Space News & Blog Articles

There’s something menacing about red dwarfs. Human eyes are accustomed to our benevolent yellow Sun and the warm light it shines on our glorious, life-covered planet. But red dwarfs can seem moody, ill-tempered, and even foreboding.

For long periods of time, they can be calm, but then they can flare violently, flashing a warning to any life that might be gaining a foothold on a nearby planet.

Red dwarfs (M dwarfs) are the most common type of star in the Milky Way. This means that most exoplanets orbit red dwarfs, not nice, well-behaved G-type stars like our Sun. As astronomers study red dwarfs in greater detail, they’ve found that red dwarfs might not be the best stellar hosts when it comes to exoplanet habitability. Multiple studies have shown that red dwarfs can flare violently, emitting enough powerful radiation to render nearby planets uninhabitable, even when they’re firmly in the potentially habitable zone.

But there’s still a lot astronomers don’t know about red dwarfs and their wild nature. A new study examined 177 M-dwarfs to better understand their long-term variability. The researchers found that red dwarf behaviour is more complex than thought, and even the calmest red dwarfs are wilder than the Sun.

The study is titled “Characterisation of stellar activity of M dwarfs. I. Long-timescale variability in a large sample and detection of new cycles.” The paper will be published in the journal Astronomy and Astrophysics. The lead author is Lucile Mignon, a post-doctoral researcher from the University Grenoble Alpes and the French National Centre for Scientific Research (CNRS.)

Planetary exploration, specifically within our own Solar System, has provided a lifetime of scientific knowledge about the many worlds beyond Earth. However, this exploration, thus far, has primarily been limited to orbiters and landers/rovers designed for surface exploration of the celestial bodies they visit. But what if we could explore subsurface environments just as easily as we’ve been able to explore the surface, and could some of these subsurface dwellings not only shelter future astronauts, but host life, as well?

These are questions that a team of researchers at the University of Arizona (UArizona) hope to answer as they examine new technologies that could potentially aid both human and robotic exploration of planetary subsurface environments, including lava tubes, lava caves, and even subsurface oceans. This research comes at a particularly unique time with the NASA Artemis missions preparing to send humans back to the Moon in 2025, then hopefully to Mars, someday.

“Lava tubes and caves would make perfect habitats for astronauts because you don’t have to build a structure; you are shielded from harmful cosmic radiation, so all you need to do is make it pretty and cozy,” said Dr. Wolfgang Fink, who is an associate professor of electrical and computer engineering at UArizona, and lead author of the study.

For the study, the researchers introduced a dynamically deployed communication network (DDCN) that wirelessly connects robot explorers through a mesh topology network which not only lets each robot explorer work autonomously, but also as a team, as the network grants them unfettered communication with each other. This type of system is essential since the geological structure being explored might not be able to relay radio signal commands from astronauts on the outside to the robot explorers on the inside, so an autonomous system could be the best option to achieve mission success. The researchers refer to the DDCN as “a Hansel & Gretel-inspired breadcrumb style” communication network based on the how the system is used.

“If you remember the book, you know how Hansel and Gretel dropped breadcrumbs to make sure they’d find their way back,” explained Dr. Fink, who is also the founder and director of the Visual and Autonomous Exploration Systems Research Laboratory at Caltech and UArizona. “In our scenario, the ‘breadcrumbs’ are miniaturized sensors that piggyback on the rovers, which deploy the sensors as they traverse a cave or other subsurface environment.”

Hubble Space Telescope’s Deep Field revealed thousands of galaxies in a seemingly empty spot in the sky. Now, the James Webb Space Telescope has taken deep field observations to the next level with its COSMOS-Web survey, revealing 25,000 galaxies in just six pictures, the first from this new survey.  

“It’s incredibly exciting to get the first data from the telescope for COSMOS-Web,” said principal investigator Jeyhan Kartaltepe, from the Rochester Institute of Technology’s School of Physics and Astronomy, in press release. “Everything worked beautifully and the data are even better than we expected. We’ve been working really hard to produce science quality images to use for our analysis and this is just a drop in the bucket of what’s to come.”

Indeed, the first images to be released from the survey accounts for just 4% of the data that will eventually be collected with COSMOS-Web. The images show many types of galaxies, including spiral galaxies, examples of gravitational lensing, and evidence of galaxy mergers. The only objects in the above image that are individual stars are the ones with JWST’s signature diffraction spikes. The rest are galaxies.

COSMOS-Web is the largest program in JWST’s first year and the goal of the survey is to map the earliest structures of the universe, as well as create a deep survey of up to 1 million galaxies. With a total of 255 hours of observing time, COSMOS-Web will map 0.6 square degrees of the sky with NIRCam, roughly the size of three full moons, and 0.2 square degrees with MIRI.

The image above is a mosaic of images taken in early January by JWST’s Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI). The survey will It will gather additional data in another 77 pointings  of the telescope in April and May and then a remaining 69 in December and January 2024.