Asteroid Ryugu before the Hayabusa2 encounter

Progress in Earth and Planetary Science

Table 5 Small bodies for which boulder counts have been made from spacecraft images. The minimum boulder sizes measured are directly related to the best image resolution available for a given object

Name	Mean diameter (km)	Spectral type	Min boulder size of global count (m)	Min boulder size of regional count (m)	Power law found	Data source	References
Eros	17	S	15	0.05	− 3.2 as low as − 2.3 locally	NEAR	Rodgers et al. 2016; Thomas et al. 2001
Itokawa	0.35	S	6	0.1	− 3.1 − 3.5 as low as − 1.7 or as high as − 4.1 locally	Hayabusa	Mazrouei et al. 2014; Michikami et al. 2008; Noviello et al. 2014; Rodgers et al. 2016 Tancredi et al. 2015
Toutatis	2.9	S	n/a	10	− 4.4 locally	Chang’e 2	Jiang et al. 2015; Huang et al. 2013
Lutetia	99	M	n/a	60	− 5.0	Rosetta	Küppers et al. 2012; Sierks et al. 2011
Ida	32	S	n/a	45	n/a	Galileo	Lee et al. 1996
Phobos	22	D	n/a	5	− 3.2	Viking MGS MEX MRO	Ernst et al. 2015; Rodgers et al. 2016; Thomas et al. 2000
Deimos	12	D	n/a	~ 4	− 3.2	Viking	Lee et al. 1986; C. Ernst, personal communication
Churyumov-Gerasimenko	4	Comet	7	2	− 3.6 global; local ranges − 2.2 to − 4.0	Rosetta	Pajola et al. 2015, 2016