Irregular moons of Saturn -- Fenrir

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

23 Oct 2018 / TD


	Overview Table
Moon name	Fenrir
Saturn range	22e6	km
Orbit period	3.5	years
Orbit direction	retrograde
Size ~	4	km
Rotation period	unknown
Discovery year	2004

(A)	Designations and discovery circumstances
(A1)	Moon name	Fenrir
(A2)	Moon abbrev. (TD)	Fen
(A3)	IAU number	Saturn XLI
(A4)	Provisional designation	S/2004 S 16
(A5)	SPICE ID	641
(A6)	Also-used label	S41
(A7)	First observation date	13 Dec 2004
(A7)	Announcement date	04 May 2005
(A7)	IAU circular announcement no.	8523
(A8)	Discoverers	Jewitt, et al.

(B)	Orbit parameters
(B1)	Orbit direction	retrograde
(B2)	Group member	Norse
(B3)	Dynamical family	Ymir
(B4)	Periapsis range	19.43e6	km
(B5)	Semi-major axis	22.45e6	km
(B6)	Apoapsis range	25.47e6	km
(B7)	Semi-major axis	372	R_Saturn
(B8)	Semi-major axis	0.150	au
(B9)	Semi-major axis	0.34	R_Hill
(B10)	Orbit eccentricity	0.13	
(B11)	Orbit inclination	165.0	°
(B12)	Inclination supplemental angle	15.0	°
(B13)	Orbital period	1260	d
(B14)	Orbital period	3	5	1.75	y:m:w
(B15)	Mean orbit velocity	1.30	km/s

(C)	Physical parameters
(C1)	Mean size ~	4	-0.5	+1	km
(C2)	Mean radius ~	1.8	km
(C3)	Equatorial circumference ~	12	km
(C4)	Minimum equatorial axes ratio	unknown
(C5)	Axes radii (a x b x c) ~	unknown
(C5)	
(C6)	Mass ~	1e13	kg
(C7)	Mean density (?)	0.5	g/cm^3
(C8)	Surface escape velocity ~	2	km/h
(C9)	Rotation period	unknown	
(C9)	Rotation period error	--
(C9)	Spin rate	unknown
(C10)	Spin direction	unknown
(C11)	Seasons	unknown
(C12)	Pole direction (ecliptic longitude λ)	unknown
(C12)	Pole direction (ecliptic latitude β)	unknown
(C13)	Pole direction (geocentric RA)	unknown
(C13)	Pole direction (geocentric Dec)	unknown
(C14)	Absolute visual magnitude ~	15.9	mag
(C15)	Apparent visual magnitude from Earth	25.0	mag
(C16)	Best apparent magnitude for Cassini	17.0	mag
(C17)	Spectral slope	unknown
(C17)	B-R color index	unknown
(C18)	Albedo (?)	0.06	
(C19)	Hill sphere radius ~	380	km
(C20)	Hill sphere radius ~	205	r_Fen