Acronym	sisro
Name	star stellarotunda, half of great icosidodecahedron
VRML	⭳
Circumradius	(sqrt(5)-1)/2 = 0.618034
Vertex figure	[(3,5/2)2], [3,5/2,10/3]
Dihedral angles	between {3} and {5/2}:   arccos(-sqrt[(5-2 sqrt(5))/15]) = 100.812317° between {5/2} and {10/3}:   arccos(1/sqrt(5)) = 63.434949° between {3} and {10/3}:   arccos(sqrt[(5+2 sqrt(5))/15]) = 37.377368°
Face vector	20, 35, 17
Confer	related Johnson solids: pero   uniform relative: gid
External links

This polyhedron is an edge-faceting of the great icosidodecahedron (gid).

As abstract polytope sisro is isomorphic to pero, thereby replacing pentagrams by pentagons and the retrograde decagram by a prograde decagon.

Incidence matrix according to Dynkin symbol

xox5/3o(-v)x&#(x,-x)t - height(1,2) = sqrt[(5+sqrt(5))/10] = 0.850651
                        height(2,3) = sqrt[(5-sqrt(5))/10] = 0.525731
(star || pseudo (-v)-star || deg)

o..5/3o  . .          | 5 *  * | 2  2  0 0 0 | 1 2 1 0 0
.o.5/3.  o .          | * 5  * | 0  2  2 0 0 | 0 1 2 1 0
..o5/3.  . o          | * * 10 | 0  0  1 1 1 | 0 0 1 1 1
----------------------+--------+-------------+----------
x..   .  . .          | 2 0  0 | 5  *  * * * | 1 1 0 0 0
oo.5/3o  o .&#x       | 1 1  0 | * 10  * * * | 0 1 1 0 0
.oo5/3.  o o&#(-x)    | 0 1  1 | *  * 10 * * | 0 0 1 1 0
..x   .  . .          | 0 0  2 | *  *  * 5 * | 0 0 0 1 1
...   .  . x          | 0 0  2 | *  *  * * 5 | 0 0 1 0 1
----------------------+--------+-------------+----------
x..5/3o  . .          | 5 0  0 | 5  0  0 0 0 | 1 * * * *  {5/2}
xo.   .  . .&#x       | 2 1  0 | 1  2  0 0 0 | * 5 * * *
...   o(-v)x&#(x,-x)t | 1 2  2 | 0  2  2 0 1 | * * 5 * *  {5/2}
.ox   .  . .&#(-x)    | 0 1  2 | 0  0  2 1 0 | * * * 5 *
..x5/3.  . x          | 0 0 10 | 0  0  0 5 5 | * * * * 1  {10/3}