ESO Very Large Telescopes study comet after impact

July 05, 2005

Through the night of 4 July 2005, all European Southern Observatory (ESO) telescopes observed the effects of the impact on Comet 9P/Tempel 1. At sunset in Chile, the seven telescopes of the La Silla Paranal Observatory went into action.

The FORS2 multi-mode instrument on Antu, one of the 8.2-metre Unit Telescopes of the Very Large Telescope (VLT) array, took stunning images, showing that the morphology of the comet had dramatically changed: a new bright fan-like structure was now visible. The impact occurred at 07:52 CEST on 4 July. At that time, the comet had already set below the horizon in Chile, so ESO VLTs could only start observations several hours later, at 21:20 CEST. A pre-impact image is shown here for comparison.

The first ESO observations were actually done in the infrared by the TMMI2 instrument on the 3.6-metre telescope at La Silla, at 21:20 CEST (still daylight in Chile). These observations showed the comet to be two to three times brighter in the infrared than the day before the impact. The coma is also much more extended than it was before the impact.

The fan lies in the southern part of the image and is rather bright and well defined. This feature is an addition to those that were already visible during the previous days that seems to still be underlying the new one. Behind this fan, the old coma from yesterday is still present.

The new structure is about 15 000 kilometres in length, indicating that the matter has been ejected with a speed of about 700 to 1000 kilometres per hour.

Further observations during the week will study the evolution of this fan, revealing if the probe has activated a new region of the surface and how long that region remains active.

The fan is visible through the reflection of sunlight on dust grains. The fact that the big plume is not uniform in colour probably indicates that dust particles of different sizes are travelling at different speeds.

Later at La Silla, the SOFI instrument on the NTT telescope imaged the comet in the near-infrared.

An image in the J-band also shows the dust shell from the impact in the south-western quadrant of the coma.

The very inner coma (indicated by the white box) shows ongoing enhanced activity compared to the pre-impact level.

The astronomers at the La Silla Paranal Observatory will continue to observe Comet 9P/Tempel 1 for another four days in order to monitor precisely its longer-term behaviour.
-end-
For more information:

Claus Madsen, ESO Public Affairs Department Gerhard Schwehm, ESO VLT impact observations co-investigator
ESA-ESTEC (The Netherlands)
E-mail: gerhard.schwehm@esa.int

Rita Schulz, ESO VLT impact observations co-investigator
ESA-ESTEC (The Netherlands)
Email: rita.schulz@esa.int

The ESO article is available at: http://deepimpact.eso.org/obseso8.html

European Space Agency

Related Comet Articles from Brightsurf:

Comet Chury's ultraviolet aurora
On Earth, auroras, also called northern lights, have always fascinated people.

Hubble snaps close-up of comet NEOWISE
The NASA/ESA Hubble Space Telescope has captured the closest images yet of the sky's latest visitor to make the headlines, comet C/2020 F3 NEOWISE, after it passed by the Sun.

Hubble snaps close-up of celebrity comet NEOWISE
The Hubble Space Telescope has snapped the closest images yet of the sky's latest visitor to make headlines, comet NEOWISE, after it passed by the Sun.

New comet discovered by ESA and NASA solar observatory
In late May and early June, Earthlings may be able to glimpse Comet SWAN.

Hubble captures breakup of comet ATLAS
The NASA/ESA Hubble Space Telescope has provided astronomers with the sharpest view yet of the breakup of Comet C/2019 Y4 (ATLAS).

The salt of the comet
Under the leadership of astrophysicist Kathrin Altwegg, Bernese researchers have found an explanation for why very little nitrogen could previously be accounted for in the nebulous covering of comets: the building block for life predominantly occurs in the form of ammonium salts, the occurrence of which could not previously be measured.

New NASA image provides more details about first observed interstellar comet
A new image from NASA's Hubble Space Telescope provides important new details about the first interstellar comet astronomers have seen in our solar system.

Interstellar comet 2I -- Borisov swings past sun
Comet 2I/Borisov is a mysterious visitor from the depths of space -- the first identified comet to arrive here from another star.

Hubble observes 1st confirmed interstellar comet
Hubble has given astronomers their best look yet at an interstellar visitor -- comet 2I/Borisov -- whose speed and trajectory indicate it has come from beyond our solar system.

Interstellar Comet with a Familiar Look
A new comet discovered by amateur astronomer Gennady Borisov is an outcast from another star system, yet its properties determined so far are surprisingly familiar -- a new study led by JU researchers shows.

Read More: Comet News and Comet Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.