Recently discovered planets not as safe from stellar flares as first thought

August 24, 2020

A nearby star, the host of two (and possibly three) planets, was initially thought to be quiet and boring. These attributes are sought-after as they create a safe environment for their planets, especially those that may be in what scientists call “the habitable zone” where liquid water could exist on their surfaces and life might be possible. But astronomers at Arizona State University have announced that this nearby star turns out to be not so tame after all.

This star, named GJ 887, is one of the brightest M stars in the sky. M stars are low-mass red stars that outnumber stars like our sun more than tenfold, and the vast majority of planets in our galaxy orbit them. 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). Credits: NASA, ESA and D. Player (STScI) Download Full Image

GJ 887 had initially been spotlighted for the apparently gentle space environment it provides to its recently discovered planets. In monitoring by NASA’s Transiting Exoplanet Survey Satellite (TESS), a mission to search for planets outside our solar system, the star oddly exhibited no detectable flares over 27 days of continuous observations.   

And an absence of flares is a quality that favors the survival of atmospheres on planets orbiting the star, and therefore potential life on those planets.

But ASU astronomers Parke Loyd and Evgenya Shkolnik of ASU’s School of Earth and Space Exploration had their doubts about GJ 887 being all that quiet. Digging into archival Hubble Space Telescope data, they found that GJ 887 actually flares hourly.

How did they spot this difference? By using far-ultraviolet light, Loyd, Shkolnik and their collaborators were able to see huge spikes in brightness caused by stellar flares.

Their findings were recently published in a Research Note of the American Astronomical Society, with co-authors from the University of Colorado, Boulder and the Naval Research Laboratory in Washington, D.C.

M stars: Hosts of most potentially habitable planets

Because there are so many of them, M stars like GJ 887 are a key player in humanity's quest to understand where Earth fits into the grand menagerie of planets in the universe and in the search for life on other planets.

“If the genesis of life on a planet is more a less a roll of the dice, then M stars are rolling those dice far more than any other type of star,” Loyd explained.

But there is a catch. M stars are prone to peppering their planets with flares. They can also be two-faced, appearing calm in visible light, like that observed by the TESS mission. In reality, they can be rife with flares that are clearly apparent in ultraviolet light, which has photons (particles of light) of much greater energy than visible light. And each flare has the potential to bombard the star's planets with a magnetic storm and a shower of fast-moving particles, increasing the chances that the atmospheres of GJ 887's planets were eroded away long ago.

“It is fascinating to know that observing stars in normal optical light (as the TESS mission does) doesn’t come close to telling the whole story,” said Shkolnik. “The damaging radiation environment of these planets can only fully be understood with ultraviolet observations, like those from the Hubble Space Telescope.”

While ultraviolet monitoring of M stars is valuable, the resources astronomers have to devote to such observations are currently limited. Luckily, there are plans in the works for missions that can help fill this need, including an ASU-led CubeSat mission called the Star-Planet Activity Research CubeSat (SPARCS), for which Shkolnik is the principal investigator. This mission will provide astronomers with the observing time they need to capture ultraviolet flares from M stars and measure how often they happen, ultimately leading to a greater understanding of the stars and planets in our galaxy.

“A star’s ultraviolet emission is really a critical, albeit still missing, puzzle piece to our understanding of planet atmospheres and their habitability,” Shkolnik said. 

Karin Valentine

Media Relations & Marketing manager, School of Earth and Space Exploration


Research shows water quality could diminish in closed buildings during COVID-19 pandemic

ASU researcher joins study to understand how extended shutdowns affect water quality in buildings

August 24, 2020

While bars, gyms, dine-in restaurants and other buildings have been closed to help prevent the spread of COVID-19, water left sitting in pipes could change in quality.

It’s possible that water left sitting for long periods of time could contain excessive amounts of heavy metals and pathogens concentrated in pipes nationwide, say researchers who have begun a field study on the impact of a pandemic shutdown on buildings. photo of buildings from an empty street Many buildings around the country are closed indefinitely to prevent the spread of COVID-19, but water left sitting in pipes could change in quality. The Arizona heat could exacerbate stagnation problems. Photo courtesy Shutterstock Download Full Image

“There are several factors that encourage the growth of disease-causing microorganisms in buildings — low or nonexistent disinfectant residual, such as chloramine or chlorine, poor temperature control and water stagnation inside water pipes,” said Kerry Hamilton, a researcher with the Arizona State University Biodesign Center for Environmental Health Engineering. Hamilton has expertise in risk assessment for pathogenic microorganisms, specifically for the bacteria that causes Legionnaires' disease commonly linked to poor water quality in buildings.

Hamilton is a co-author of a new report completed with Purdue University and funded by the National Science Foundation’s Rapid Response Research program. The study involves monitoring water quality in buildings both during a period of extended vacancy and when occupants have returned.

Her contribution to the study focused on summarizing practices used to notify building occupants of potential water quality issues and what communication typically takes place between utilities, building owners or facilities managers, health departments and building occupants.

“This may be an issue when high ambient temperatures can encourage the growth of undesirable microorganisms in water systems in buildings,” said Hamilton, an assistant professor with the School of Sustainable Engineering and the Built Environment.

“Shutdowns due to COVID-19 can exacerbate stagnation problems and point to the need for utilities, facilities managers and the general public to be especially aware of these issues and to take action to prevent disease from exposure to water that has been allowed to remain stagnant in pipes.”

“We don’t design buildings to be shut down for months. This study focuses on the consequences and could help building owners make sure that their buildings are safe and operational when occupants return,” said Andrew Whelton, a Purdue associate professor of civil engineering and environmental and ecological engineering and lead investigator.

Whelton’s field study is part of a national effort to advise public health officials, building owners and water utilities on how to safely recommission buildings with low or no occupancy due to the pandemic.

Whelton and other researchers across the U.S. have begun drafting recommendations compiled by this effort in a study published June 16 by the American Water Works Association journal "Water Science." Collaborators on this study include experts from leading plumbing safety scientists and engineers from ASU, Purdue, Virginia Tech, Legionella Risk Management, Inc., University of Memphis, University of Iowa, Northeastern University and Polytechnique Montréal in Canada. The recommendations are based on implications from other studies of water stagnation in large buildings.

Typically, buildings can prevent stagnation through regular water use. This brings in new water with disinfectant. But extended building shutdowns will require different solutions, the researchers said. The Centers for Disease Control provides guidelines for the reopening of buildings after shutdowns.

Sandra Leander

Assistant Director of Media Relations, ASU Knowledge Enterprise