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An unusual horned comet known for its series of recent outbursts will be visible in the night sky for the rest of March – and astronomers expect the so-called Devil’s Comet to make a rare appearance during the total solar eclipse on April 8.
Exactly why the dynamic comet takes a shape that draws comparisons to the Millennium Falcon spacecraft from the “Star Wars” films while being explosively active is still a mystery to scientists. But the celestial body only completes one orbit around the sun about every 71 years, similar to Halley’s Comet, making the chance to study it up close a unique opportunity.
Given that the comet will not pass Earth again for decades, collective observations by astronomers could provide important insights into Pons-Brooks’ true nature and behavior.
Officially known as Comet 12P/Pons-Brooks, the celestial body will make its closest pass to the Sun on April 21, coming within 74.4 million miles (119.7 million kilometers) of our star. The comet will then make its closest pass to Earth on June 2, but will be 224.4 million kilometers from our planet and will not pose a risk.
For those in the Northern Hemisphere, the last 10 days of March will offer the best views, according to Dr. Paul Chodas, manager of the Center for Near-Earth Object Studies, and Davide Farnocchia, navigation engineer, at NASA’s Jet Propulsion Laboratory in Pasadena, California.
“The comet will brighten somewhat as it approaches the Sun, and should be visible low in the west to the naked eye about an hour after sunset,” said a joint email from Chodas and Farnocchia. “You need to go to a location that is far away from the city lights and with a clear view of the western horizon. It would be advisable to use binoculars as the comet may be difficult to locate without them.”
After April 2, the comet is on course to move into the sky during the day and will no longer be visible to skygazers at night – but it will be visible when the moon’s shadow temporarily obscures the face of the sun on April 8. hidden from view.
“The comet would be about 25 degrees away from the eclipsed Sun,” Chodas and Farnocchia said via email. “The comet should be fairly easy to find during the total solar eclipse, as well as some of the planets, but the main focus during those four minutes should be on the eclipse itself!”
After the comet makes its closest approach to the Sun, known as perihelion, the celestial body will shift into the southern night sky in late April and will only be visible to those in the Southern Hemisphere.
Two prolific discoverers, Jean-Louis Pons and William Robert Brooks, first independently observed the Devil’s Comet in 1812. But the comet likely made many journeys around the Sun over thousands of years, long before astronomers thought of comets as anything else. thought. then “something strange in the atmosphere,” said Dr. Dave Schleicher, an astronomer at the Lowell Observatory in Arizona.
Astronomers estimate the massive comet has a diameter of between 10 and 20 kilometers, said astronomer Dr. Teddy Kareta, a postdoctoral fellow at the Lowell Observatory.
The rare visitor has a green appearance that is typical of most comets, because they contain diatomic carbon molecules that absorb sunlight and emit a color that appears green from our perspective, Schleicher said.
A series of cosmic eruptions
Pons-Brooks recently caught the attention of astronomers after exhibiting intriguing behavior that caused the comet to take on a horned appearance and drift through our solar system.
The comet has experienced a number of outbursts over the past eight months, emitting gas and dust. While such releases are not unusual in comets, and a crescent or Pac-Man shape has been observed in other comets, it’s hard to say what’s normal for Pons-Brooks.
“I would say it’s somewhat unusual given the number of eruptions it’s had,” Schleicher said. “On the other hand, it’s not like you have good records from the past that really let you know what’s typical. And I suspect, given the fairly large number of eruptions that have occurred over the last eight months, that this is very clearly a common occurrence for Pons-Brooks.”
Comets are chunks of dust, rock and ice, essentially frozen remnants from the formation of the solar system. They also contain frozen elements such as carbon dioxide and carbon monoxide.
Comets become warmer and brighter as they approach the sun, and some frozen gases stored in comets don’t have to warm up much before they start turning to vapor, Schleicher said.
“We obviously think the ultimate driver is solar heating,” he said. “The comet is coming in; it has been in the freezer for years. The heat will work its way from the surface to where the carbon dioxide or carbon monoxide ice is.”
Astronomers suspect that Pons-Brooks eruptions occurred over the course of repeated events, with heat vaporizing material inside the comet, causing pressure to build and break through the surface. Although an explosion of gas wouldn’t be visible in telescopes, the dust it kicks up would cause the kind of events observed from Pons-Brooks, Schleicher said.
Scientists have traced the jets of material observed during the comet’s outburst to two source regions on its surface. Astronomers are puzzled why “the entire surface doesn’t go off like crazy,” Schleicher said.
The observations imply that ice has settled over most of the surface, or that the ice has evaporated, leaving only dirt behind, but astronomers “aren’t entirely sure which of these mechanisms are running the show,” he said.
What we can learn from comets
An overlapping series of events likely contributed to Pons-Brooks’s distinctive appearance, but it could also be due to our perspective of the comet, Kareta said.
“These are three-dimensional objects,” Kareta said. “When we take images of the night sky, we take them in a limited number of colors, all flattened in two dimensions. This makes things that make perfect sense to you, when you can go up and walk around and see it from a number of different perspectives, look a lot more complicated than they actually are.
Astronomers are observing Pons-Brooks in hopes of revealing more details about its rotation rate, or the speed at which comets spin as they move through space. Pons-Brooks has a rotation period of 57 hours, which is longer than expected, and astronomers want to know whether the jets of material released from the comet speed it up or slow it down.
But Schleicher recommends paying attention to the comet now rather than during the eclipse.
“In all my years I have seen many comets. I’ve only seen two total solar eclipses, and this would be #3. The first one I saw was in 1991, from Baja. And that was just extraordinary. I remember realizing that it is no wonder that this is considered the most beautiful sight in the sky that any human being on earth can see. Go up the path and see it in its entirety. You don’t understand it until you’ve seen one.”
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