Overly long orbit problem

[Darkmiss]

Hello Grant or anyone else who might know my problem.

I was looking at my Orbits the other day and i noticed a Comet that had a very very long orbit. and an almost straight line.
It just looked out of place, and wrong.

here is the code i have for the comet
Can anyone see if there is a mistake in there somewhere ?

Code: Select all

"C/1996 B2 Hyakutake" "Sol"
{
   Class "comet"
   Mesh  "asteroid.cms"
   Texture "comet.png"
   Radius 1.3

   EllipticalOrbit
    {
    Period        247594.0
    PericenterDistance 2.337779413391891E-01
    Eccentricity       9.999407170553701E-01
    Inclination        1.246225591888924E+02
    AscendingNode      1.887609399998953E+02
    ArgOfPericenter    1.307272865438558E+02
    MeanAnomaly        9.432006669030560E-03
    Epoch        2452575.50
    }

    RotationPeriod 6.23
}

[selden]

Four 9s of eccentricity and a very long period are the reasons it looks like a line. They're typical of many "new" comets on their first trip in from the Oort cloud. Shorter periods and more circular orbits are the results of gravitational interactions with various planets.

If you use code instead of quote, it'll preserve formatting.

Does this help?

Written later:
FWIW, you seem to have edited one of the Hyakutake .ssc files from my Web site, taking out the comments. If you'd left them in, they probably would have answered your questions about the values. This set of orbital elements came from Horizons. The period and eccentricity both are quite a bit larger than the values measured by many observers.

[Darkmiss]

Ah thats better, Looks a lot better when using code
Thanks Selden, Now i know what that does.

So What i need to know is the code for this Comet Correct.
Because it just seemed so odd.

I turned on the Orbits for comets only,
And they all looked great, Except for Hyakutake.
It just had such a long orbit, with very little width to it.

[selden]

Comet Hyakutake hasn't been observed since 1996.

The orbital elements you're showing are for October, 2002, as predicted by Horizons. Evidently the original observations weren't accurate enough to produce reliable predictions that far in the future. Horizons currently refuses to provide orbital elements for the comet past the end of December, 1996.


(I'll post them later: I've gotta go to a meeting now.)

[granthutchison]

It's an absolutely normal orbit for a long-period comet - the aphelion is only about an eighth of a light-year, which means that its orbit has probably been modified on its recent (or a previous) passage through the solar system, since the vast bulk of the Oort cloud (the source of long-period comets) lies well beyond that distance.
Try following Hyakutake in accelerated time as it climbs out of the solar system - keep orbits switched on and look back towards the Sun. It gives you an idea of how remote the Oort really is.

Grant

[selden]

Here are Horizons' orbital parameters for Comet Hyakutake as of 1-Dec-1996. Note that the period and eccentricity are less than are specified in the other set of parameters.

Code: Select all

# Comet Hyakutake
# radius and orbit values are as described on
# http://www.psrd.hawaii.edu/Feb97/Bright.html
# rotation period as described on
# http://www.lowell.edu/Research/Projects/hyakutake_research/hyaresearch.html
#
# ephemeris values obtained from Horizons 10jul03
# ephemeris values are no longer available for dates after 30 Dec 1996.
#
"C/1996 B2 Hyakutake" "Sol"
{
Class "comet"
Texture "asteroid.jpg"
Mesh "asteroid.cms"
Radius 1.3
RotationPeriod 6.23
#
#2450418.500000000 = A.D. 1996-Dec-01 00:00:00.0000 (CT)
#EC= 9.998972424367671E-01 QR= 2.302006430980918E-01 IN= 1.249226804321613E+02
#OM= 1.880592987945111E+02 W = 1.301731366226371E+02 Tp= 2.450204891150602E+06
#N = 9.295333380324437E-06 MA= 1.985565468156961E-03 TA= 1.511809795921010E+02
#A = 2.240230654131714E+03 AD= 4.480231107620330E+03 PR= 3.872911118626655E+07
#
EllipticalOrbit
 {
 Period              106032.524953615
 PericenterDistance       2.302006430980918E-01
 Eccentricity             9.998972424367671E-01
 Inclination              1.249226804321613E+02
 AscendingNode            1.880592987945111E+02
 ArgOfPericenter          1.301731366226371E+02
 MeanAnomaly              1.985565468156961E-03
 Epoch              2450418.5
 }

}


[Darkmiss]

Ah thats great, thanks guys.
I just wasn't sure if what i was seeing was right.

But now I have had a couple of experts confirm its okay,
I feel better.

thanks again.