ISON comet has lost individual fragments

November 21, 2013
The comet is centre stage: this image shows the gaseous environment of comet ISON with two wing-like structures which look like an elongated U (arrow). The nucleus is shown as a bright spot in the centre for orientation. Credit: Wendelstein Observatory / MPS

One or more chunks could have split off from the nucleus of comet ISON in recent days. Two wing-like structures in the gaseous environment of the comet, which have been photographed by a team of scientists from the Max Planck Institute for Solar System Research and the Wendelstein Observatory of the Ludwig Maximilian Universität Munich, seem to indicate this; the structures appear on images which were taken at the end of last week. This detachment of individual pieces of debris could possible explain the comet's recent increase in brightness.

Comet ISON has disappointed many amateur astronomers on its journey towards the Sun. The brightness of the comet, which will pass by the Sun's surface on 28 November at a relatively close distance of just over a million kilometres, did not increase as much as initially hoped. At the end of last week, the luminosity of ISON rose dramatically with several observers reporting a considerable increase in brightness.

A possible indication for the cause of the flare up is now provided by images of the comet which were taken and recently evaluated by scientists at the Wendelstein Observatory and the Max Planck Institute for Solar System Research. On 14 and 16 November they pointed their telescope towards the comet.

The analyses show two conspicuous structures in the comet's atmosphere which extend from the nucleus like wings. While these "wings" were still quite weak on 14 November, they clearly dominate the images taken two days later. "Such structures typically occur after individual fragments have split off from the nucleus of a comet," says Hermann Böhnhardt from the Max Planck Institute for Solar System Research.

Like the of the comet, its fragments also eject gas and dust into space. Where the emissions of the comet and the smaller chunks meet, a type of separating layer is generated, and this often has a wing-like character. Whether the increase in brightness seen in recent days was also caused by the fragments splitting off "cannot be said with certainty," says Böhnhardt. This relationship has been proven for other comets, however.

The wing-like structures on the images cannot be recognised with the naked eye, numerical methods are needed to make them appear in processed images. To this end the researchers scan the gaseous environment of the comet on the computer for changes in brightness. The uniformly bright background of the comet's atmosphere is subtracted and can thus no longer eclipse the weak structures. "Our computations indicate that either only a single chunk split off or that only very few pieces of debris were released," says Böhnhardt.

It is still unclear how the comet will behave in the coming weeks as it journeys around the Sun. "However, past experience has shown that comets which have lost fragments once have a tendency to do so again," says the researcher.

Explore further: Comet ISON unfolds its wings

Related Stories

Comet ISON unfolds its wings

November 19, 2013

( —One or more fragments may have detached from comet ISON in the past days, as two wing-shaped features in the comet's atmosphere suggest. Scientists from the Max Planck Institute for Solar System Research (MPS) ...

Incoming comet ISON appears intact to Hubble

October 17, 2013

( —A new image of the sunward plunging Comet ISON suggests that the comet is intact despite some predictions that the fragile icy nucleus might disintegrate as the Sun warms it. The comet will pass closest to the ...

Comet C/ISON details emerge as it races toward the Sun

October 11, 2013

Scientists are unraveling more information on Comet C/2012 S1 (ISON) as it continues on its journey toward the Sun. Comet C/ISON will skim 730,000 miles above the Sun's surface on Nov. 28 and has the potential to be readily ...

Fossil from the depths of the solar system

November 11, 2013

( —ISON is approaching the Sun. An international observation campaign which involves ground-based telescopes, space probes and space telescopes has been running for some time and is already providing initial findings. ...

NRL-developed telescopes await the approaching comet ISON

November 14, 2013

When Comet C/2012 S1 (ISON), a so-called Sungrazing comet, sweeps by the Sun on November 28, 2013, telescopes developed by the U.S. Naval Research Laboratory (NRL) will be lined up for a spectacular front row view.

MicroObservatory catches comet ISON

November 18, 2013

Hopes are high for Comet ISON, which has the potential to become the most spectacular comet seen in years. ISON is speeding through the inner solar system at about 120,000 miles per hour, on its way to a close approach to ...

Recommended for you

Solar minimum surprisingly constant

November 17, 2017

Using more than a half-century of observations, Japanese astronomers have discovered that the microwaves coming from the sun at the minimums of the past five solar cycles have been the same each time, despite large differences ...

Lava or not, exoplanet 55 Cancri e likely to have atmosphere

November 16, 2017

Twice as big as Earth, the super-Earth 55 Cancri e was thought to have lava flows on its surface. The planet is so close to its star, the same side of the planet always faces the star, such that the planet has permanent day ...

SpaceX poised to launch secretive Zuma mission

November 16, 2017

SpaceX is poised to launch on Thursday a secretive payload known as Zuma for the US government, though the nature of the mission and the agency behind it remain a mystery.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.