Irregular moons of Saturn -- Ymir

For notes, see https://tilmanndenk.de/outersaturnianmoons/ymir/#1

22 Oct 2018 / TD


	Overview Table
Moon name	Ymir
Saturn range	23e6	km
Orbit period	3.6	years
Orbit direction	retrograde
Size ~	19	km
Rotation period	11	55	hh:mm
Discovery year	2000

(A)	Designations and discovery circumstances
(A1)	Moon name	Ymir
(A2)	Moon abbrev. (TD)	Ymi
(A3)	IAU number	Saturn XIX
(A4)	Provisional designation	S/2000 S 1
(A5)	SPICE ID	619
(A6)	Also-used label	S19
(A7)	First observation date	07 Aug 2000
(A7)	Announcement date	25 Oct 2000
(A7)	IAU circular announcement no.	7512
(A8)	Discoverers	Gladman B. et al.

(B)	Orbit parameters
(B1)	Orbit direction	retrograde
(B2)	Group member	Norse
(B3)	Dynamical family	Ymir
(B4)	Periapsis range	15.40e6	km
(B5)	Semi-major axis	23.13e6	km
(B6)	Apoapsis range	30.86e6	km
(B7)	Semi-major axis	383	R_Saturn
(B8)	Semi-major axis	0.155	au
(B9)	Semi-major axis	0.35	R_Hill
(B10)	Orbit eccentricity	0.33	
(B11)	Orbit inclination	173.5	°
(B12)	Inclination supplemental angle	6.5	°
(B13)	Orbital period	1316	d
(B14)	Orbital period	3	7	1	y:m:w
(B15)	Mean orbit velocity	1.28	km/s

(C)	Physical parameters
(C1)	Mean size ~	19	-3	+5	km
(C2)	Mean radius ~	9.6	km
(C3)	Equatorial circumference ~	65	km
(C4)	Minimum equatorial axes ratio	1.37
(C5)	Axes radii (a x b x c) ~	12	11	8	km
(C5)	Side lengths (equatorial cross-section) ~	25	24	20	km
(C6)	Mass ~	2e15	kg
(C7)	Mean density (?)	0.5	g/cm^3
(C8)	Surface escape velocity ~	13	km/h
(C9)	Rotation period (sidereal)	11.92220	h
(C9)	Rotation period error	0.00002	h
(C9)	Spin rate	2.01305	d^(-1)
(C10)	Spin direction	retrograde
(C11)	Seasons	none
(C12)	Pole direction (ecliptic longitude λ)	230	±20	°
(C12)	Pole direction (ecliptic latitude β)	-85	±10	°
(C13)	Pole direction (geocentric RA)	100	±20	°
(C13)	Pole direction (geocentric Dec)	-70	±10	°
(C14)	Absolute visual magnitude ~	12.3	mag
(C15)	Apparent visual magnitude from Earth	21.7	mag
(C16)	Best apparent magnitude for Cassini	13.2	mag
(C17)	Spectral slope ~	+8.1	%/100nm
(C17)	B-R color index ~	1.22	
(C18)	Albedo (?)	0.06	
(C19)	Hill sphere radius ~	1500	km
(C20)	Hill sphere radius ~	160	r_Ymi