New images from the NASA/ESA Hubble Space Telescope of the long-period comet C/2019 Y4 (ATLAS), taken on April 20 and 23, 2020, provide the sharpest views yet that the comet’s nucleus is breaking apart into as many as 30 fragments.
Hubble resolved roughly 30 fragments of comet C/2019 Y4 (ATLAS) on April 20, 2020. Image credit: NASA / ESA / Hubble / D. Jewitt, University of California, Los Angeles / Q. Ye, University of Maryland.
Also known as comet ATLAS, C/2019 Y4 (ATLAS) is a comet with a near-parabolic orbit and an orbital period of about 6,000 years.
The comet was discovered on December 28, 2019 by the Asteroid Terrestrial-impact Last Alert System (ATLAS) in Hawaii.
It brightened quickly until mid-March, and some astronomers initially anticipated that it might be visible to the naked eye in May to become one of the most spectacular comets seen in the last two decades.
However, the object abruptly began to get dimmer, leading astronomers to speculate that its nucleus may be fragmenting, or even disintegrating.
Comet ATLAS is currently located inside the orbit of Mars, at a distance of approximately 145 million km (90.1 million miles) from Earth.
The new Hubble observations of its breakup on April 20 and 23 reveal that the broken fragments are all enveloped in a sunlight-swept tail of cometary dust.
Hubble resolved roughly 25 fragments of comet C/2019 Y4 (ATLAS) on April 23, 2020. Image credit: NASA / ESA / Hubble / D. Jewitt, University of California, Los Angeles / Q. Ye, University of Maryland.
“Their appearance changes substantially between the two days, so much so that it’s quite difficult to connect the dots,” said University of California, Los Angeles astronomer Dr. David Jewitt, leader of one of two teams who imaged the comet with Hubble.
“I don’t know whether this is because the individual pieces are flashing on and off as they reflect sunlight, acting like twinkling lights on a Christmas tree, or because different fragments appear on different days.”
“This is really exciting — both because such events are super cool to watch and because they do not happen very often,” added University of Maryland astronomer Dr. Quanzhi Ye, the leader of the second Hubble observing team.
“Most comets that fragment are too dim to see. Events at such scale only happen once or twice a decade.”
