[meteorite-list] EPOXI images of Comet Hartley 2

[Meteorites USA]

My mistake on the method of propulsion... Thanks for clearing that up 
for me Chris.. ;)

On 11/4/2010 10:03 AM, Chris Peterson wrote:
> Eric-
>
> The Yarkovsky effect does not work by vaporizing material. It is 
> related to the momentum of photons.
>
> In the case of outgassing, the momentum is very low compared with the 
> momentum of the nucleus, so the effect on the orbit is small as well. 
> The Yarkovsky effect is also quite small on a body the size of 
> Hartley. I think Yarkovsky dominates because it is a continuous 
> process over the entire orbit, whereas outgassing only occurs during 
> the time the nucleus is near the Sun. But in reality, both effects, as 
> well as others (like gravitational perturbation) produce an orbit that 
> can't be accurately predicted too far into the future. It is important 
> to regularly recalculate orbital elements for bodies like this if very 
> precise position information is required. I noticed during the flyby 
> this morning that there seemed to be a miscalculated close passage 
> time, which was corrected by a few minutes when the comet's orbit was 
> recalculated.
>
> Chris
>
> *****************************************
> Chris L Peterson
> Cloudbait Observatory
> http://www.cloudbait.com
>
>
> ----- Original Message ----- From: "Meteorites USA" 
> <eric at meteoritesusa.com>
> To: <meteorite-list at meteoritecentral.com>
> Sent: Thursday, November 04, 2010 10:35 AM
> Subject: Re: [meteorite-list] EPOXI images of Comet Hartley 2
>
>
>> Hi Gary, Your explanation of the outgassing of comets and Count 
>> Deiro's question, made me think of one of the proposed ways of 
>> deflecting asteroids which uses the Yarkovsky effect to focus the 
>> suns energy on the outer surface of the asteroid thereby vaporizing 
>> material and causing a propulsive force to nudge the asteroid into a 
>> new orbit.
>>
>> So, if the Yarkovsky effect will work on asteroids, what's the 
>> difference between that, and Comet Hartley 2's outgassing on the 
>> orbit of the body? Is the force from the outgassing that much less 
>> than what the Yarkovsky effect could produce?
>>
>> Regards,
>> Eric
>
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