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Another red dwarf was caught throwing an overpowering flare, reinforcing the idea that life might be struggling to take root around these dark little stars.
A new study reports that NASA's Hubble Space Telescope has detected the super-light emitted by a red dwarf called J02365, located about 130 light-years from Earth. The blast revealed about 10 ^ 32 ergs of energy in the extreme ultraviolet spectrum of the electromagnetic spectrum, making it more powerful than any of the eruptions recorded by our sun, said study members.
"When I realized the amount of light emitted by the superflare, I sat for a while staring at my computer screen by simply thinking" Whoa ", the main author of the Study, Parke Loyd, postdoctoral researcher at the School of Earth and Space Exploration at Arizona State University, said in a statement. [The Sun’s Wrath: Worst Solar Storms in History]
Loyd and his colleagues nicknamed this monster the "Hazflare", according to the name of the Hubble observing program that detected it. This program is HAZMAT, abbreviation for "Living Areas and Dwarves Activity M over Time".
HAZMAT studies red dwarfs, also called M dwarves, of three different ages: young (about 40 million years old), middle (about 650 million years old) and old (several billion years old) . The goal is to better understand the habitability of the planets that surround the red dwarfs.
This is a key issue for astrobiologists because red dwarfs harbor the largest number of real estate in the galaxy. About 75% of the stars in the Milky Way are dwarves, and many of them probably have planets in the "habitable zone" – the range of distances of a star that can support the existence of liquid water, and therefore life as we know it. In fact, the sun's closest star, the red dwarf Proxima Centauri, has a planet called Proxima b that seems to orbit in the habitable zone.
In addition, red dwarfs burn for billions of years, giving life a very long window to launch and diversify. (Sun-like stars, on the other hand, live only 10 billion years or so.)
The habitable zone is a controversial subject. Some researchers question the utility of focusing on surface waters, as our own solar system contains many worlds with potentially habitable buried oceans – for example, the Jupiter Moon Europa satellite and the satellite Saturn Enceladus.
And other scientists criticize the idea as too simplistic given the many variables involved in livability. For example, the classical definition does not take into account the planetary mass, which can have a significant impact on the scope and range of the habitable zone. Deeper worlds retain their internal heat longer and may also retain thicker atmospheres, which may contain more greenhouse gases that retain heat.
Observations with the Hubble Space Telescope revealed a superflare (red line) that caused a sudden increase in the brightness of a red dwarf star in the far ultraviolet by a factor of 200.
Credit: P. Loyd / ASU
And things get even more complicated with red dwarfs. Because these stars are so dark, their habitable areas are very close to each other – so close, in fact, that habitable planets such as Proxima b are probably locked, always showing the same face for their star, in the same way that the moon always shows its proximity. land side.
A world with a hot day and a freezing night might not be very friendly. Some research suggests that a red dwarf planet of the habitable zone can avoid this fate if it retains an atmosphere thick enough to carry and diffuse the heat of the day. But we face another complication: flares. Especially those incredibly powerful ones like the Hazflare.
The red dwarves are very active in their youth, emitting many such rockets. Astronomers have documented this activity many times; For example, we saw that Proxima Centauri was triggering a super-rocket in March 2016. Such eruptions can erase the atmosphere of habitable planets like Proxima b, which would make such worlds very unlikely, some scientists pointed out. [Proxima b: Closest Earth-Like Planet Discovery in Pictures]
But this is only a hypothesis at this stage, said Evgenya Shkolnik, principal investigator at HAZMAT, an assistant professor at the USS School of Earth and Space Exploration.
"I do not think we know for sure if the planets orbiting the red dwarfs are still habitable, but I think time will tell," said Shkolnik in the same statement. "It's great to live in a time when we have the technology to answer these kinds of questions, rather than just philosophizing about them."
The new study presents the results of the first phase of HAZMAT: observing the flare frequency of 12 red dwarfs aged 40 million years old. The data suggest that the eruptions of the youngest red dwarves are 100 to 1,000 times more powerful than the eruptions emitted by the former Dwarves, the researchers said.
Future observations from HAZMAT will further clarify the relationship between age and burning. The program will then study the middle-aged red dwarves and then turn to the old ones.
The new article has been accepted for publication in The Astrophysical Journal. You can read it for free at the arXiv.org online preprinting site.
Mike Wall's book on the quest for extraterrestrial life, "Out There," will be published on November 13 by Grand Central Publishing. Follow him on Twitter @michaeldwall. follow us @Spacedotcom or Facebook. Originally posted on Space.com.
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