsu et al , 2019b will also be useful to observe rare and local occultation events.…”

Section: Conclusion and Future Prospectsmentioning

confidence: 99%

Evidence for a rapid decrease of Pluto’s atmospheric pressure revealed by a stellar occultation in 2019

Arimatsu

Hashimoto

Kagitani

et al. 2020

A&A

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We report observations of a stellar occultation by Pluto on 2019 July 17. A single-chord high-speed (time resolution = 2 s) photometry dataset was obtained with a CMOS camera mounted on the Tohoku University 60 cm telescope (Haleakala, Hawaii). The occultation light curve is satisfactorily fitted to an existing atmospheric model of Pluto. We find the lowest pressure value at a reference radius of r = 1215 km among those reported after 2012. These reports indicate a possible rapid (approximately 21−5+4% of the previous value) pressure drop between 2016, which is the latest reported estimate, and 2019. However, this drop is detected at a 2.4σ level only and still requires confirmation from future observations. If real, this trend is opposite from the monotonic increase of Pluto’s atmospheric pressure reported by previous studies. The observed decrease trend is possibly caused by ongoing N2 condensation processes in the Sputnik Planitia glacier associated with an orbitally driven decline of solar insolation, as predicted by previous theoretical models. However, the observed amplitude of the pressure decrease is larger than the model predictions.

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“…Transient diffraction patterns caused by the occultation of a distant star due to an intervening small body have been proposed and used to search for Kuiper Belt objects (KBOs) and Oort Cloud objects (OCOs) in the Solar System (Bailey 1976;Dyson 1992;Roques & Moncuquet 2000;Nihei et al 2007;Schlichting et al 2009Schlichting et al , 2012Arimatsu et al 2019). Here, we propose an analagous search for interstellar objects (ISOs), flagged by their unusual inclinations and unique kinematics leading a distribution of characteristic distribution of durations, the peak of which lies between that of Kuiper belt objects and that of Oort cloud objects.…”

Section: Introductionmentioning

confidence: 99%

Detecting Interstellar Objects through Stellar Occultations

Siraj

Loeb

2020

ApJL

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Stellar occultations have been used to search for Kuiper Belt and Oort Cloud objects. We propose a search for interstellar objects based on the characteristic durations (∼ 0.1s) of their stellar occultation signals and high inclination relative to the ecliptic plane. An all-sky monitoring program of all ∼ 7×10 6 stars with R 12.5 using 1-m telescopes with 0.1 s cadences is predicted to discover ∼ 1 interstellar object per year.

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A kilometre-sized Kuiper belt object discovered by stellar occultation using amateur telescopes

Cited by 66 publications

References 30 publications

Effect of pebble flux-regulated planetesimal formation on giant planet formation

Effect of pebble flux-regulated planetesimal formation on giant planet formation

Evidence for a rapid decrease of Pluto’s atmospheric pressure revealed by a stellar occultation in 2019

Detecting Interstellar Objects through Stellar Occultations

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