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Earlier this year, a visitor called 3I/Atlas grabbed the attention of astronomers around the world,as only the third-known interstellar object to visit our solar system. But there’s no reason for it to hog all of the limelight. A more local, icy space rock known as 220P/McNaught is currently streaking across the sky, and observers are taking note of its recent luminous transformation.
“[It] almost looks like a different comet,” astrophotographer Dan Bartlett explained on his AstroBin page.
220P/McNaught was discovered on May 20, 2004, by astronomer Robert McNaught while gazing through eastern Australia’s Siding Spring Observatory. An analysis revealed the periodic comet travels along a 5.5-year-long orbit predominantly controlled by Jupiter’s gravitational pull. This year, 220P/McNaught reached perihelion (its closest distance to the sun) on June 14 while just beyond the orbit of Mars. Since it is now traveling ahead of Earth, it’s most easily visible during dawn hours.
While generally a dimmer comet, recent activity has dramatically amplified 220P/McNaught’s brightness. In June, astronomers noted a surface eruption increased the comet’s luminosity by almost 10 magnitudes—making it around 8,000 times brighter than usual. This alone makes it one of the brightest comets ever observed, but 220P/McNaught flared by seven magnitudes yet again earlier in August. According to Universe Today, there’s a solid chance that the comet will grow more luminous at least one more time before it reaches its closest pass by Earth in October.
220P/McNaught will close out August positioned between the stars Lambda Ceti and Omicron Tauri, placing it high in the southern sky for the Northern Hemisphere through October. It will finally reach its farthest distance from the sun (its aphelion) on March 19, 2029, so its next perihelion appearance won’t occur until late 2031. However, given its luminous activity, it’s certainly possible that the comet is experiencing its death throes. If that’s the case, eagle-eyed observers may be able to witness the space rock disintegrate in real-time.
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