[meteorite-list] EPOXI images of Comet Hartley 2

From: Meteorites USA <eric_at_meteoritecentral.com>
Date: Thu, 04 Nov 2010 09:35:05 -0700
Message-ID: <4CD2E0B9.3000909_at_meteoritesusa.com>

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



On 11/4/2010 9:18 AM, Gary Fujihara wrote:
> Aloha Count,
>
> Comets like Hartley 2 are comprised of rock, dust, water ice and frozen gases like carbon monoxide, methane and ammonia. As the comet approaches the sun, volatile material vaporize and outgas from the nucleus from solar radiation.
>
> Although the outgassing of Comet Hartley 2 is quite active as can be seen in the spacecraft close approach images, and does impart a force (and a reactive force against the direction of the outgassing on the comet itself), it is negligible and does not alter the trajectory of the minor body to any appreciable degree due to the mass of the comet itself.
>
> gary
>
> On Nov 4, 2010, at 6:07 AM, Count Deiro wrote:
>
>
>> Gary and List,
>>
>> Thank you for the post, Big Kahuna. Anybody know if all that outgassing imparts any thrust to the comet... and if so would it affect its orbit?
>>
>> Count Deiro
>> IMCA 3536
>>
>>
>>
>>
>> -----Original Message-----
>>
>>> From: Gary Fujihara<fujmon at mac.com>
>>> Sent: Nov 4, 2010 8:49 AM
>>> To: MeteorList<meteorite-list at meteoritecentral.com>
>>> Subject: [meteorite-list] EPOXI images of Comet Hartley 2
>>>
>>> For those of you who missed the live webcast, EPOXI spacecraft flew by Comet Hartley 2 a few minutes ago and took some absolutely stunning pictures with its Medium Resolution Imager. Here is a composite of 3 of the 5 closest approach images:
>>>
>>> http://bigkahuna-meteorites.com/Images/CometHartley-04.jpg
>>>
>>> EPOXI mission webpage: http://epoxi.umd.edu/
>>>
>>> Gary Fujihara
>>> Big Kahuna Meteorites (IMCA#1693)
>>> 105 Puhili Place, Hilo, Hawai'i 96720
>>> http://bigkahuna-meteorites.com/
>>> http://shop.ebay.com/fujmon/m.html
>>> (808) 640-9161
>>>
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>>
> Gary Fujihara
> Big Kahuna Meteorites (IMCA#1693)
> 105 Puhili Place, Hilo, Hawai'i 96720
> http://bigkahuna-meteorites.com/
> http://shop.ebay.com/fujmon/m.html
> (808) 640-9161
>
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Received on Thu 04 Nov 2010 12:35:05 PM PDT