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Explore This Section Exoplanets Home Exoplanets Overview Exoplanets Facts Types of Exoplanets Stars What is the Universe Search for Life The Big Questions Are We Alone? Can We Find Life? The Habitable Zone Why We Search Target Star Catalog Discoveries Discoveries Dashboard How We Find and Characterize Missions People Exoplanet Catalog Immersive The Exoplaneteers Exoplanet Travel Bureau 5 Ways to Find a Planet Strange New Worlds Universe of Monsters Galaxy of Horrors News Stories Blog Resources Get Involved Glossary Eyes on Exoplanets Exoplanet Watch More Multimedia ExEP This artist’s concept pictures the planets orbiting Barnard’s Star, as seen from close to the surface of one of them. Image credit: International Gemini Observatory/NOIRLab/NSF/AURA/P. Marenfeld The Discovery
Four rocky planets much smaller than Earth orbit Barnard’s Star, the next closest to ours after the three-star Alpha Centauri system. Barnard’s is the nearest single star.
Key Facts
Barnard’s Star, six light-years away, is notorious among astronomers for a history of false planet detections. But with the help of high-precision technology, the latest discovery — a family of four — appears to be solidly confirmed. The tiny size of the planets is also remarkable: Capturing evidence of small worlds at great distance is a tall order, even using state-of-the-art instruments and observational techniques.
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Watching for wobbles in the light from a star is one of the leading methods for detecting exoplanets — planets orbiting other stars. This “radial velocity” technique tracks subtle shifts in the spectrum of starlight caused by the gravity of a planet pulling its star back and forth as the planet orbits. But tiny planets pose a major challenge: the smaller the planet, the smaller the pull. These four are each between about a fifth and a third as massive as Earth. Stars also are known to jitter and quake, creating background “noise” that potentially could swamp the comparatively quiet signals from smaller, orbiting worlds.
Astronomers measure the back-and-forth shifting of starlight in meters per second; in this case the radial velocity signals from all four planets amount to faint whispers — from 0.2 to 0.5 meters per second (a person walks at about 1 meter per second). But the noise from stellar activity is nearly 10 times larger at roughly 2 meters per second.
How to separate planet signals from stellar noise? The astronomers made detailed mathematical models of Barnard’s Star’s quakes and jitters, allowing them to recognize and remove those signals from the data collected from the star.
The new paper confirming the four tiny worlds — labeled b, c, d, and e — relies on data from MAROON-X, an “extreme precision” radial velocity instrument attached to the Gemini Telescope on the Maunakea mountaintop in Hawaii. It confirms the detection of the “b” planet, made with previous data from ESPRESSO, a radial velocity instrument attached to the Very Large Telescope in Chile. And the new work reveals three new sibling planets in the same system.
Fun Facts
These planets orbit their red-dwarf star much too closely to be habitable. The closest planet’s “year” lasts a little more than two days; for the farthest planet, it’s is just shy of seven days. That likely makes them too hot to support life. Yet their detection bodes well in the search for life beyond Earth. Scientists say small, rocky planets like ours are probably the best places to look for evidence of life as we know it. But so far they’ve been the most difficult to detect and characterize. High-precision radial velocity measurements, combined with more sharply focused techniques for extracting data, could open new windows into habitable, potentially life-bearing worlds.
Barnard’s star was discovered in 1916 by Edward Emerson Barnard, a pioneering astrophotographer.
The Discoverers
An international team of scientists led by Ritvik Basant of the University of Chicago published their paper on the discovery, “Four Sub-Earth Planets Orbiting Barnard’s Star from MAROON-X and ESPRESSO,” in the science journal, “The Astrophysical Journal Letters,” in March 2025. The planets were entered into the NASA Exoplanet Archive on March 13, 2025.
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Last Updated Apr 01, 2025 Related Terms
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Explore This Section Perseverance Home Mission Overview Rover Components Mars Rock Samples Where is Perseverance? Ingenuity Mars Helicopter Mission Updates Science Overview Objectives Instruments Highlights Exploration Goals News and Features Multimedia Perseverance Raw Images Images Videos Audio More Resources Mars Missions Mars Sample Return Mars Perseverance Rover Mars Curiosity Rover MAVEN Mars Reconnaissance Orbiter Mars Odyssey More Mars Missions Mars Home 3 min read
Visiting Mars on the Way to the Outer Solar System
Written by Roger Wiens, Principal Investigator, SuperCam instrument / Co-Investigator, SHERLOC instrument at Purdue University
A portion of the “Sally’s Cove” outcrop where the Perseverance rover has been exploring. The radiating lines in the rock on the left of the image may indicate that it is a shatter cone, showing the effects of the shock wave from a nearby large impact. The image was taken by Mastcam-Z’s left camera on March 21, 2025 (Sol 1452, or Martian day 1,452 of the Mars 2020 mission) at the local mean solar time of 12:13:44. Mastcam-Z is a pair of cameras located high on the rover’s mast. This image was voted by the public as “Image of the week.” NASA/JPL-Caltech/ASU Recently Mars has had a few Earthly visitors. On March 1, NASA’s Europa Clipper flew within 550 miles (884 kilometers) of the Red Planet’s surface on its way out to Jupiter. On March 12, the European Space Agency’s Hera spacecraft flew within about 3,100 miles (5,000 kilometers) of Mars, and only 300 kilometers from its moon, Deimos. Hera is on its way to study the binary asteroid Didymos and its moon Dimorphos. Next year, in May 2026, NASA’s Psyche mission is scheduled to buzz the Red Planet on its way to the metal-rich asteroid 16 Psyche, coming within a few thousand kilometers.
Why all these visits to Mars? You might at first think that they’re using Mars as an object of opportunity for their cameras, and you would be partially right. But Mars has more to give these missions than that. The main reason for these flybys is the extra speed that Mars’ velocity around the Sun can give them. The idea that visiting a planet can speed up a spacecraft is not all that obvious, because the same gravity that attracts the spacecraft on its way towards the planet will exert a backwards force as the spacecraft leaves the planet.
The key is in the direction that it approaches and leaves the planet. If the spacecraft leaves Mars heading in the direction that Mars is traveling around the Sun, it will gain speed in that direction, slingshotting it farther into the outer solar system. A spacecraft can typically gain several percent of its speed by performing such a slingshot flyby. The closer it gets to the planet, the bigger the effect. However, no mission wants to be slowed by the upper atmosphere, so several hundred kilometers is the closest that a mission should go. And the proximity to the planet is also affected by the exact direction the spacecraft needs to go when it leaves Mars.
Clipper’s Mars flyby was a slight exception, slowing down the craft — by about 1.2 miles per second (2 kilometers per second) — to steer it toward Earth for a second gravity assist in December 2026. That will push the spacecraft the rest of the way to Jupiter, for its 2030 arrival.
While observing Mars is not the main reason for their visits, many of the visiting spacecraft take the opportunity to use their cameras either to perform calibrations or to study the Red Planet and its moons.
During Clipper’s flyby over sols 1431-1432, Mastcam-Z was directed to watch the skies for signs of the interplanetary visitor. Clipper’s relatively large solar panels could have reflected enough sunlight for it to be seen in the Mars night sky, much as we can see satellites overhead from Earth. Unfortunately, the spacecraft entered the shadow of Mars just before it came into potential view above the horizon from Perseverance’s vantage point, so the sighting did not happen. But it was worth a try.
Meanwhile, back on the ground, Perseverance is performing something of a cliff-hanger. “Sally’s Cove” is a relatively steep rock outcrop in the outer portion of Jezero crater’s rim just north of “Broom Hill.” Perseverance made an approach during March 19-23, and has been exploring some dark-colored rocks along this outcrop, leaving the spherules behind for the moment. Who knows what Perseverance will find next?
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Last Updated Mar 28, 2025 Related Terms
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By NASA
Explore Hubble Hubble Home Overview About Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & Benefits Hubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts Science Hubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered Explore the Night Sky Observatory Hubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb Team Hubble Team Career Aspirations Hubble Astronauts News Hubble News Hubble News Archive Social Media Media Resources Multimedia Multimedia Images Videos Sonifications Podcasts e-Books Online Activities Lithographs Fact Sheets Posters Hubble on the NASA App Glossary More 35th Anniversary Online Activities 2 min read
Hubble Captures a Neighbor’s Colorful Clouds
This NASA/ESA Hubble Space Telescope image features part of the Small Magellanic Cloud. ESA/Hubble & NASA, C. Murray
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Say hello to one of the Milky Way’s neighbors! This NASA/ESA Hubble Space Telescope image features a scene from one of the closest galaxies to the Milky Way, the Small Magellanic Cloud (SMC). The SMC is a dwarf galaxy located about 200,000 light-years away. Most of the galaxy resides in the constellation Tucana, but a small section crosses over into the neighboring constellation Hydrus.
Thanks to its proximity, the SMC is one of only a few galaxies that are visible from Earth without the help of a telescope or binoculars. For viewers in the southern hemisphere and some latitudes in the northern hemisphere, the SMC resembles a piece of the Milky Way that has broken off, though in reality it’s much farther away than any part of our own galaxy.
With its 2.4-meter mirror and sensitive instruments, Hubble’s view of the SMC is far more detailed and vivid than what humans can see. Researchers used Hubble’s Wide Field Camera 3 to observe this scene through four different filters. Each filter permits different wavelengths of light, creating a multicolored view of dust clouds drifting across a field of stars. Hubble’s view, however, is much more zoomed-in than our eyes, allowing it to observe very distant objects. This image captures a small region of the SMC near the center of NGC 346, a star cluster that is home to dozens of massive young stars.
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Claire Andreoli (claire.andreoli@nasa.gov)
NASA’s Goddard Space Flight Center, Greenbelt, MD
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Last Updated Mar 21, 2025 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
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ESA/Hubble & NASA, R. Sankrit In this NASA/ESA Hubble Space Telescope image, Hubble once again lifts the veil on a famous — and frequently photographed — supernova remnant: the Veil Nebula. The remnant of a star roughly 20 times as massive as the Sun that exploded about 10,000 years ago, the Veil Nebula is situated about 2,400 light-years away in the constellation Cygnus. Hubble images of this photogenic nebula were first taken in 1994 and 1997, and again in 2015.
This view combines images taken in three different filters by Hubble’s Wide Field Camera 3, highlighting emission from hydrogen, sulfur, and oxygen atoms. The image shows just a small fraction of the Veil Nebula; if you could see the entire nebula without the aid of a telescope, it would be as wide as six full Moons placed side-by-side.
Although this image captures the Veil Nebula at a single point in time, it helps researchers understand how the supernova remnant evolves over decades. Combining this snapshot with Hubble observations from 1994 will reveal the motion of individual knots and filaments of gas over that span of time, enhancing our understanding of this stunning nebula.
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Explore Hubble Hubble Home Overview About Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & Benefits Hubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts Science Hubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered Explore the Night Sky Observatory Hubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb Team Hubble Team Career Aspirations Hubble Astronauts News Hubble News Hubble News Archive Social Media Media Resources Multimedia Multimedia Images Videos Sonifications Podcasts e-Books Online Activities Lithographs Fact Sheets Posters Hubble on the NASA App Glossary More 35th Anniversary Online Activities 1 min read
Hubble Captures New View of Colorful Veil
This NASA/ESA Hubble Space Telescope image a supernova remnant called the Veil Nebula. ESA/Hubble & NASA, R. Sankrit
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In this NASA/ESA Hubble Space Telescope image, Hubble once again lifts the veil on a famous — and frequently photographed — supernova remnant: the Veil Nebula. The remnant of a star roughly 20 times as massive as the Sun that exploded about 10,000 years ago, the Veil Nebula is situated about 2,400 light-years away in the constellation Cygnus. Hubble images of this photogenic nebula were first taken in 1994 and 1997, and again in 2015.
This view combines images taken in three different filters by Hubble’s Wide Field Camera 3, highlighting emission from hydrogen, sulfur, and oxygen atoms. The image shows just a small fraction of the Veil Nebula; if you could see the entire nebula without the aid of a telescope, it would be as wide as six full Moons placed side-by-side.
Although this image captures the Veil Nebula at a single point in time, it helps researchers understand how the supernova remnant evolves over decades. Combining this snapshot with Hubble observations from 1994 will reveal the motion of individual knots and filaments of gas over that span of time, enhancing our understanding of this stunning nebula.
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Media Contact:
Claire Andreoli (claire.andreoli@nasa.gov)
NASA’s Goddard Space Flight Center, Greenbelt, MD
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Last Updated Feb 28, 2025 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
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