Superflares From Young Red Dwarf Stars Imperil Planets

Violent outbursts of seething gas from young red dwarf stars may make conditions uninhabitable on fledgling planets. In this artist’s rendering, an active, young red dwarf (right) is stripping the atmosphere from an orbiting planet (left). Scientists found that flares from the youngest red dwarfs they surveyed — approximately 40 million years old — are 100 to 1,000 times more energetic than when the stars are older. They also detected one of the most intense stellar flares ever observed in ultraviolet light — more energetic than the most powerful flare ever recorded from our Sun. Credits: NASA, ESA and D. Player (STScI)

The word “HAZMAT” describes substances that pose a risk to the environment, or even to life itself. Imagine the term being applied to entire planets, where violent flares from the host star may make worlds uninhabitable by affecting their atmospheres.

NASA’s Hubble Space Telescope is observing such stars through a large program called HAZMAT — Habitable Zones and M dwarf Activity across Time.

“M dwarf” is the astronomical term for a red dwarf star — the smallest, most abundant and longest-lived type of star in our galaxy. The HAZMAT program is an ultraviolet survey of red dwarfs at three different ages: young, intermediate, and old.

Stellar flares from red dwarfs are particularly bright in ultraviolet wavelengths, compared with Sun-like stars. Hubble’s ultraviolet sensitivity makes the telescope very valuable for observing these flares. The flares are believed to be powered by intense magnetic fields that get tangled by the roiling motions of the stellar atmosphere. When the tangling gets too intense, the fields break and reconnect, unleashing tremendous amounts of energy.

The team has found that the flares from the youngest red dwarfs they surveyed — just about 40 million years old — are 100 to 1,000 times more energetic than when the stars are older. This younger age is when terrestrial planets are forming around their stars.

Approximately three-quarters of the stars in our galaxy are red dwarfs. Most of the galaxy’s “habitable-zone” planets — planets orbiting their stars at a distance where temperatures are moderate enough for liquid water to exist on their surface — likely orbit red dwarfs. In fact, the nearest star to our Sun, a red dwarf named Proxima Centauri, has an Earth-size planet in its habitable zone.

However, young red dwarfs are active stars, producing ultraviolet flares that blast out so much energy that they could influence atmospheric chemistry and possibly strip off the atmospheres of these fledgling planets.

“The goal of the HAZMAT program is to help understand the habitability of planets around low-mass stars,” explained Arizona State University’s Evgenya Shkolnik, the program’s principal investigator. “These low-mass stars are critically important in understanding planetary atmospheres.”

The results of the first part of this Hubble program are being published in The Astrophysical Journal. This study examines the flare frequency of 12 young red dwarfs. “Getting these data on the young stars has been especially important, because the difference in their flare activity is quite large as compared to older stars,” said Arizona State University’s Parke Loyd, the first author on this paper.

The observing program detected one of the most intense stellar flares ever observed in ultraviolet light. Dubbed the “Hazflare,” this event was more energetic than the most powerful flare from our Sun ever recorded.

“With the Sun, we have a hundred years of good observations,” Loyd said. “And in that time, we’ve seen one, maybe two, flares that have an energy approaching that of the Hazflare. In a little less than a day’s worth of Hubble observations of these young stars, we caught the Hazflare, which means that we’re looking at superflares happening every day or even a few times a day.”

Could super-flares of such frequency and intensity bathe young planets in so much ultraviolet radiation that they forever doom chances of habitability? According to Loyd, “Flares like we observed have the capacity to strip away the atmosphere from a planet. But that doesn’t necessarily mean doom and gloom for life on the planet. It just might be different life than we imagine. Or there might be other processes that could replenish the atmosphere of the planet. It’s certainly a harsh environment, but I would hesitate to say that it is a sterile environment.”

The next part of the HAZMAT study will be to study intermediate-aged red dwarfs that are 650 million years old. Then the oldest red dwarfs will be analyzed and compared with the young and intermediate stars to understand the evolution of the ultraviolet radiation environment of low-mass planets around these low-mass stars. The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, in Washington, D.C.

Ann Jenkins / Ray Villard
Space Telescope Science Institute, Baltimore, Maryland
410-338-4488 / 410-338-4514
jenkins@stsci.edu / villard@stsci.edu

Evgenya Shkolnik
Arizona State University, Tempe, Arizona 808-292-9088
shkolnik@asu.edu

Parke Loyd
Arizona State University, Tempe, Arizona
parke@asu.edu

Editor: Karl Hille

Source: NASA/Hubble

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Make Sure You Observe the Moon on October 20

On Saturday, October 20, NASA will host the ninth annual International Observe the Moon Night. One day each year, everyone on Earth is invited to observe and learn about the Moon together, and to celebrate the cultural and personal connections we all have with our nearest celestial neighbor.

There are a number of ways to celebrate. You can attend an event, host your own, or just look up! Here are 10 of our favorite ways to observe the Moon:

1. Look up

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Image credit: NASA’s Scientific Visualization Studio/Ernie Wright

The simplest way to observe the Moon is simply to look up. The Moon is the brightest object in our night sky, the second brightest in our daytime sky and can be seen from all around the world — from the remote and dark Atacama Desert in Chile to the brightly lit streets of Tokyo. On October 20, the near side of the Moon, or the side facing Earth, will be about 80 percent illuminated, rising in the early evening.

See the Moon phase on October 20 or any other day of the year!

2. Peer through a telescope or binoculars

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The Moon and Venus are great targets for binoculars. Image Credit: NASA/Bill Dunford

With some magnification help, you will be able to focus in on specific features on the Moon, like the Sea of Tranquility or the bright Copernicus Crater. Download our Moon maps for some guided observing on Saturday.

3. Photograph the Moon

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Image credit: NASA/GSFC/ASU

Our Lunar Reconnaissance Orbiter (LRO) has taken more than 20 million images of the Moon, mapping it in stunning detail. You can see featured, captioned images on LRO’s camera website, like the one of Montes Carpatus seen here. And, of course, you can take your own photos from Earth. Check out our tips on photographing the Moon!

4. Take a virtual field trip

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Image credit: NASA/JPL-Caltech

Plan a lunar hike with Moontrek. Moontrek is an interactive Moon map made using NASA data from our lunar spacecraft. Fly anywhere you’d like on the Moon, calculate the distance or the elevation of a mountain to plan your lunar hike, or layer attributes of the lunar surface and temperature. If you have a virtual reality headset, you can experience Moontrek in 3D.

5. Touch the topography

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Image credit: NASA GSFC/Jacob Richardson

Observe the Moon through touch! If you have access to a 3D printer, you can peruse our library of 3D models and lunar landscapes. This model of the Apollo 11 landing site created by NASA scientist Jacob Richardson, is derived from LRO’s topographic data. Near the center, you can actually feel a tiny dot where astronauts Neil Armstrong and Buzz Aldrin left the Lunar Descent Module.

6. Make Moon art

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Image credit: LPI/Andy Shaner

Enjoy artwork of the Moon and create your own! For messy fun, lunar crater paintings demonstrate how the lunar surface changes due to consistent meteorite impacts.

7. Relax on your couch

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Image credit: NASA’s Scientific Visualization Studio/Ernie Wright

There are many movies that feature our nearest neighbor, from A Voyage to the Moon by George Melies, to Apollo 13, to the newly released First Man. You can also spend your evening with our lunar playlist on YouTube or this video gallery, learning about the Moon’s role in eclipses, looking at the Moon phases from the far side, and seeing the latest science portrayed in super high resolution. You’ll impress all of your friends with your knowledge of supermoons.

8. Listen to the Moon

Video credit: NASA’s Scientific Visualization Studio/Ernie Wright

Make a playlist of Moon songs. For inspiration, check out this list of lunar tunes. We also recommend LRO’s official music video, The Moon and More, featuring Javier Colon, season 1 winner of NBC’s “The Voice.” Or you can just watch this video featuring “Clair de Lune,” by French composer Claude Debussy, over and over.

9. See the Moon through the eyes of a spacecraft

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Image credit: NASA/GSFC/MIT

Visible light is just one tool that we use to explore our universe. Our spacecraft contain many different types of instruments to analyze the Moon’s composition and environment. Review the Moon’s gravity field with data from the GRAIL spacecraft or decipher the maze of this slope map from the laser altimeter onboard LRO. This collection from LRO features images of the Moon’s temperature and topography. You can learn more about our different missions to explore the Moon here.

10. Continue your observations throughout the year

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Image credit: NASA’s Scientific Visualization Studio/Ernie Wright

An important part of observing the Moon is to see how it changes over time. International Observe the Moon Night is the perfect time to start a Moon journal. See how the shape of the Moon changes over the course of a month, and keep track of where and what time it rises and sets. Observe the Moon all year long with these tools and techniques!

However you choose to celebrate International Observe the Moon Night, we want to hear about it! Register your participation and share your experiences on social media with #ObserveTheMoon or on our Facebook page. Happy observing!

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