Avid skywatchers know there’s always something to see in the night’s sky. But this week could be special. Two comets will brush past our blue marble today and tomorrow. Comets 252P/LINEAR and P/2016 BA14 (PANSTARRS) will enter the record books as two of the closest comets in recent history.
Here’s what you need to know.
They are close
Comet 252P will fly by on Monday at a distance of 5.2 million kilometers. BA14 will cruise by a day later at 3.5 million kilometers. To put that in perspective, Halley’s Comet was 22.4 million kilometers from Earth during its breathtaking fly by in 1910. And it was the first time a comet had ever been photographed.
That puts comet 252P in the top 10 of the closest approaching comets in recorded history. BA14 will become the second closest comet since Lexell’s Comet in 1770.
But, they are small
Comet 252P is the bigger of the pair but measures just 230 meters across. That’s small for a comet too. Comet 67/P Chruyumov-Gerasimenko, the one the Rosetta probe is orbiting, is 4 kilometers across. Halley’s comet is about 16 kilometers long.
You might be able to see comet 252P
252P/LINEAR is the one that has the astronomy community buzzing. It’s just 230 meters across, but it is exploding in brightness. In the past week, the comet’s magnitude has jumped from +11th magnitude to 6th. In layman terms? 252P/LINEAR is an easy target for binoculars and may ultimately be visible to the naked eye in darker skies.
Why the big jump in brightness? It could be a piece broke off, or exposed ice turned to gas. Whatever the case, it’s giving astronomers a good show. The question is, will that show continue? We’ll have to wait and see. Sky & Telescope has a great post detailing when folks in the Northern Hemisphere will have the best chance of seeing comet 252P.
If you want to catch the action during closest approach, head on over to Virtual Telescope to watch live. The event starts at 5:00 pm EST.
Comet P/2016 BA14 was first classified as an asteroid
BA14 is a newcomer for astronomers. It was first discovered in January and was initially thought to be an asteroid. But follow-up observations in February revealed a tail. And the pair could be related. Two comets with almost the same orbital properties? It does suggest the pair was once one comet. If they once were a larger comet, it’s likely a chunk of 252P broke away to become BA14.
Astronomers hope to solve this little riddle with the help of the Hubble Space Telescope. During this week’s closest approach, the Hubble will take a much closer look at 252P. Spectra gathered from these observations should show if the comet’s compositions are close enough to indicate they are related.
Hubble isn’t the only one getting ready to catch the record event. The Green Bank Telescope in West Virginia and one of NASA’s Deep Space Network dishes will probe BA14 to figure out what its nucleus looks like.
There might even be a meteor shower
According to SpaceWeather, the International Meteor Organization says there is a chance for a minor meteor shower on March 28-30. We don’t know much about meteors from 252P, but they would be very slow. If a meteor shower does happen, rates are expected to be no more than 5-10 per hour.
Comets BA14 and 252P might not impress with their size, but their close approaches will be remembered by amateur astronomers for years to come. And if 252P continues to surprise with its surging brightness, some of us might just be able to see it with our naked eye.
If you live in rural areas with a dark sky, grab a pair of binoculars and head outside later this week to try and catch 252P’s hazy glow. Be sure to check out Virtual Telescope later this evening for a look at BA14 during its closest approach.
Featured image credit: Justin Tilbrook (Astronomical Society of South Australia)