Subscribe to our free daily newsletters
. 24/7 Space News .




Subscribe to our free daily newsletters



IRON AND ICE
Spinning comet rapidly slows down during close approach to Earth
by Staff Writers
Flagstaff, AZ (SPX) Oct 19, 2017


Images of the comet 41P/Tuttle-Giacobini-Kresak obtained on March 19th, 2017 using the Discovery Channel Telescope. Most of the emission from the coma was artificially removed to show the structure of the jets. There is a difference of six hours between the two images and both jets are rotating clockwise. The faint jet on the left image increases in strength as sunlight hits the region, while the other jet nearly shuts off completely as its source on the nucleus moves into night. The comet rotation period was 24 hours and increased to 27 hours only ten days later. Credit: Schleicher/Lowell Observatory.

Astronomers at Lowell Observatory observed comet 41P/Tuttle-Giacobini- Kresak last spring and noticed that the speed of its rotation was quickly slowing down. A research team led by David Schleicher studied the comet while it was closer to the Earth than it has ever been since its discovery. The comet rotational period became twice as long, going from 24 to more than 48 hours within six weeks, a far greater change than ever observed before in a comet. If it continues to slow down, it might stop completely and then begin rotating in the opposite direction.

Comet 41P/Tuttle-Giacobini-Kresak is a short period comet that now completes an orbit around the Sun every 5.4 years. First discovered by H. Tuttle in 1858, it was lost for years until is was rediscovered by M. Giacobini in 1907. Lost again and rediscovered for a third time in 1951 by K. Kresak, now the comet holds the names of its three independent discoverers.

Astronomers had a hard time studying this comet in detail until early 2017 when it passed within 13 million miles (21 million kilometers) from Earth, the closest since its discovery. With a relatively inactive nucleus estimated to be less than one mile in size (about 1.4 km), this comet was finally sufficiently bright for an extensive observing campaign.

During eight weeks between March and May of this year, the comet remained at a distance of less than 18 million miles (30 million kilometers) from Earth. In comparison, the distance between the Sun and the Earth is 93 million miles. These conditions allowed astronomers to study it in great detail.

Remnants from the formation of the solar system, comets have changed very little during the past 4.5 billion years. As a comet gets closer to the Sun and the ice on its surface vaporizes, it develops gas and dust jets thousands of miles in length that ultimately create the coma or head, and the tail that distinguish comets from asteroids and other celestial bodies. One of the most common gases found in comets is the cyanogen radical, a molecule composed of one carbon atom and one nitrogen atom.

Schleicher and his collaborators used Lowell Observatory's Discovery Channel Telescope, together with the Hall telescope and the Robotic telescope located on Anderson Mesa near Flagstaff, Arizona. They found and measured the motion of two cyanogen jets coming from comet 41P/Tuttle-Giacobini-Kresak. From these jets, they determined that the rotation period changed from 24 hours in March to 48 hour in late April, slowing down to less than half the rotation speed by the end of the observing campaign in May.

"While we expected to observe cyanogen jets and be able to determine the rotation period, we did not anticipate detecting a change in the rotation period in such a short time interval. It turned out to be the largest change in the rotational period ever measured, more than a factor of ten greater than found in any other comet," said Schleicher, who led the project.

This result also implies that the comet has a very elongated shape, a low density, and that the jets are located near the very end of its body, providing the torque needed to produce the observed change in rotation.

"If future observations can accurately measure the dimensions of the nucleus, then the observed rotation period change would set limits on the comet's density and internal strength. Such detailed knowledge of a comet is usually only obtained by a dedicated spacecraft mission like the recently completed Rosetta mission to comet 67P/Churyumov-Gerasimenko," said collaborator Matthew Knight.

Looking to the past on the other hand, brings another possible scenario. If the comet behaved similarly on previous orbits, it could have been rotating so fast that the nucleus might have broken, allowing more gas to escape and causing an increase in brightness for a short period of time. Such an outburst was observed in 2001.

The preliminary results were presented during the 49th Meeting of the American Astronomical Society Division for Planetary Sciences held in Provo, Utah. The full team consists of David Schleicher from Lowell Observatory, Nora Eisner from the University of Sheffield, Matthew Knight from the University of Maryland, and Audrey Thirouin also from Lowell Observatory.

IRON AND ICE
Team led by UCLA astrophysicist observes primitive comet 2 billion kilometres from the sun
Los Angeles CA (SPX) Oct 09, 2017
A team of astronomers led by UCLA professor David Jewitt has identified a "special comet" 2.5 billion kilometres from the sun. No other comet heading toward our sun has ever been seen at such a great distance. Jewitt said the discovery will enable scientists to monitor the developing activity of a comet over an extraordinary range of distances. C/2017 K2 (PANSTARRS), or K2 for short, ... read more

Related Links
Lowell Observatory
Asteroid and Comet Mission News, Science and Technology


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

IRON AND ICE
Russia launches cargo ship to space station

Roscosmos: International Space Exploration to Continue Despite Geopolitical Situation

US spacewalkers install 'new eyes' at space station

NASA May Extend BEAM's Time on the International Space Station

IRON AND ICE
First Four Space Launch System Flight Engines Ready To Rumble

Rocket motor for Ariane 6 and Vega-C is cast for testing

RS-25 Engines Ready for Maiden Flight of NASA's Space Launch System

Russia May Adjust Space Program to Construct Super-Heavy Carrier Rocket

IRON AND ICE
What NASA's simulated missions tell us about the need for Martian law

Mimetic Martian water is highly pressurized, experiments show

Debate over Mars exploration strategy heats up in astrobiology journal

Webcam on Mars Express surveys high-altitude clouds

IRON AND ICE
China launches three satellites

Mars probe to carry 13 types of payload on 2020 mission

UN official commends China's role in space cooperation

China's cargo spacecraft separates from Tiangong-2 space lab

IRON AND ICE
Eutelsat's Airbus-built full electric EUTELSAT 172B satellite reaches geostationary orbit

Turkey, Russia to Enhance Cooperation in the Field of Space Technologies

SpaceX launches 10 satellites for Iridium mobile network

Lockheed Martin Completes First Flexible Solar Array for LM 2100 Satellite

IRON AND ICE
Understanding rare earth emulsions

Missing link between new topological phases of matter discovered

Space radiation won't stop NASA's human exploration

Saab upgrading Norwegian radars under NATO contract

IRON AND ICE
Astronomers find potential solution into how planets form

A star that devoured its own planets

Giant Exoplanet Hunters: Look for Debris Disks

Are Self-Replicating Starships Practical

IRON AND ICE
Haumea, the most peculiar of Pluto companions, has a ring around it

Ring around a dwarf planet detected

Helicopter test for Jupiter icy moons radar

Solving the Mystery of Pluto's Giant Blades of Ice




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement