Is bright Comet ATLAS disintegrating?

Comet C/2019 Y4 (ATLAS) has been fainter during the last few nights. It’s possible it’s disintegrating (as comets sometimes do), although it’s still possible ATLAS will survive. Details here.Sharing is caring!

Images of Comet ATLAS – taken on April 5, 2020 – show an elongation of the comet’s nucleus. The elongation is aligned with the axis of the comet’s tail. Astronomers have seen before that comets exhibit this sort of elongation shortly before disintegrating. Is that what’s happening? Image via astronomers Quanzhi Ye (University of Maryland) and Qicheng Zhang (Caltech)/ Ningbo Education Xinjiang Telescope.

Updated April 6, 2020.

Recent observations of Comet C/2019 Y4 (ATLAS) show that it’s fading in brightness. According to observers’ reports, after gradually brightening to magnitude 8 as it crossed Mars’ orbit, the comet has appeared fainter during the last few nights. It has sunk to a magnitude of around 8.8 to 9.2 (the bigger the number, the fainter the sky object). Is Comet ATLAS disintegrating? Are our hopes for a bright comet – or even one visible to the eye – dashed? That’s a possibility … but not a certainty.

Astronomers Quanzhi Ye (University of Maryland) and Qicheng Zhang (Caltech) submitted an astronomical telegram titled Possible Disintegration of Comet C/2019 Y4 (ATLAS). According to their telegram:

We report the possible disintegration of comet C/2019 Y4 (ATLAS), revealed by the public monitoring program carried out by the 0.6-m Ningbo Education Xinjiang Telescope (NEXT). Images taken on UT 2020 April 5.6-5.9 showed an elongated pseudo-nucleus measuring about 3 arcsec in length and aligned with the axis of the tail, a morphology consistent with a sudden decline or cessation of dust production, as would be expected from a major disruption of the [comet’s] nucleus.

Does this mean the end of Comet C/2019 Y4 (ATLAS)? Not necessarily. Time and time again, comets have shown themselves to be erratic and unpredictable. In case Comet ATLAS does remain visible – and in one piece – EarthSky shares some charts below to help you find the celestial visitor.

View at EarthSky Community Photos. | Photographer Steve Pauken in Bisbee, Arizona, said: “Comet C/2019-Y4 Atlas on April 2. Getting a bit brighter.”

Original article is below. Be aware that, if the comet has faded, all bets are off for brightness predictions.

A recently discovered comet is getting the attention of astronomers and sky enthusiasts as it’s become brighter than expected in the last few days. Astronomers using the ATLAS (Asteroid Terrestrial-impact Last Alert System) in Hawaii discovered Comet C/2019 Y4 (ATLAS) on December 28, 2019. As of mid-late March, it shines at about the brightness of an 8th-magnitude star – not visible to the eye yet – but within reach of medium-sized telescopes in dark skies. The comet is currently crossing Mars’ orbit and is approaching the inner solar system. As it gets closer to us, it’ll get brighter still. You’ll find charts for observers at the bottom of this post.

Comet ATLAS should become bright enough to be easily visible in binoculars, and perhaps bright enough to be seen with the unaided eye from dark sky locations.

Just know that comets are notoriously erratic and inherently unpredictable! We will have to wait to see how Comet ATLAS performs.