# Comets
"Halley:1P Halley" "Sol" 
{ 
	Class "comet" 
	Mesh "halley.cmod"
	Texture "asteroid.jpg" 
	Radius 7.6 # maximum semi-axis
	MeshCenter [ -0.338 1.303 0.230 ]

	EllipticalOrbit 
	{ 
	Epoch        2449400.5      #1994 Feb 17 00:00UT
	Period            75.31589 
	SemiMajorAxis     17.834144 
	Eccentricity       0.967143 
	Inclination      162.262690 
	AscendingNode     58.420081 
	ArgOfPericenter  111.332485 
	MeanAnomaly       38.384264 
	} 

	# chaotic rotation, imperfectly defined: 
	# this version from "The New Solar System", 4th Edition; Eds.
	# JK Beatty, CC Petersen, A Chaikin 
	PrecessingRotation
	{
	Period             170          # 7.1 day axial rotation period 
	Inclination         66    
	PrecessionPeriod     0.010      # 3.7 day precession period 
	}

	Albedo 0.04 
} 

"Borrelly:19P Borrelly" "Sol" 
{ 
	Class "comet" 
	Mesh "borrelly.cms" 
	Texture "asteroid.jpg" 
	Radius 2.2 

	InfoURL "http://www.solarviews.com/eng/borrelly.htm"

	EllipticalOrbit 
	{ 
	Epoch        2452174.5      # 2001 Sep 22 00:00UT
	Period             6.86302 
	SemiMajorAxis      3.611363 
	Eccentricity       0.623908 
	Inclination       30.324612 
	AscendingNode     75.424869 
	ArgOfPericenter  353.375385 
	MeanAnomaly      358.956091 
	} 

	UniformRotation
	{
	Period         25 
	Inclination    90 
	AscendingNode 315 
	}

	Albedo 0.04 
} 

"Ikeya-Zhang:153P Ikeya-Zhang" "Sol" 
{ 
	Class "comet" 
	Texture "asteroid.jpg" 
	Mesh "roughsphere.cms" 

	EllipticalOrbit 
	{ 
	Epoch        2452352.47847  # 2002 Mar 18 23:29UT
	Period           367.181906 
	SemiMajorAxis     51.276792 
	Eccentricity       0.990111 
	Inclination       28.1206 
	AscendingNode     93.3718 
	ArgOfPericenter   34.6666 
	MeanAnomaly        0 
	} 

	# These are all made up (copied from Halley)
	Radius           7.5 

	UniformRotation
	{
	Period 170 
	}

	Albedo 0.04 
} 

"Hale-Bopp:C1995 O1 Hale-Bopp" "Sol"
{
	Class "comet"
	Mesh "asteroid.cms"
	Texture "asteroid.jpg"
	Radius 13

	EllipticalOrbit
	{
	Period          2523.4
	PericenterDistance 0.914142
	Eccentricity      0.995068
	Inclination      89.4300
	AscendingNode   282.4707
	ArgOfPericenter 130.5887
        MeanAnomaly       -0.007
	Epoch       2450520.5
	}

	# Estimate of rotation period from here: http://www.usafa.af.mil/dfp/research/astro/papers/icqpaper.htm
	RotationPeriod  11.47
	Albedo            0.1
}
