An asteroid will temporarily eclipse one of the brightest stars in the sky tonight

By Ashley Strickland, CNN

(CNN) — An asteroid in our solar system will temporarily block the light of Betelgeuse, one of the brightest stars in the night sky, Monday evening and early Tuesday morning.

The rare cosmic event will be visible to millions who live within a narrow strip that encircles half the globe and includes Mexico, southern Florida, Spain, Italy, Greece, Turkey and Central Asia.

Astronomers expect the event, called an occultation, around 8:17 p.m. ET. If you’re outside of the peak visibility zone or inclement weather blocks your view, The Virtual Telescope Project will be livestreaming the event from Italy beginning at 8 p.m. ET.

Betelgeuse is a red supergiant star about 700 light-years away that serves as the shoulder in the Orion constellation, according to NASA.

Given its intense luminosity, Betelgeuse is what astronomers call a first magnitude star. Set to pass between the star and Earth is Leona, a slightly oval-shaped asteroid located between the orbits of Mars and Jupiter. Leona is estimated to be about 50 miles (80 kilometers) by 34 miles (55 kilometers) in size.

While occultations, or asteroids temporarily blocking the light of stars, occur regularly, it is rare for space rocks to totally obscure the light of a first magnitude star from our perspective on Earth, said Gianluca Masi, astronomer and astrophysicist at the Bellatrix Astronomical Observatory in Italy and director of the Virtual Telescope Project.

Betelgeuse’s occultation is the type of event that occurs only once every few decades, Masi said.

Depending on the angular size of both the star and the asteroid, or the apparent size of each object as viewed from Earth, Betelgeuse may completely blink out of sight for a matter of seconds, not unlike a total solar eclipse, Masi said.

It’s possible that the asteroid won’t block all of the starlight from Betelgeuse as it passes between Earth and the giant star, creating a visible “ring of fire” similar to an annular solar eclipse.

“We do expect the event will last for 10 (to) 15 seconds in total, if and how long the star will totally disappear will depend (on) the annular or total coverage by Leona,” Masi said via email. “Likely, the star will fade and will be back gradually, not suddenly, because of the angular size of Betelgeuse.”

Betelgeuse is so bright that it can be seen with the naked eye, but Masi recommends viewing this event with binoculars or a telescope.

The occultation: A scientific opportunity

Astronomers are eager to observe the occultation because it will help them to collect scientific data on Leona and Betelgeuse that would be more difficult to gather otherwise.

Scientists observing the occultation could get more detailed and accurate measurements of the asteroid’s size and insight into what’s happening with Betelgeuse, which suddenly dimmed in 2019 and 2020, causing researchers to question whether the giant star was about to explode in a supernova.

While Betelgeuse is bright once more and a stellar eruption is widely thought to be the main culprit behind the dramatic dimming event, astronomers still question whether the star is on the path to an explosive end in the near future or thousands of years from now.

“We will be hopefully able to learn more about (Betelgeuse’s) large convective cells, driving its variable brightness,” Masi said. “It is one of the best candidates for a future supernova event, so the importance of the upcoming occultation is undoubtedly extremely high.”

Observing Betelgeuse, which is estimated to be about 10 million years old, allows astronomers to watch what happens late in the lifetime of a star. As Betelgeuse burns through fuel in its core, it has swollen to massive proportions, becoming a red supergiant, the latter phase of giant stars. When the star explodes, the event could be briefly visible during the daytime on Earth.

Masi is looking forward to collecting scientific observations of the occultation, which acts as a sort of preview for what our night sky will look like one day when Betelgeuse disappears after exploding.

“I cannot imagine seeing the legendary Orion constellation without its famous, orange shoulder, as it will be in the distant future, once Betelgeuse will have exploded as a supernova and faded to black,” Masi said.

The-CNN-Wire
™ & © 2023 Cable News Network, Inc., a Warner Bros. Discovery Company. All rights reserved.