Celestial News: Comet ZTF delights sky watchers | SteamboatToday.com

Celestial News: Comet ZTF delights sky watchers

Jimmy Westlake
Celestial News
Comet ZTF has spent the last week moving between the Big and Little Dippers. It is now making a beeline for the bright stars Capella and Aldebaran. Once the moon is out of the way, starting Monday, Feb. 6, 2023, the comet still should be faintly visible to the unaided eye and easy to spot in binoculars. This image and close-up inset were taken before dawn on Saturday, Jan. 28, 2023.
Jimmy Westlake/Courtesy photo

There’s a little comet in our winter sky that is generating a lot of excitement. Comet ZTF is the first comet to break the naked eye limit since beautiful Comet NEOWISE did in the summer of 2020.

Comets are like big, dirty snowballs out in space — leftovers from the formation of the sun and planets. When one of these snowballs falls in close to the sun, its icy surface begins to vaporize and release tons of gas and dust into space. The solar wind and the pressure of sunlight sweep this cloud of dust and gas away from the snowball, forming the comet’s majestic tail.

Traditionally, comets are named for their discoverer, and this new comet was discovered by a robotic telescope called the Zwicky Transient Facility, or ZTF, on March 2. Comet ZTF comes to us from the distant Oort Cloud, at the outer fringes of our solar system, and requires 500 centuries to complete one orbit. That means it has been falling toward the sun for the last 25,000 years.

It finally rounded the sun on Jan. 12 and began its outbound journey back to the Oort Cloud. But, on its way out, it passed only 27-million miles from Earth on Feb. 1. For comparison, that’s about 108 times farther from us than the moon, but it’s close enough to bring the comet into view without optical aid in dark skies.

Over the past week, Comet ZTF has been moving between the Big and Little Dippers in the northern sky. On Jan. 28, I was able to see it as a faint smudge against the starry sky with no optical aid. My 7×50 binoculars made the green comet easy to see. The key is knowing where to look.

You can still catch a glimpse of Comet ZTF before it disappears for the next 50,000 years, but you’ll need to wait for the bright moon to get out of the way. Moonlight is a comet killer.

The first opportunity will come just as darkness falls on Monday, Feb. 6, when Comet ZTF will be hiding near the bright star Capella, in the tiny triangle of stars known as “the Kids.” With each night after that, the moon rises later and later, but the comet gets farther and farther from Earth.

It will follow a path along a line connecting the bright stars Capella and Aldebaran, passing close to the planet Mars on Feb. 10 and Aldebaran on Feb. 13. It will remain visible in binoculars for another week or so.

If you hope to see a spectacular comet, then Comet ZTF will disappoint you. If, on the other hand, you want the challenge of finding a little fuzz ball at the edge of visibility in the winter sky, then Comet ZTF will delight you, too.

For more info

For information about astronomy-related events in Steamboat Springs, including public star parties at CMC’s Ball Observatory, contact physics and astronomy instructor Paul McCudden at pmccudden@coloradomtn.edu or 970-870-4537 or visit the SKY Club web page at ColoradoMtn.edu/skyclub.

Jimmy Westlake is adjunct professor of Physical Sciences at Colorado Mountain College and former director of the Rollins Planetarium at Young Harris College in Georgia and the St. Charles Parish Library Planetarium in Luling, Louisiana. His “Celestial News” column appears monthly in the Steamboat Pilot & Today. Check out Jimmy’s astrophotography website at JWestlake.com.

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