* Astronomy

Blobrana · L

RE: Comet 73P/Schwassmann-Wachmann 3

Blobrana · L

Comet 73P-C/Schwassmann-Wachmann 3

DateTT        R.A. (2000) Dec.       Delta     r      Elong.  Phase   mag   
2006 07 04    02 03.84   -11 30.0    0.432    1.021    78.3    77.3  10.3  
2006 07 09    02 10.26   -11 35.1    0.461    1.051    81.3    73.0  10.6 
2006 07 14    02 15.68   -11 41.0    0.487    1.084    84.5    69.0  11.0  
2006 07 19    02 20.07   -11 49.4    0.510    1.120    87.9    65.0  11.3 
2006 07 24    02 23.35   -12 01.3    0.531    1.159    91.6    61.2  11.6  
2006 07 29    02 25.45   -12 17.4    0.550    1.200    95.5    57.4  11.9

Blobrana · L

73P-B/Schwassmann-Wachmann 3

Date(TT)  R.A. (2000) Dec.   Delta     r    Elong.  mag   
June 10   1 23.26   -9 43.1   0.234   0.940    64    7.9   
June 17   1 39.10  -11  7.8   0.288   0.949    68    8.4

73P-C/Schwassmann-Wachmann 3

Date(TT)  R.A. (2000) Dec.   Delta     r    Elong.  mag   
June 10   1 17.85   -9 42.4   0.255   0.940    65    8.1   
June 17   1 34.95  -10 49.3   0.309   0.951    69    8.5

Blobrana · L

In the Northern Hemisphere, it locates extremely low in the morning skies.
After July, it will rise gradually higher, however, it will be fading rapidly.

Date(TT)  R.A. (2000) Decl.   Delta     r    Elong.  mag.  
June  3   0 55.01   -7 25.0   0.201   0.941    63    7.5   
June 10   1 17.85   -9 42.4   0.255   0.940    65    8.1

Blobrana · L

Comet 73P meteors

Blobrana · L

RE: Comet 73P/Schwassmann-Wachmann 3

Blobrana · L

ESA’s new camera follows disintegration of a comet.

The continuing disintegration of Comet 73P/Schwassmann-Wachmann 3 has allowed ESA scientists to see into the interior of the comet. Using a revolutionary camera attached to the ESA Optical Ground Station on Tenerife, they have followed the detailed twists and turns of various comet fragments.

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Credit: ESA

The superconducting camera, SCAM, is an ultra fast photon counting camera, developed by ESA. It is cooled to just 300 thousandths of a degree above absolute zero. This enables its sensitive electronic detectors, known as superconducting tunnel detectors, to register almost every single photon of light that falls into it. As such, it is the perfect instrument with which to detect fast and faint changes in the fragments of the comet.
SCAM was attached to the one-metre ESA Optical Ground Station telescope on 7 May 2006, when the disintegrating comet was observed . Every few microseconds, the camera reads out the number of photons that have touched it and their colour. Using the unprecedented accuracy of the camera, ESA scientists charted the evolution of the dust and gas envelopes associated with each fragment for two hours. Now they must analyse the results.

In particular they will be looking for differences in the size and shape of the fragments and also any colour differences between them that might indicate compositional differences. Other studies are made possible by SCAM’s unrivalled time resolution. Outbursts and activity from each fragment can be traced down to changes that occur on a timescale of one minute. In addition, as the dust and gas particles released from the fragments move with velocities between 0.5 and 1 kilometres per second, the observations will allow the interaction of the gas and dust flow to be studied for the two fragments closest to one another.

Comet 73P/Schwassmann-Wachmann 3 is one of the comets that was considered as a potential target for ESA’s Rosetta mission. In 1995 even before its initial splitting, it was abandoned in favour of comet 46P/Wirtanen. After the launch delay of 2003, ESA decided not to re-select 73P/Schwassmann-Wachmann 3 as the replacement Rosetta target, because of the comet’s volatile behaviour. In 2014, Rosetta will rendezvous and land on the Jupiter-family comet 67P/Churyumov-Gerasimenko.

-- Edited by Blobrana at 18:26, 2006-05-19

Blobrana · L

NASA scientists said that they have detected X-rays from Comet 73P/Schwassman-Wachmann 3, which is now passing Earth and rapidly disintegrating on what could be its final orbit around the Sun.

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Image credit: NASA/Swift/XRT/U.

Comet 73P/Schwassmann-Wachmann 3 is the brightest comet ever detected in the X-ray band. This NASA Swift image shows the comet in X-rays as it moves closer to the Earth on its orbit around the sun (at a safe distance millions of miles away). The white speck is the near the comet core; the yellow and bright red areas show the comet's halo and tail. Scientists hope to learn about the composition of the comet and of the solar wind, which interacts with the comet to make X-rays. This is a rare opportunity because certain key information about the comet and solar wind is seen only via spectral lines in X-ray energies. As the comet moves closer to the Earth and sun, other X-ray satellites will observe the comet in detail. Note that the X-rays are to the left of the nucleus (towards the sun) because they are produced by interactions with the solar wind.

Blobrana · L

The Subaru Telescope on Mauna Kea has captured an image of the comet Schwassmann-Wachmann 3 as its nucleus continues to crumble into more than fifty pieces. Subaru observed one of these icy chunks, called Fragment B, on May 3, 2006, using the telescope's wide-field camera Suprime-Cam as the comet passed within 16.5 million kilometres from Earth. (This is about 41 times the distance between Earth and the Moon.) The resulting visible-light image shows gas and dust forming the characteristic shape of a comet, with a halo-like coma and dust tail around Fragment B. Amazingly, it also reveals at least thirteen mini-comets that have recently broken off from the fragment. This is five more than were found in observations on April 23, 2006 by the European Southern Observatory's VLT (Very Large Telescope) in Chile.

Credit Subaru

A detailed analysis of the cometary fragments is yet to come. However astronomers have determined that the small pieces are only several tens of kilometres in diameter and are likely to disappear in a short time. Exactly how short is one of the questions astronomers are hoping to answer.

"The combination of information from many telescopes including large telescopes like Subaru and the VLT and smaller telescopes like the Ishigakijima Astronomical Observatory in Okinawa, Japan, will give us the insight into how comets fall apart and conversely how they hold together" - Tetsuharu Fuse, from Subaru Telescope.

Comets are often described as "dirty snowballs," loose clumps of dust and ice covered by a crust of dirt. As they approach the Sun, comets can warm up and fall apart. In 1995, astronomers saw this comet become a thousand times brighter, and found that its nucleus had broken into three pieces. This year, observations from around the world have confirmed that the nucleus has broken into more than 50 pieces.

Blobrana · L

Astronomers have recently been enjoying front-row seats to a spectacular cometary show. Comet 73P/Schwassmann-Wachmann 3 is in the act of splitting apart as it passes close to Earth. The break-up is providing a firsthand look at the death of a comet.

Eran Ofek of the California Institute of Technology and Bidushi Bhattacharya of Caltech's Spitzer Science Centre have been observing the comet's tragic tale with the Palomar Observatory's 200-inch Hale Telescope. Their view is helping them and other scientists learn the secrets of comets and why they break up.
The comet was discovered by Arnold Schwassmann and Arno Arthur Wachmann 76 years ago and it broke into four fragments just a decade ago. It has since further split into dozens, if not hundreds, of pieces.

"We've learned that Schwassmann-Wachmann 3 presents a very dynamic system, with many smaller fragments than previously thought" - Bidushi Bhattacharya.

In all, 16 new fragments were discovered as a part of the Palomar observations.
A sequence of images showing the piece of the comet known as fragment R has been assembled into a movie. The movie shows the comet in the foreground against distant stars and galaxies, which appear to streak across the images. Because the comet was moving at a different rate across the sky than the stellar background, the telescope was tracking the comet's motion and not that of the stars. Fragment R and many smaller fragments of the comet are visible as nearly stationary objects in the movie.

"Seeing the many fragments was both an amazing and sobering experience" - Eran Ofek.

The images used to produce the movie were taken over a period of about an hour and a half when the comet was approximately 17 million kilometres from Earth. Astronomically speaking the comet is making a close approach to Earth this month giving astronomers their front-row seat to the comet's break up. Closest approach for any fragment of the comet occurs on May 12, when a fragment will be just 5.5 million miles from Earth. This is more than 20 times the distance to the moon. There is no chance that the comet will hit Earth.

"It is very impressive that a telescope built more than 50 years ago continues to contribute to forefront astrophysics, often working in tandem with the latest space missions and biggest ground-based facilities" - Shri Kulkarni, MacArthur Professor of Astronomy and Planetary Science and director of the Caltech Optical Observatories.

The Palomar observations were coordinated with observations acquired through the Spitzer Space Telescope, which imaged the comet's fragments in the infrared. The infrared images, combined with the visible-light images obtained using the Hale Telescope, will give astronomers a more complete understanding of the comet's break up.

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