Space
The Star Betelgeuse Went a Little Dim in 2019. Astronomers Think They Know Why
The star Betelgeuse visibly dimmed in 2019. Now, a new analysis reveals why: Betelgeuse blew out and is still recovering.
The red supergiant star, which is about 530 light-years from Earth, is among the brightest in the night sky. The star forms the shoulder of the constellation Orion (The Hunter).
It’s also geriatric: Betelgeuse is nearing the end of its stellar life and will eventually explode in a supernova visible from Earth, though it might take another 100,000 years, according to 2021 research.
In late 2019, Betelgeuse’s light started to dim. By February 2020, it had lost two-thirds of its normal luminosity as seen from Earth.
Scientists studying the bizarre dimming concluded that the star itself was not imminently going supernova but that a giant dust cloud had obscured some of the star’s light.
Now, scientists using the Hubble Space Telescope have revealed that this dust cloud was the result of an enormous ejection from the star’s surface: A plume more than 1 million miles (1.6 million kilometers) across may have risen from inside the star, producing the equivalent of a starquake, a shock that blew out a chunk of the star’s surface 400 million times larger than those usually seen in the sun‘s coronal mass ejections, the team reported in a paper published to the preprint database arXiv and accepted by The Astrophysical Journal for publication.
“Betelgeuse continues doing some very unusual things right now; the interior is sort of bouncing,” study author Andrea Dupree, associate director of the Harvard & Smithsonian Center for Astrophysics, said in a statement.
This is uncharted territory in star science, Dupree said.
“We’ve never before seen a huge mass ejection of the surface of a star,” she said. “We are left with something going on that we don’t completely understand. It’s a totally new phenomenon that we can observe directly and resolve surface details with Hubble. We’re watching stellar evolution in real time.”
The new research also incorporated information from a variety of other stellar observatories, such as the STELLA Robotic Observatory in Spain’s Canary Islands, and NASA’s Earth-orbiting STEREO-A spacecraft.
By piecing together different types of data, Dupree and her team were able to put together a narrative of the blowout and its aftermath.
The eruption blew off a chunk of the star’s lower atmosphere, the photosphere, leaving behind a cool spot that was further occluded by the dust cloud from the blowout.
Above: In the first two panels, as seen in ultraviolet light with the Hubble Space Telescope, a bright, hot blob of plasma is ejected from the emergence of a huge convection cell on the star’s surface. In panel three, the outflowing, expelled gas rapidly expands outward. It cools to form an enormous cloud of obscuring dust grains. The final panel reveals the huge dust cloud blocking the light (as seen from Earth) from a quarter of the star’s surface.
The chunk of photosphere was several times the mass of Earth’s moon, according to NASA’s statement.
This cool spot and dust cloud explain why Betelgeuse’s light dimmed. The star is still feeling the reverberations, the researchers found.
Before the eruption, Betelgeuse had a pulsating pattern, dimming and brightening on a 400-day cycle. That cycle is now gone, at least temporarily.
It’s possible that the convection cells inside the star are still sloshing around, disrupting this pattern, the researchers found.
The star’s outer atmosphere may be back to normal, but its surface may still be jiggling like Jell-O, according to NASA’s Hubblesite.
The eruption isn’t evidence that Betelgeuse will go supernova anytime soon, the researchers said, but it does show how old stars lose mass.
If Betelgeuse does finally die in a stellar explosion, the light will be visible in the daytime from Earth, but the star is too far away to have any other impacts on our planet.
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This article was originally published by Live Science. Read the original article here.
Recently, a group of experts from Harvard University, led by physics
professor Avi Loeb, announced the possible presence of alien space
debris in Earth’s orbit, reports the Daily Star.
Leading
space research expert Professor Loeb is confident that the discovery of
such “interstellar objects could help expand our knowledge of possible
alien civilizations and technologies. A team of scientists is conducting
research to confirm that some of the objects in our orbit may be
connected to other star systems.
During an interview with Live
Science, Professor Loeb explained that these objects could enter the
solar system from interstellar space, defying Jupiter’s gravitational
pull and occupying limited orbits around the sun.
Some of them may
have technological origins similar to the probes sent by mankind into
interstellar space, such as Voyager 1 and Voyager 2, Pioneer 10 and 11
and New Horizons.
However,
despite these interesting assumptions, Professor Loeb did not specify
what specific objects he was talking about. In his research report, he
notes that there could be “a significant number” of potentially
detectable objects in Earth’s orbit.
To confirm their assumptions,
the team of scientists uses computer simulations and the Vera Rubin
Observatory (Chile) with a high-resolution camera of 3.2 billion pixels.
This will allow for regular observations of the Southern sky and the
possibility of detecting several captured objects about the size of a
football field.
It is assumed that these interstellar objects passed through the
boundaries of the solar system and may carry unique information about
other civilizations and their technologies. If we could confirm the
origin of these objects, the mysteries that open before us, this would
be a real breakthrough in space exploration.
Professor Loeb
expresses hope that the new research will not only help expand our
knowledge of extraterrestrial technologies, but may also lead to the
discovery of new alien civilizations . Answers to such questions can be
of global significance and influence our understanding of the place of
mankind in the Universe.
And
while there are still many questions and assumptions, the study by
Professor Loeb and his team opens a new chapter in space exploration.
Each new discovery can be the key to deciphering the mysteries of the
cosmos and the possibility of encountering alien life forms.
Betelgeuse, a red giant on the brink of death, continues to show
unusual behavior. After the Great Blackout, which occurred in late 2019
and early 2020, the star became unusually bright. It is now the seventh
brightest star in the sky, while it normally ranks tenth. This has led
to speculation that Betelgeuse is preparing to explode in a
spectacularly large supernova.
However, scientists believe it’s too early to tell, and it’s likely
that this behavior is due to ongoing fluctuations after the Great
Blackout of 2019, and the star will return to normal within a decade.
Betelgeuse is one of the most interesting stars in the sky. It is
about 700 light-years from Earth and is a red giant in the last stage of
its life. It is also an unusual star for a red giant because it was
previously a monster blue-white O-type star, the most massive class of
stars.
Betelgeuse has changed its spectral type because it has almost
exhausted its hydrogen reserves. It now burns helium into carbon and
oxygen and has expanded to a gigantic size: about 764 times the size of
the Sun and about 16.5 to 19 times its mass.
Eventually it will run out of fuel to burn, become a supernova, eject
its outer material, and its core will collapse into a neutron star.
Before the Great Blackout, Betelgeuse also had periodic fluctuations
in brightness. The longest of these cycles is about 5.9 years and the
other is 400 days. But it seems that the Great Blackout caused changes
in these oscillations.
A new paper by astrophysicist Morgan McLeod of the
Harvard-Smithsonian Center for Astrophysics has shown that the 400-day
cycle appears to have been halved. This pulsational cycle is probably
caused by expansion and contraction within the star. According to
simulations carried out by MacLeod and his colleagues, the convective
flow inside Betelgeuse may have risen and become material that separates
from the star.
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