Scientists: Webb Telescope May Find Planet Around Closest Bright Star

Alpha Centauri, one of the two "Pointer Stars" that help stargazers find the Southern Cross in the ... More Southern Hemisphere, may have a planet in orbit around it. If it does, the Webb Telescope will find it — as long as it's Jupiter-sized.
The closest star to the sun, Proxima Centauri, has a planet. It may even have two planets. Proxima Centauri is located in the constellation Centaurus, visible only from the southern hemisphere, but it's a red dwarf star too small to be seen. That brightest star in Centaurus — and the third brightest in the entire night sky — is Alpha Centauri. It's two stars (Alpha Centauri A and Alpha Centauri B) orbiting each other, with Proxima Centauri orbiting them every 550,000 years, in a weird-sounding (but not rare) three-star solar system.
Does Alpha Centauri have planets around it? It's a Holy Grail among planet-hunters, mostly because Alpha Centauri is only 4.37 light-years distant. Since it's so close to the solar system, it's theoretically an ideal target for astrometry (the study of the movements of stars and celestial bodies), as well as for direct infrared imaging using the James Webb Space Telescope, two techniques that can detect planets orbiting distant stars — exoplanets. A new paper published this week in Research Notes of the American Astronomical Society details the use of the Webb telescope to study Alpha Centauri in February 2025. Although it didn't detect any planets, it provides glimpses of what may still be hiding around the star.
The Alpha Centauri star system — a triple-star planetary system.
According to the paper, the Webb telescope's Mid-InfraRed Instrument would have detected gas giant planets like Jupiter at about twice the Earth-sun distance from Alpha Centauri A if they were roughly similar to Earth's temperature.
It's tricky because, in a system with two bright stars, light pollution is always a problem. Although the Webb telescope has a coronagraph disc to block the light from the host star (by creating an artificial eclipse) to help it detect planets in the vicinity, it doesn't have two coronagraphs to use on two separate stars. Despite that — and despite Alpha Centauri Ac being five billion years old, meaning any planets in its orbit would likely be very old, cool and therefore dim — the scientists think the Webb telescope can still be used to find large Jupiter-sized planets in its orbit. The authors call Alpha Centauri "an exceptional but challenging target for exoplanet searches."
This early conclusion is based on just one set of observations from February 2025. Webb also observed Alpha Centauri A in August 2024 and April 2025, so more conclusions — and possibly a discovery of a planet — could be imminent.
Illustration of the Earth-like exoplanet Proxima Centauri b orbiting the star Proxima Centauri. ... More (Illustration by Tobias Roetsch/Future Publishing via Getty Images)
In 2016, astronomers found an exoplanet in Proxima Centauri's habitable zone and named it Proxima Centauri b. This exoplanet orbits its star every 11 days from just 5% of the Earth-sun distance from the star.
Proxima Centauri b is thought to orbit the star's 'habitable zone,' which is defined as a distance that allows temperatures to be warm enough for liquid water to pool on the planet's surface. However, it's thought that Proxima Centauri sometimes unleashes a massive stellar flare — an energetic explosion of high energy radiation — that would make life as we know it impossible on any planets in orbit.
A paper in 2020 suggested that Proxima Centauri may be orbited by a second "super-Earth" sized planet (bigger than Earth, but smaller than Uranus) about the same distance from its star as Mars is from the sun. If it exists, it orbits Proxima Centauri every 5.2 Earth years.
Barnard's star is one of the fastest-moving stars in the night sky because it's just six light-years from the solar system. In October 2024, scientists unveiled a planet around it thought to be about half the size of Venus. Called Barnard's b, it's around 20 times closer than Mercury is to the sun.
Wishing you clear skies and wide eyes.

Try Our AI Features

Explore what Daily8 AI can do for you:

Learn with AIFact CheckingText to SpeechAI Summary

Related Articles

Yahoo

14 hours ago

• Yahoo

Sunshine abounds as the summer solstice arrives

Peak sunshine has arrived in the Northern Hemisphere — the summer solstice. Friday is the longest day of the year north of the equator, where the solstice marks the start of astronomical summer. It's the opposite in the Southern Hemisphere, where it is the shortest day of the year and winter will start. The word 'solstice' comes from the Latin words 'sol' for sun and 'stitium' which can mean 'pause' or 'stop.' The solstice is the end of the sun's annual march higher in the sky, when it makes its longest, highest arc. The bad news for sun lovers: It then starts retreating and days will get a little shorter every day until late December. People have marked solstices for eons with celebrations and monuments, including Stonehenge, which was designed to align with the sun's paths at the solstices. But what is happening in the heavens? Here's what to know about the Earth's orbit. Solstices are when days and nights are at their most extreme As the Earth travels around the sun, it does so at an angle relative to the sun. For most of the year, the Earth's axis is tilted either toward or away from the sun. That means the sun's warmth and light fall unequally on the northern and southern halves of the planet. The solstices mark the times during the year when this tilt is at its most extreme, and days and nights are at their most unequal. During the Northern Hemisphere's summer solstice, the upper half of the earth is tilted toward the sun, creating the longest day and shortest night of the year. This solstice falls between June 20 and 22. Meanwhile, at the winter solstice, the Northern Hemisphere is leaning away from the sun — leading to the shortest day and longest night of the year. The winter solstice falls between December 20 and 23. The equinox is when there is an equal amount of day and night During the equinox, the Earth's axis and its orbit line up so that both hemispheres get an equal amount of sunlight. The word equinox comes from two Latin words meaning equal and night. That's because on the equinox, day and night last almost the same amount of time — though one may get a few extra minutes, depending on where you are on the planet. The Northern Hemisphere's spring — or vernal — equinox can land between March 19 and 21, depending on the year. Its fall – or autumnal — equinox can land between Sept. 21 and 24. On the equator, the sun will be directly overhead at noon. Equinoxes are the only time when both the north and south poles are lit by sunshine at the same time. What's the difference between meteorological and astronomical seasons? These are just two different ways to carve up the year. While astronomical seasons depend on how the Earth moves around the sun, meteorological seasons are defined by the weather. They break down the year into three-month seasons based on annual temperature cycles. By that calendar, spring starts on March 1, summer on June 1, fall on Sept. 1 and winter on Dec. 1. ___ The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute's Department of Science Education and the Robert Wood Johnson Foundation. The AP is solely responsible for all content.

Associated Press

19 hours ago

• Associated Press

Sunshine abounds as the summer solstice arrives

Peak sunshine has arrived in the Northern Hemisphere — the summer solstice. Friday is the longest day of the year north of the equator, where the solstice marks the start of astronomical summer. It's the opposite in the Southern Hemisphere, where it is the shortest day of the year and winter will start. The word 'solstice' comes from the Latin words 'sol' for sun and 'stitium' which can mean 'pause' or 'stop.' The solstice is the end of the sun's annual march higher in the sky, when it makes its longest, highest arc. The bad news for sun lovers: It then starts retreating and days will get a little shorter every day until late December. People have marked solstices for eons with celebrations and monuments, including Stonehenge, which was designed to align with the sun's paths at the solstices. But what is happening in the heavens? Here's what to know about the Earth's orbit. Solstices are when days and nights are at their most extreme As the Earth travels around the sun, it does so at an angle relative to the sun. For most of the year, the Earth's axis is tilted either toward or away from the sun. That means the sun's warmth and light fall unequally on the northern and southern halves of the planet. The solstices mark the times during the year when this tilt is at its most extreme, and days and nights are at their most unequal. During the Northern Hemisphere's summer solstice, the upper half of the earth is tilted toward the sun, creating the longest day and shortest night of the year. This solstice falls between June 20 and 22. Meanwhile, at the winter solstice, the Northern Hemisphere is leaning away from the sun — leading to the shortest day and longest night of the year. The winter solstice falls between December 20 and 23. The equinox is when there is an equal amount of day and night During the equinox, the Earth's axis and its orbit line up so that both hemispheres get an equal amount of sunlight. The word equinox comes from two Latin words meaning equal and night. That's because on the equinox, day and night last almost the same amount of time — though one may get a few extra minutes, depending on where you are on the planet. The Northern Hemisphere's spring — or vernal — equinox can land between March 19 and 21, depending on the year. Its fall – or autumnal — equinox can land between Sept. 21 and 24. On the equator, the sun will be directly overhead at noon. Equinoxes are the only time when both the north and south poles are lit by sunshine at the same time. What's the difference between meteorological and astronomical seasons? These are just two different ways to carve up the year. While astronomical seasons depend on how the Earth moves around the sun, meteorological seasons are defined by the weather. They break down the year into three-month seasons based on annual temperature cycles. By that calendar, spring starts on March 1, summer on June 1, fall on Sept. 1 and winter on Dec. 1. ___ The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute's Department of Science Education and the Robert Wood Johnson Foundation. The AP is solely responsible for all content.

Yahoo

a day ago

• Yahoo

NASA raises chance for asteroid to hit the moon

June 19 (UPI) -- NASA has announced that an asteroid about 200 feet in diameter is now slightly more likely to crash into the moon. According to the newest data collected, NASA's Center for Near-Earth Object Studies at the agency's Jet Propulsion Laboratory has refined the expected course for Asteroid 2024 YR4 and has given it an increased 4.3% probability of striking the moon on Dec. 22, 2032. The original likelihood was at 3.8% probability. The space rock is too far off in space to be detected with ground telescopes, but the James Webb Space Telescope, which orbits the sun, was able to take a new look at the space rock earlier this month before it was obscured from view. It was that opportunity that provided the data that led to the changed forecast. Due to YR4's solar orbit, NASA won't be able to view it again until it comes back around the sun in 2028. According to a research paper submitted to the American Astronomical Society journals and published Monday, should the asteroid hit the moon, it could cause a crater as large as around 3,200 feet and release 6.5 megatons of energy. As much as 220 million pounds of lunar material could be released by such an impact, and then as much as 10% of that ejecta could fall to Earth a few days later, so "meteorites are unlikely, though not impossible" according to the paper, but it would create an "eye-catching" meteor shower. However, any moon bits that do come toward the Earth also could increase the meteoroid impact exposure faced by satellites in near-Earth orbit for as long as a decade.