Holmes coma detail - October 30th

Hi all,

Here's another shot of the inner coma structures taken on the night of
the 30th October 2007. Note the interesting features close to the
pseudo-nucleus.

http://www.digitalsky.org.uk/comets/..._luminance.jpg

--
Pete Lawrence
http://www.digitalsky.org.uk

Top Notch as always!

great stuff Pete, no wonder so many people love your pictures

All the best

Andy

--
StarDome - Astronomy - Astronautics - Planetarium
Mr Andrew R Green B.Sc(Hons) FRAS.
Fellow Royal Astronomical Society
Director & Resident Astronomer StarDome,
Director Anglo-Australian Astronomy Education Partnership

Web Sites:
www.stardomeplanetarium.co.uk
www.stardome-planetarium.com




"Pete Lawrence" wrote in message
...
Hi all,

Here's another shot of the inner coma structures taken on the night of
the 30th October 2007. Note the interesting features close to the
pseudo-nucleus.

http://www.digitalsky.org.uk/comets/..._luminance.jpg

--
Pete Lawrence
http://www.digitalsky.org.uk

Being between the orbits of Mars and Jupiter and heading away, it's freaky
that Holmes is that volatile. The
solar flux at that distance is such that you have to wonder about this
unique comet.


"Pete Lawrence" wrote in message
...
Hi all,

Here's another shot of the inner coma structures taken on the night of
the 30th October 2007. Note the interesting features close to the
pseudo-nucleus.

http://www.digitalsky.org.uk/comets/..._luminance.jpg

--
Pete Lawrence
http://www.digitalsky.org.uk

On Thu, 01 Nov 2007 17:57:24 GMT, "ThomA" wrote:

Being between the orbits of Mars and Jupiter and heading away, it's freaky
that Holmes is that volatile. The
solar flux at that distance is such that you have to wonder about this
unique comet.

It is interesting, but actually a body at 2 AU from the Sun (the
perihelion distance of this comet) can experience significant heating.
Depending on its emissivity (which is unknown), temperatures can easily
get much higher than the boiling point for many compounds known to exist
in comets (some of which show up in spectra for this one). Assuming a
dark crust- probably common in comets- and a porous makeup- probably
common as well- it would take months for the heat to soak meters down
into the nucleus and encounter older, more volatile material.

At its current distance from the Sun of 2.5 AU, it is still perfectly
capable of absorbing enough energy to vaporize many common compounds if
they were suddenly exposed at the surface by a shift of material (comet
quake) or a low energy collision with co-orbital material.

Nobody knows for sure what precipitated this release of material but any
of the above are reasonable possibilities. The precipitating event is
apparently unusual, but the large release of volatiles isn't that odd.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

Chris L Peterson wrote:
[snip]

temperatures can
easily get much higher than the boiling point for many compounds
known to exist in comets (some of which show up in spectra for this
one).

Chris,

do you or anyone else have spectral data on Holmes?

Such as what kind of spectrum does it have and what are the most prominent
elements that show on its spectrum?

Thanks,

[snip]

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
--
I.N. Galidakis

On Thu, 1 Nov 2007 21:40:58 +0200, "I.N. Galidakis"
wrote:

do you or anyone else have spectral data on Holmes?

Check out John Menke's report at
http://menkescientific.com/Comet17P-Holmes.pdf


Such as what kind of spectrum does it have and what are the most prominent
elements that show on its spectrum?

CN, C2, NH2.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

Yes. The flux decreases 4 X's at double the distance. So some 200
watts/m** would
be rather warm.



At its current distance from the Sun of 2.5 AU, it is still perfectly
capable of absorbing enough energy to vaporize many common compounds if
they were suddenly exposed at the surface by a shift of material (comet
quake) or a low energy collision with co-orbital material.

Chris L Peterson wrote:
On Thu, 1 Nov 2007 21:40:58 +0200, "I.N. Galidakis"
wrote:

do you or anyone else have spectral data on Holmes?

Check out John Menke's report at
http://menkescientific.com/Comet17P-Holmes.pdf

Many thanks!

Such as what kind of spectrum does it have and what are the most
prominent elements that show on its spectrum?

CN, C2, NH2.
[snip]

What's C2?

Thanks again,

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
--
I.N. Galidakis

"I.N. Galidakis" wrote:

Chris L Peterson wrote:
[snip]

temperatures can
easily get much higher than the boiling point for many compounds
known to exist in comets (some of which show up in spectra for this
one).

Chris,

do you or anyone else have spectral data on Holmes?

Such as what kind of spectrum does it have and what are the most prominent
elements that show on its spectrum?


a number of good ones exist. Google /17P Holmes spectrum/ or /spectrum of...?

Major emissions are C2 around the Mg triplet at 5129,65, and 85.
C2+NH2 spikes in the CN A region at 5693, 5703, 5732.
Na at 5976 and 5995. The object is proving a challenge for
amateurs. There are some very nbice spectra on the web.
To your last CII is carbon.

.. ..







Thanks,

[snip]

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
--
I.N. Galidakis

"I.N. Galidakis" wrote in message
news:1193963847.410582@athprx03...
Chris L Peterson wrote:
On Thu, 1 Nov 2007 21:40:58 +0200, "I.N. Galidakis"
wrote:

do you or anyone else have spectral data on Holmes?

Check out John Menke's report at
http://menkescientific.com/Comet17P-Holmes.pdf

Many thanks!

Such as what kind of spectrum does it have and what are the most
prominent elements that show on its spectrum?

CN, C2, NH2.
[snip]

What's C2?


Diatomic carbon molecule. I believe (without checking references) this one
is responsible for Swan bands in the rare red giant carbon stars also.

NOT ionized carbon atom as found in B stars.

Thanks again,

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
--
I.N. Galidakis



--
Mike Dworetsky

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