Irregular moons of Saturn -- Hyrrokkin

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

23 Oct 2018 / TD


	Overview Table
Moon name	Hyrrokkin
Saturn range	18e6	km
Orbit period	2.6	years
Orbit direction	retrograde
Size ~	8	km
Rotation period	12	45	hh:mm
Discovery year	2006

(A)	Designations and discovery circumstances
(A1)	Moon name	Hyrrokkin
(A2)	Moon abbrev. (TD)	Hyr
(A3)	IAU number	Saturn XLIV
(A4)	Provisional designation	S/2004 S 19
(A5)	SPICE ID	644
(A6)	Also-used label	S44
(A7)	First observation date	12 Dec 2004
(A7)	Announcement date	30 Jun 2006
(A7)	IAU circular announcement no.	8727
(A8)	Discoverers	Sheppard S. et al.

(B)	Orbit parameters
(B1)	Orbit direction	retrograde
(B2)	Group member	Norse
(B3)	Dynamical family	Hyrrokkin/Greip ?
(B4)	Periapsis range	12.24e6	km
(B5)	Semi-major axis	18.44e6	km
(B6)	Apoapsis range	24.64e6	km
(B7)	Semi-major axis	306	R_Saturn
(B8)	Semi-major axis	0.123	au
(B9)	Semi-major axis	0.28	R_Hill
(B10)	Orbit eccentricity	0.34	
(B11)	Orbit inclination	151.5	°
(B12)	Inclination supplemental angle	28.5	°
(B13)	Orbital period	932	d
(B14)	Orbital period	2	6	2.75	y:m:w
(B15)	Mean orbit velocity	1.43	km/s

(C)	Physical parameters
(C1)	Mean size ~	8	-1.25	+2.25	km
(C2)	Mean radius ~	3.8	km
(C3)	Equatorial circumference ~	25	km
(C4)	Minimum equatorial axes ratio	1.27
(C5)	Axes radii (a x b x c) ~	unknown
(C5)	
(C6)	Mass ~	1e14	kg
(C7)	Mean density (?)	0.5	g/cm^3
(C8)	Surface escape velocity ~	5	km/h
(C9)	Rotation period	12.76	h
(C9)	Rotation period error	0.03	h
(C9)	Spin rate	1.88	d^(-1)
(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 ~	14.3	mag
(C15)	Apparent visual magnitude from Earth	23.5	mag
(C16)	Best apparent magnitude for Cassini	14.4	mag
(C17)	Spectral slope	
(C17)	B-R color index ~	1.23	
(C18)	Albedo (?)	0.06	
(C19)	Hill sphere radius ~	500	km
(C20)	Hill sphere radius ~	130	r_Hyr