Two comets that will safely fly past Earth tomorrow may have more in common than their intriguingly similar orbits. They may be twins of a sort.
Comet P/2016 BA14 was discovered on 22 January, by the University of Hawaii’s PanSTARRS telescope on Haleakala, on the island of Maui. It was initially thought to be an asteroid, but follow-up observations by a University of Maryland and Lowell Observatory team with the Discovery Channel Telescope showed a faint tail, revealing that the discovery was, in fact, a comet. The orbit of this newly discovered comet, however, held yet another surprise. Comet P/2016 BA14 follows an unusually similar orbit to that of comet 252P/LINEAR, which was discovered by the Massachusetts Institute of Technology’s Lincoln Near Earth Asteroid Research (LINEAR) survey on 7 April 2000. The apparent coincidence may be an indication of twin nature in that comet. P/2016 BA14 is roughly half the size of comet 252P/LINEAR and might be a fragment that calved off sometime in the larger comet’s past.
“Comet P/2016 BA14 is possibly a fragment of 252P/LINEAR. The two could be related because their orbits are so remarkably similar,” says Paul Chodas, manager of NASA’s Center of NEO Studies (CNEOS) at the Jet Propulsion Laboratory in Pasadena, California. “We know comets are relatively fragile things, as in 1993 when comet Shoemaker-Levy 9 was discovered and its pieces linked to a flyby of Jupiter. Perhaps during a previous pass through the inner-solar system, or during a distant flyby of Jupiter, a chunk that we now know of as BA14 might have broken off of 252P.”
Observations made by the Hubble Space Telescope of comet 252P/LINEAR, and by NASA’s Infrared Telescope Facility of comet P/2016 BA14 will further investigate their possible twin nature.
Comet 252P/LINEAR, approximately 230 metres (750 feet) in size, will zip past Earth tomorrow [Monday 21 March] at a range of about 5.2 million kilometres (3.3 million miles). The following day, comet P/2016 BA14 will safely fly by our planet at a distance of about 3.5 million kilometres (2.2 million miles). This will be the second closest flyby of a comet in recorded history next to comet D/1770 L1 (Lexell) in 1770 and comet C/1983 H1 (IRAS-Araki-Alcock) in 1983.
The time of closest approach for comet 252P/LINEAR on 21 March will be around 5:14 am PDT (8:14 a.m. EDT). The time of closest approach for P/2016 BA14 on 22 March will be around 7:30 am PDT (10:30 a.m. EDT). While both comets will safely fly past at relatively close distances, anyone hoping to see them will need powerful, professional-grade telescopes, due to their relatively small size.
The approaches of these two comets will be the closest they come to Earth for the foreseeable future. “22 March will be the closest comet P/2016 BA14 gets to us for at least the next 150 years,” says Chodas. “Comet P/2016 BA14 is not a threat. Instead, it is an excellent opportunity for scientific advancement on the study of comets.”
The CNEOS website has a complete list of recent and upcoming close approaches, as well as all other data on the orbits of known NEOs, so scientists and members of the media and public can track information on known objects.