Comet C/2021 A1 (Leonard) is seen next to globular star cluster M3 in this image taken by Adam Block at UArizonas Mount Lemmon Sky. Credit: Adam Block/Steward Observatory/University of Arizona
The brightest comet of the year, named “Leonard” after the University of Arizona scientist who discovered it, is paying one last see to Earths area this month, before leaving the planetary system permanently.
Now is the best time to get a peek of Comet C/2021 A1, better called Comet Leonard. Its named for its discoverer, Gregory Leonard, a senior research study professional at the University of Arizona Lunar and Planetary Laboratory.
Every night with clear skies, astronomers with LPLs Catalina Sky Survey scan the sky for near-Earth asteroids– space rocks with the potential of venturing close to Earth at some time.
” Beginning December 13, this comet will appear really low above the horizon just after sunset,” Leonard said. Comet Leonard is no complete stranger to the inner solar system. Its very first encounter with the sun flung Comet Leonard back into the depths of area, just to turn around about 40,000 years later and embark on another trip towards the sun. On this check out, however, Comet Leonard is taking a trip without a return ticket.
” This is the last time we are going to see the comet,” Leonard stated.
During one such routine observation work on Jan. 3, Leonard spotted a fuzzy spot of light tracking across the starfield background in a series of 4 images taken with the 1.5-meter telescope at the summit of Mount Lemmon. The dots fuzzy appearance, combined with the fact that it had a tail, was a dead free gift that he was taking a look at a comet, he said.
Gregory Leonard discovered the comet using the Catalina Sky Surveys 1.5-meter (60-inch) telescope on Mount Lemmon. Credit: Camillo Scherer
” The fact that the tail revealed up in those images was impressive, considering that the comet had to do with 465 million miles out at that point, about the very same range as Jupiter,” he said.
The majority of long-period comets such as Comet Leonard hail from the Oort Cloud, a large area surrounding our solar system at distances no spacecraft has actually ever come close to, not even the two Voyager probes, which have actually formally left the planetary system and got in interstellar space.
Out there, suspended in the large interstellar void where temperatures are close to absolute zero, are billions of orbiting comets balanced in a delicate tug-of-war of exceptionally weak gravitational forces in between the far-off sun and the rest of the Milky Way. Slight perturbations of this precarious balance of forces may push a chunk of ice and dust out of the Oort Cloud and send it onto a trajectory toward the sun.
” When the tug-of-war is won by the gravity of our solar system, a things may begin moving inwards, accelerating as it gets closer to the sun,” Leonard discussed.
A Meteor Shower on Venus?
Comet Leonard made its closest technique to Earth on Dec. 12, at which point it was still more than 21 million miles far from Earth, about 88 times the range from Earth to the moon. The comet currently can be spotted low in the night sky, simply after sunset.
On Dec. 17, the comet is anticipated to pass extremely near to Venus in what Leonard calls a cosmic close call.
” There is a small possibility Venus will pass close enough to the comets course where it might pick up some dust grains in its atmosphere, producing a meteor shower on our surrounding planet,” he said.
Speaking of Venus, the “night star,” as its often called, is presently plainly visible in the southwestern sky just around sundown and might make for an useful guidepost, helping sky watchers to find the comet, Leonard stated.
” Beginning December 13, this comet will appear extremely low above the horizon simply after sundown,” Leonard said. “It will skim across the west-southwestern horizon between now up till around Christmastime. The reality that its so near the horizon makes this comet a bit tough to observe.”
Still, Leonard motivates people to give it a shot, explaining that observers may benefit from an effect called forward spreading: As it comes closer to the sun, the comets tail and “coma”– a cloud of dust and gas– may scatter the sunlight from behind, possibly dramatically improving the comets brightness.
” I feel there is going to be something to be seen even for the casual observer,” Leonard stated. “Find yourself a dark sky with a great view of the horizon, bring binoculars and I think you might be rewarded.”
Not its First Visit to Earths Neighborhood
Comet Leonard is no stranger to the inner solar system. Its very first encounter with the sun flung Comet Leonard back into the depths of space, just to turn around about 40,000 years later on and embark on another trip towards the sun.
” This is the last time we are visiting the comet,” Leonard stated. “Its speeding along at escape speed, 44 miles per second. After its slingshot around the sun, it will be ejected from our planetary system, and it may stumble into another star system countless years from now.”
The Catalina Sky Survey operates two telescopes at its Mount Lemmon station to search the night skies for near-Earth asteroids. Credit: David Rankin
Leonard said it is unusual for a comet to burst into activity as far out from the sun as this one did when it initially appeared in Catalina Sky Surveys 1.5-meter reflector telescope, the workhorse discovery telescope for near-Earth asteroid and numerous comets. At the time, it was too far out for the sun to heat water ice– the main component of a lot of comets– into a streaming tail of vapor.
” Something other than water ice was being thrilled by the solar radiation and producing this rare atmosphere– potentially frozen carbon dioxide, carbon monoxide gas or ammonia ices,” he said.
The comet was incredibly faint, about 400,000 times dimmer than what human eyes can see, and was only gotten thanks to the combination of the telescopes large optics and exceptionally sensitive cam. The Catalina Sky Survey operates 4 telescopes in the Santa Catalina Mountains north of Tucson– one set of telescopes on Mount Bigelow and another pair on the summit of Mt. Lemmon.
Cherished for their look, comets are of terrific interest due to the fact that they function as messengers from the solar systems deep past. Maintaining product left over from when the sun and planets were born, these “unclean snowballs,” as they are in some cases called, contain ideas to the procedures that were at work when the solar system formed.
” As much as we have excellent science on comets, theyre still extremely unforeseeable with respect to their size, shape, chemical makeup and behavior,” Leonard said. “A wise and famous comet originator once said: Comets are like felines– both have tails and both do precisely what they want.”.