Hubble Peers into Comet Holmes

The first of my 'Hubble Highlights' series.

15-November-2007 The NASA/ESA Hubble Space Telescope has probed the bright core of Comet 17P/Holmes which, to the delight of sky watchers, mysteriously brightened by nearly a million-fold in a 24-hour period beginning October 23, 2007. Astronomers have used Hubbles powerful resolution to study Comet Holmes core for clues about how the comet brightened. The orbiting observatorys Wide Field Planetary Camera 2 (WFPC2) monitored the comet for several days, snapping images on 29 Oct., 31 Oct. and 4 Nov. Hubbles crisp eye can see details as small as 54 kilometres across, providing the sharpest view yet of the source of the spectacular brightening. The Hubble image at right, taken on 4 Nov., shows the heart of the comet. The central portion of the image has been specially processed to highlight variations in the dust distribution near the nucleus. About twice as much dust lies along the east-west direction (the horizontal direction) as along the north-south direction (the vertical direction), giving the comet a bow tie appearance. The composite colour image at left, taken Nov. 1 by the amateur astronomer Alan Dyer shows the complex structure of the entire coma, consisting of concentric shells of dust and a faint tail emanating from the comets right side. The nucleus — the small solid body that is the source of the comets activity — is still swaddled in bright dust, even 12 days after the spectacular outburst. Most of what Hubble sees is sunlight scattered from microscopic particles, explained Hal Weaver of The Johns Hopkins University Applied Physics Laboratory of Laurel, Maryland in the USA, who led the Hubble investigation. But we may finally be starting to detect the emergence of the nucleus itself in this final Hubble image. Hubble first observed Comet 17P/Holmes on June 15, 1999, when there was virtually no dusty shroud around the nucleus. Although Hubble cannot resolve the nucleus, astronomers inferred its size by measuring its brightness. Astronomers deduced that the nucleuss diameter was approximately 3.4 kilometres, about the distance between the Arc de Triomphe and the Louvre glass pyramid in Paris. They hope to use the new Hubble images to determine the size of the comets nucleus to see how much of it was blasted away during the outburst. Hubbles two earlier snapshots of Comet Holmes also showed some interesting features. On 29 Oct. the telescope spied three spurs of dust emanating from the nucleus while the Hubble images taken on 31 Oct. revealed an outburst of dust just west of the nucleus.
The Hubble images however do not show any large fragments near the nucleus of Comet
2
Holmes, unlike the case of Comet 73P/Schwassmann-Wachmann 3 (SW3). In the spring of 2006 Hubble observations revealed a multitude of mini-comets ejected by SW3 after the comet increased dramatically in brightness. Ground-based images of Comet Holmes show a large, spherically symmetrical cloud of dust that is offset from the nucleus, suggesting that a large fragment broke off and subsequently disintegrated into tiny dust particles after moving away from the main nucleus. Unfortunately, the huge amount of dust near the comets nucleus and the relatively large distance from Earth (240 million kilometres, or 1.6 astronomical units for Holmes versus 15 million kilometres, 0.1 astronomical units for SW3), conspire to make detecting fragments near Holmes nearly impossible right now, unless the fragments are nearly as large as the nucleus itself.

[MegzeeR]

Thank you for posting these beautiful pictures and not adding all the gloom and doom that I get when trying to find out about comets.  Love the music too.

[oranjedan]

I remember this event... I called my freind cuz I wanted to use his telescope (more powerful). It looked like a fried egg. Something really weird happened there...I still have the picture we took.

[Ashaneen]

Yep. Hopi (blue) star.
Expecting the red star soon. Hmm...

[jochem]

Can you please tell me the name of the song that starts at 39s. It;s so beautiful..

[GEAUXFRUGAL]

Why land on a comet why not put a telescope on an asteroid I want a comet but they are so jazzed up nearer the sun they would toss and tumble until they reached a <volatile trajectory. I guess equipment could be secured, programmed to send back images as it made it's 75 205 ?? Year trek talk about your ultimate time capsule. My guess is you couldn't expect any true power from solar, also the radio signal would be near impossible to receive outside of 9 billion miles. Too bad it couldn't release small drones into directions where we could glean information. Could blast off at the proper moment and do a shot from the exiting projectiles and return to the Solar system like a basketball shot, returning at angles we couldn't get . Just see what's out there ? In fact they could probably put them on multiple asteroids the have multiple paths giving us visual in areas that would be too difficult or expensive to take those paths. Tossing space drones along the way.