T_jup

What is the Jupiter Tisserand invariant? Jupiter
I know and Tisserand I know, but not T_jup.

"Axel Harvey" wrote in message
oups.com...
What is the Jupiter Tisserand invariant? Jupiter
I know and Tisserand I know, but not T_jup.

Good question. Can you supply more context?
T's usually imply orbital period, but I don't
see how it would apply to Tisserand's Criterion.

Dear Greg Neill:

"Greg Neill" wrote in message
m...
"Axel Harvey" wrote in message
oups.com...
What is the Jupiter Tisserand invariant? Jupiter
I know and Tisserand I know, but not T_jup.

Good question. Can you supply more context?
T's usually imply orbital period, but I don't
see how it would apply to Tisserand's Criterion.

May be this Word document?
http://www.academic2.american.edu/~s...Case_Study.doc

David A. Smith

"Greg Neill" wrote in message
m...
"Axel Harvey" wrote in message
oups.com...
What is the Jupiter Tisserand invariant? Jupiter
I know and Tisserand I know, but not T_jup.

Good question. Can you supply more context?
T's usually imply orbital period, but I don't
see how it would apply to Tisserand's Criterion.

Okay, I'm following up my own post...

It would appear that T_jup refers to the value
of the Tisserand Invariant that distinguishes
between the various families of comets.

For example, T_jup 2 places the comet in the Halley
family. T_jup 2 places it in the Jupiter family.

See:

http://www.physics.ucf.edu/~yfernandez/cometlist.html

Thanks to responders.

Okay, one reference tells me that T_jup stands for the Jupiter
Tisserand invariant, which I know already, and the other that
the value of T_jup is used to place a comet in one group or
another.

Now, can someone tell us how T_jup is defined? What is its
physical significance?

Greg Neill wrote:

[ ... ]
It would appear that T_jup refers to the value
of the Tisserand Invariant that distinguishes
between the various families of comets.

For example, T_jup 2 places the comet in the Halley
family. T_jup 2 places it in the Jupiter family.

See:

http://www.physics.ucf.edu/~yfernandez/cometlist.html

"Axel Harvey" wrote in message
ps.com...
Thanks to responders.

Okay, one reference tells me that T_jup stands for the Jupiter
Tisserand invariant, which I know already, and the other that
the value of T_jup is used to place a comet in one group or
another.

Now, can someone tell us how T_jup is defined? What is its
physical significance?

I suspect that T_jup = 2 is an arbitrary classification
criterion (I'll keep looking though).

This page gives some additional information about how to
calculate the values:

http://farside.ph.utexas.edu/teachin...s/node122.html

Note that the unit system being used is one in which
the semimajor axis of Jupiter's orbit (essentially
Jupiter's orbital radius) is the distance unit.

Thanks Greg!

Greg Neill wrote:
"Axel Harvey" had written:

Now, can someone tell us how T_jup is defined? What is its
physical significance?

I suspect that T_jup = 2 is an arbitrary classification
criterion (I'll keep looking though).

This page gives some additional information about how to
calculate the values:

http://farside.ph.utexas.edu/teachin...s/node122.html

The reference above tells me exactly what I wanted.
Essentially, T_jup is a formula incorporating the
eccentricity of a small body's orbit, its semi-major
axis, and the angle between its plane and that of a
much heavier orbiting body (in this case Jupiter) such
that T_jup remains constant. Thus the value can be
used, among other ways, to determine if a sighted
comet is the same as one observed earlier or a new
comet. And yes, the criterion T_jup or 2 has
something arbitrary about it, but what I didn't know was
how they got all those specific T_jup values.

If I'm wrong I hope someone corrects me.