Nav: Home

Hubble captures rare active asteroid

March 28, 2019

Thanks to an impressive collaboration bringing together data from ground-based telescopes, all-sky surveys and space-based facilities -- including the NASA/ESA Hubble Space Telescope -- a rare self-destructing asteroid called 6478 Gault has been observed.

Clear images from the NASA/ESA Hubble Space Telescope have provided researchers with new insight into asteroid Gault's unusual past. The object is 4-9 kilometres wide and has two narrow, comet-like tails of debris that tell us that the asteroid is slowly undergoing self-destruction. Each tail is evidence of an active event that released material into space.

Gault was discovered in 1988. However, this observation of two debris tails is the first indication of the asteroid's instability. This asteroid one of only a handful to be caught disintegrating by a process known as a YORP torque . When sunlight heats an asteroid, the infrared radiation that escapes from its warmed surface carries off both heat and momentum. This creates a small force that can cause the asteroid to spin faster. If this centrifugal force eventually overcomes gravity, the asteroid becomes unstable. Landslides on the object can release rubble and dust into space, leaving behind a tail of debris, as seen here with asteroid Gault.

"This self-destruction event is rare", explained Olivier Hainaut (European Southern Observatory, Germany). "Active and unstable asteroids such as Gault are only now being detected by means of new survey telescopes that scan the entire sky, which means asteroids such as Gault that are misbehaving cannot escape detection any more."

Astronomers estimate that among the 800,000 known asteroids that occupy the Asteroid Belt between Mars and Jupiter, YORP disruptions occur roughly once per year. The direct observation of this activity by the Hubble Space Telescope has provided astronomers with a special opportunity to study the composition of asteroids. By researching the material that this unstable asteroid releases into space, astronomers can get a glimpse into the history of planet formation in the early ages of the Solar System.

Understanding the nature of this active and self-destructive object has been a collaborative effort involving researchers and facilities around the world. The asteroid's debris tail was first detected by the University of Hawai?i/NASA ATLAS (Asteroid Terrestrial-Impact Last Alert System) telescopes in the Hawaiian Islands on 5 January 2019. Upon review of archival data from ATLAS and UH/NASA Pan-STARRS (Panoramic Survey Telescope and Rapid Response System), it was found that the object's larger tail of debris had been observed earlier in December 2018. Shortly thereafter, in January 2019, a second, shorter tail was seen by various telescopes, including the Isaac Newton, William Herschel, and ESA OGS Telescopes in La Palma and Tenerife, Spain; the Himalayan Chandra Telescope in India; and the CFHT in Hawai?i. Subsequent analysis of these observations suggested that the two events that produced these debris trails occurred around 28 October and 30 December 2018, respectively. These tails will only be visible for only a few months, after which the dust will have dispersed into interplanetary space.

Follow-up observations were then made by various ground-based telescopes. These data were used to deduce a two-hour rotation period for Gault, which is very close to the critical speed at which material will begin to tumble and slide across the asteroid's surface before drifting off into space.

"Gault is the best 'smoking-gun' example of a fast rotator right at the two-hour limit", explained lead author Jan Kleyna (University of Hawai?i, USA). "It could have been on the brink of instability for 10 million years. Even a tiny disturbance, like a small impact from a pebble, might have triggered the recent outbursts."

Hubble's sharp imaging provided valuable detail regarding the asteroid's activity. From the narrow width of the streaming tails, researchers inferred that the release of material took place in short episodes lasting from a few hours to a couple of days. From the absence of excess dust in the immediate vicinity of the asteroid, they concluded that the asteroid's activity was not caused by a collision with another massive object. Researchers hope that further observations will provide even more insight into this rare and curious object.

The team's results have been accepted for publication in the Astrophysical Journal Letters.
-end-
More information

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

The research team's work is presented in the scientific paper "The Sporadic Activity of (6478) Gault: A YORP driven event?", which will be published in the Astrophysical Journal Letters.

ATLAS (Asteroid Terrestrial-impact Last Alert System) is an asteroid impact early warning system being developed by the University of Hawai'i and funded by NASA. It consists of two telescopes, 100 miles apart, which automatically scan the whole sky several times every night looking for moving objects.

The international team of astronomers in this study consists of Jan T. Kleyna (University of Hawai'i Institute for Astronomy, USA), Olivier R. Hainaut(European Southern Observatory, Germany), Karen J. Meech (University of Hawai'i Institute for Astronomy, USA), Henry H. Hsieh (Planetary Science Institute, USA, & Academia Sinica Institute of Astronomy and Astrophysics, Taiwan), Alan Fitzsimmons (Queen's University Belfast Astrophysics Research Centre, UK), Marco Micheli (European Space Agency Near Earth Object Coordination Centre, Italy, & National Institute for Astrophysics - Osservatorio Astronomico di Roma, Italy), Jacqueline V. Keane (University of Hawai'i Institute for Astronomy, USA), Larry Denneau (University of Hawai'i Institute for Astronomy, USA), John Tonry (University of Hawai'i Institute for Astronomy, USA), Aren Heinze (University of Hawai'i Institute for Astronomy, USA), Bhuwan C. Bhatt(Indian Institute for Astrophysics, India), Devendra K. Sahu (Indian Institute for Astrophysics, India),

Detlef Koschny (European Space Agency European Space Research and Technology Centre, the Netherlands & Near Earth Object Coordination Centre, Italy, & Technical University of Munich, Germany), Ken W. Smith (Queen's University Belfast Astrophysics Research Centre, UK), Harald Ebeling (University of Hawai'i Institute for Astronomy, USA), Robert Weryk (University of Hawai'i Institute for Astronomy, USA), Heather Flewelling (University of Hawai'i Institute for Astronomy, USA), and Richard J. Wainscoat (University of Hawai'i Institute for Astronomy, USA).

Image credit: NASA, ESA, NASA, ESA, K. Meech and J. Kleyna (University of Hawaii), O. Hainaut (European Southern Observatory), L. Calçada

Links

* Images of Hubble - http://www.spacetelescope.org/images/archive/category/spacecraft/

* Hubblesite release - http://hubblesite.org/news_release/news/2019-22

Contacts

Jan Kleyna
Institute for Astronomy
Honolulu, HI, USA
Tel: +1 808 956-0797
Email: kleyna@hawaii.edu

Olivier Hainaut
European Southern Observatory
Garching bei München, Germany
Tel: +49 89 3200 6752
Email: ohainaut@eso.org

Dr. Karen Meech
Institute for Astronomy
Honolulu, HI, USA
Tel: +1-808-956-6828
Email: meech@ifa.hawaii.edu

Bethany Downer
ESA/Hubble, Public Information Officer
Garching bei München, Germany
Email: bethany.downer@partner.eso.org

ESA/Hubble Information Centre

Related Hubble Space Telescope Articles:

Kepler Space Telescope's first exoplanet candidate confirmed
An international team of astronomers announced the confirmation of the first exoplanet candidate identified by NASA's Kepler Mission.
Space telescope detects water in a number of asteroids
Using the infrared satellite AKARI, a Japanese research team has detected the existence of water in the form of hydrated minerals in a number of asteroids for the first time.
The Hubble Space Telescope discovers the most distant star ever observed
An international team, including researchers from the Instituto de Astrofísica de Canarias (IAC) and the University of La Laguna (ULL), participated in the discovery of a star at a distance of nine billion lightyears from Earth.
ASU astronomers to build space telescope to explore nearby stars
A new ASU-led mission will launch a small satellite telescope into space to study the environment in other solar systems around the Galaxy's most common type of star.
James Webb Space Telescope's laser-focused sight
About 1 million miles away from the nearest eye surgeon, NASA's James Webb Space Telescope will be able to perfect its own vision while in orbit.
Hubble is paving scientific paths for NASA's James Webb Space Telescope
NASA's Hubble Space Telescope is helping identify potential celestial targets for the James Webb Space Telescope through a series of preparatory science observations to be completed before Webb is ready to make observations of its own.
Keeping NASA's James Webb Space Telescope in the dark
This bunny-suited technician is performing the important task of ensuring no unwanted infrared light interferes with the optical testing of NASA's James Webb Space Telescope inside of Chamber A at NASA's Johnson Space Center in Houston.
New way to weigh a white dwarf: Use Hubble Space Telescope
For the first time, astronomers have used a novel method to determine the mass of a type of star known as a 'white dwarf' -- the shrunken corpse of a dead star that used to be like our sun.
NASA's James Webb space telescope completes acoustic and vibration tests
At NASA's Goddard Space Flight Center in Greenbelt, Maryland the James Webb Space Telescope team completed the acoustic and vibration portions of environmental testing on the telescope.
Probing seven worlds with NASA's James Webb Space Telescope
With the discovery of seven earth-sized planets around the TRAPPIST-1 star 40 light years away, astronomers are looking to the upcoming James Webb Space Telescope to help us find out if any of these planets could possibly support life.
More Hubble Space Telescope News and Hubble Space Telescope Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

Risk
Why do we revere risk-takers, even when their actions terrify us? Why are some better at taking risks than others? This hour, TED speakers explore the alluring, dangerous, and calculated sides of risk. Guests include professional rock climber Alex Honnold, economist Mariana Mazzucato, psychology researcher Kashfia Rahman, structural engineer and bridge designer Ian Firth, and risk intelligence expert Dylan Evans.
Now Playing: Science for the People

#541 Wayfinding
These days when we want to know where we are or how to get where we want to go, most of us will pull out a smart phone with a built-in GPS and map app. Some of us old timers might still use an old school paper map from time to time. But we didn't always used to lean so heavily on maps and technology, and in some remote places of the world some people still navigate and wayfind their way without the aid of these tools... and in some cases do better without them. This week, host Rachelle Saunders...
Now Playing: Radiolab

Dolly Parton's America: Neon Moss
Today on Radiolab, we're bringing you the fourth episode of Jad's special series, Dolly Parton's America. In this episode, Jad goes back up the mountain to visit Dolly's actual Tennessee mountain home, where she tells stories about her first trips out of the holler. Back on the mountaintop, standing under the rain by the Little Pigeon River, the trip triggers memories of Jad's first visit to his father's childhood home, and opens the gateway to dizzying stories of music and migration. Support Radiolab today at Radiolab.org/donate.