An icy visitor from the distant Oort Cloud is still in sight if you know exactly where to look for it. The comet is C/2017 K2 PanSTARRS. It’s in the name: the comet was discovered five years ago in 2017, an unusually long period of lead time, even for a long-period comet. Although it (sadly) never entered the inner solar system, mid-2022 is the best time to see the comet, and its distance also means that – unlike fast short-period comets – K2 PanSTARRS will linger in the sky for the rest of 2022 .
The comet was discovered by the prolific automated comet hunter Panoramic Survey Telescope and Rapid Response System (PanSTARRS) on the night of May 21, 2017. The distant (16 Astronomical Units-AU) discovery gave astronomers pause: only Comet (s) C /1995 O1 Hale- Bopp (in 1997), and the massive comet C/2014 UN271 Bernardinelli-Bernstein have ever been seen active at such a great distance. This is usually indicative of a prelude to a good show.
The orbit of the comet is probably dynamically new, which explains its stormy behavior while it is still far from the Sun. K2 PanSTARRS will reach perihelion 1.8 AU (just outside the orbit of Mars) later this year on December 19. This passage would also shorten the orbit down to “only” 18,000 years, with an outgoing aphelion 1400 AU far away.
Had comet K2 PanSTARRS entered the inner solar system like Hale-Bopp in the late 1990s, we would have been in for a real spectacular show. Ironically, Hale-Bopp passed us by about six months on the opposite side of Earth’s orbit – and still managed to put on an amazing show. Like K2 PanSTARRS, Hale-Bopp had its orbit shortened (thanks to Jupiter) from 4200 years (ingoing) to 2533 years (outgoing).
The comet in 2022
During the latter half of 2022, comet K2 PanSTARRS strolls in Ophiuchus and enters Scorpius the Scorpion, crossing the ecliptic plane south in late August. This means the time for Northern Hemisphere observers to check out Comet K2 PanSTARRS is now before we lose it in the southern sky. At the beginning of August, the comet rides high to the south at around 21:00 local time.
The comet, month by month in 2022
Comet K2 PanSTARRS already passed some red letter dates in early July when it passed 1.8 AU from Earth on July 14 and passed just 25′ from the globular cluster Messier 10 in Ophiuchus, giving many astrophotographers a nice photo op.
Here are the month-by-month fate dates for Comet K2 PanSTARRS for the rest of 2022:
(Note: unless otherwise noted, “close” means less than one degree).
4-Enters the constellation Scorpius
21-passes close to the bright (+2.5 magnitude) star Graffias (Beta Scorpii)
24-Nick’s constellation Libra
25-Returns in Scorpius
26-Crosses the ecliptic plane to the south
31-passes close to the bright (+2.3 magnitude) star Dschubba (Delta Scorpii)
3-Near the waxing crescent moon
9-Close to the star Pi Scorpii with +2.9 magnitude
17-Near the star Rho Scorpii at +3.8 magnitude
22-Moves into the constellation Lupus the Wolf
23-passer close to +12. magnitude Comet 73P/Schwassmann-Wachmann
11-passes close to the star Theta Lupi at magnitude +4.2
19-Crossing back to Scorpius
31-Crosses into the constellation Norma the carpentry square
12-Crosses into the constellation Ara the altar
14-Crossing the galactic plane southwards
29-Passes close to the +4.0 star Epsilon Arae
6 passes close to the +2.8 star Beta Arae
7-Close pass +3.3 star Gamma Arae
15-Enters the constellation Pavo the Peacock
19-When perihelion, 1.8 AU from the Sun
In 2023, the comet will fall back below +10. magnitude and lingers in the skies of the southern hemisphere as it recedes into the depths of the outer solar system, not to return again until after (mark your calendar) 20,000 AD.
Don’t miss Comet C/2017 K2’s appearance in 2022 as we all wait for the next big ‘Comet of the Century’.
This article was originally published on The universe today of David Dickinson. Read the original article here.