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NASA’s Kepler spacecraft has discovered most of the confirmed exoplanets that we know of. But its successor, TESS (Transiting Exoplanet Survey Satellite), is catching up. New research announces the validation of eight more TESS candidates, and they’re all Super-Earths.

TESS’s planet-hunting mission has a more refined goal than its predecessor, Kepler. TESS was specifically built to detect exoplanets transiting in front of bright stars in Earth’s neighbourhood. It’s found about 400 confirmed exoplanets, but there’s a list of exoplanets awaiting confirmation that contains almost 6,000 candidates. There are only two ways to confirm all these exoplanets-in-waiting: further observations and statistical methods.

What all those unconfirmed candidates amount to is data. They’re hiding in TESS’s data, waiting for clever scientists to validate them. Further observations can help uncover them, but not alone.

The Validation of Transiting Exoplanets using Statistical Tools (VaTEST) project uses statistical tools and machine learning to comb through all of TESS’s data, looking for elusive exoplanets. In the VaTEST project, scientists are not only able to confirm planets while working around false positives; they’re also able to characterize exoplanet atmospheres suitable for further study.

A team of scientists presented their results in a paper titled “VaTEST III: Validation of 8 Potential Super-Earths from TESS Data.” Their paper is under review at the Publications of the Astronomical Society of Australia and is currently under pre-print. The lead author is Priyashkumar Mistry, a Ph.D. student at the University of New South Wales, Australia.

False positives are a persistent problem in exoplanet science. When you think about it, it’s easy to see why. TESS is looking for tiny dips in starlight around distant stars caused by an exoplanet passing in front of the stars. One blip isn’t enough; we need several, and there has to be a rhythm to them. But other things can give false impressions of a transiting planet, for example, eclipsing binary stars. Even a star’s natural variability can cloud the signals.

So TESS has gathered an enormous amount of data that has to be worked through, sorting out false positives from real signals, and that’s what VaTEST does. In this paper, the team has validated eight more Super-Earths.

“We have validated eight potential super-Earths using a combination of ground-based telescope data, high-resolution imaging, and the statistical validation tool known as TRICERATOPS,” the authors write.

PlanetEarth MassesEarth RadiiTOI-238b3.61.6TOI-771b2.81.4TOI-871b3.81.6TOI-1467b4.41.8TOI-1739b41.7TOI-2068b4.41.8TOI-4559b2.71.4TOI5799b3.71.6

Not only did they find eight more super-Earths, but they’ve identified six of them that are excellent candidates for additional study. “Among all these validated planets, six of them fall within the region known as’ keystone planets,’ which makes them particularly interesting for study,” they explain.

A keystone planet is an idea that has its roots in biology. In biology, a keystone species is one that defines an entire ecosystem. A great example is coral in coral reefs. Coral reefs are a distinct ecosystem anchored by coral.

In exoplanet science, a keystone planet is a planet that helps explain the overall population of exoplanets. In particular, it helps explain the radius gap we see in exoplanet populations. There’s a scarcity of planets between 1.5 and 2 Earth radii. It’s probably caused by photoevaporation mass loss. A star’s powerful radiation, especially in X-ray and UV emissions (XUV), can strip away a planet’s atmosphere over time, possibly creating a dearth of 1.5 to 2 Earth radii planets.

“It is noteworthy that planets within the size range investigated herein are absent from our own solar system, making their study crucial for gaining insights into the evolutionary stages between Earth and Neptune,” the authors explain. “These keystone planets play a pivotal role in advancing our understanding of the radius-valley phenomenon around low-mass stars.”

A histogram of planets with given radii from a sample of 900 Kepler systems. The decreased occurrence rate between 1.5 and 2.0 Earth radii is apparent. It's called the radius gap, Neptune desert, and the Fulton gap. Six of the new planets sit in this gap. Image Credit: Fulton et al. 2017
A histogram of planets with given radii from a sample of 900 Kepler systems. The decreased occurrence rate between 1.5 and 2.0 Earth
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5 Reasons You Must Backpack Idaho’s Sawtooth Mountains

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By Michael Lanza

Chances are that, by now, you’ve heard of Idaho’s Sawtooths—having typed that name into a search box may be the reason you’ve landed on this story. Maybe you’ve been intrigued at what you’ve heard or images you’ve seen from Idaho’s best-known mountain range. Perhaps you’ve even been there and the experience has only amplified your curiosity to see more of this range.

As someone who’s had the good fortune of having backpacked all over the country and in many other countries over the past three-plus decades, including the 10 years I spent as a field editor for Backpacker magazine and even longer running this blog, I rank the Sawtooths among the 10 best backpacking trips in America.

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Hi, I’m Michael Lanza, creator of The Big Outside. Click here to sign up for my FREE email newsletter. Join The Big Outside to get full access to all of my blog’s stories. Click here for my e-books to classic backpacking trips. Click here to learn how I can help you plan your next trip.

Backpackers on Trail 154 to Cramer Divide in Idaho’s Sawtooths.
” data-image-caption=”Backpackers on Trail 154 to Cramer Divide in Idaho’s Sawtooths.
” data-medium-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2021/04/06230304/Saw19-024-Backpackers-on-Trail-154-to-Cramer-Divide-Sawtooth-Mountains-Idaho.jpg?fit=200%2C300&ssl=1″ data-large-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2021/04/06230304/Saw19-024-Backpackers-on-Trail-154-to-Cramer-Divide-Sawtooth-Mountains-Idaho.jpg?fit=683%2C1024&ssl=1″ src=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2021/04/06230304/Saw19-024-Backpackers-on-Trail-154-to-Cramer-Divide-Sawtooth-Mountains-Idaho-683×1024.jpg?resize=683%2C1024&ssl=1″ alt=”Backpackers on Trail 154 to Cramer Divide in Idaho’s Sawtooths.” class=”wp-image-45355″ style=”width:572px;height:auto” srcset=”https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2021/04/06230304/Saw19-024-Backpackers-on-Trail-154-to-Cramer-Divide-Sawtooth-Mountains-Idaho.jpg 683w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2021/04/06230304/Saw19-024-Backpackers-on-Trail-154-to-Cramer-Divide-Sawtooth-Mountains-Idaho.jpg 200w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2021/04/06230304/Saw19-024-Backpackers-on-Trail-154-to-Cramer-Divide-Sawtooth-Mountains-Idaho.jpg 768w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2021/04/06230304/Saw19-024-Backpackers-on-Trail-154-to-Cramer-Divide-Sawtooth-Mountains-Idaho.jpg 800w” sizes=”(max-width: 683px) 100vw, 683px” data-recalc-dims=”1″ />Backpackers on Trail 154 to Cramer Divide in Idaho’s Sawtooths.

I’ve wandered around the Sawtooths at least a couple dozen times over more than two decades, including numerous backpacking trips, dayhikes, peak scrambles, rock climbing, and backcountry skiing. While there remain peaks on my list to climb, a few trails to hike, and many lakes to leap into (or just sit beside), the Sawtooths have become my backyard mountains. I feel at home there.

This story presents the five reasons I think every backpacker should take a multi-day hike through the Sawtooths—spotlighting the characteristics of a trip there that make this place unique. I believe this argument may persuade you to go (if, somehow, the photos don’t do it).

See my e-book “The Best Backpacking Trip in Idaho’s Sawtooth Mountains” to learn all you need to know to plan and pull off a five-day, 36-mile Sawtooths hike through the core of the Sawtooths, and my Custom Trip Planning page to learn how I can help you plan every detail of a multi-day hike there.

Please share your thoughts or experiences there in the comments section at the bottom of this story. I
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The Venerable Hubble Space Telescope Keeps Delivering

NGC 4753 dust lanes zoom 1024x469 1

The world was much different in 1990 when NASA astronauts removed the Hubble Space Telescope from Space Shuttle Discovery’s cargo bay and placed it into orbit. The Cold War was ending, there were only 5.3 billion humans, and the World Wide Web had just come online.

Now, the old Soviet Union is gone, replaced by a smaller but no less militaristic Russia. The human population has ballooned to 8.1 billion. The internet is a fixture in daily life. We also have a new, more powerful space telescope, the JWST.

But the Hubble keeps delivering, as this latest image shows.

The lenticular galaxy NGC 4753 is about 60 million light-years away. Lenticular galaxies are midway between elliptical and spiral galaxies. They have large-scale disks but only poorly defined spiral arms. NGC 4753 sees very little star formation because like other lenticulars, it’s used up most of its gas. The fact that they contain mostly older stars makes them similar to elliptical galaxies.

Among lenticulars, NGC 4753 is known for the dust lanes surrounding its nucleus. Astronomers think that spirals evolve into lenticulars in dense environments because they interact with other galaxies and with the intergalactic medium. However, NGC 4753 is in a low-density environment. Its environment and complex structure make it a target for astronomers to test their theories of galaxy formation and evolution.

This Hubble image is the sharpest ever taken of NGC 4753, revealing its intriguing complexity and highlighting the space telescope’s impressive resolving power.

Astronomers think that NGC 4753 is the result of a merger with a dwarf galaxy over one billion years ago. The dwarf galaxy was gas-rich, and NGC 4753's distinct dust rings probably accreted from the merger. NGC 4753's powerful gravity then shaped the gas into the complex shapes we see in this image. Image Credit: ESA/Hubble & NASA, L. Kelsey
Astronomers think that NGC 4753 is the result of a merger with a dwarf galaxy over one billion years ago. The dwarf galaxy was gas-rich, and NGC 4753’s distinct dust rings probably accreted from the merger. NGC 4753’s powerful gravity then shaped the gas into the complex shapes we see in this image. Image Credit: ESA/Hubble & NASA, L. Kelsey

NGC 4763’s unique structure results from a merger with a dwarf galaxy about 1.3 billion years ago. The video below from NOIRlab explains what happened.

NGC 4753 also hosts two known Type 1a supernovae, which are important because they help astronomers study the expansion of the Universe. They serve as standard candles, an important rung in the cosmic distance ladder.

Galaxies like NGC 4753 may not be rare, but the viewing angle plays a key role in identifying them. Our edge-on view of the galaxy makes its lenticular form clear. We could be seeing others like it from different angles that obscure its nature.

This is a model of NGC 4753, as seen from various viewing orientations. From left to right and top to bottom, the angle of the line of sight to the galaxy's equatorial plane ranges from 10° to 90° in steps of 10°. Although galaxies similar to NGC 4753 may not be rare, only certain viewing orientations allow for easy identification of a highly twisted disk. This infographic is a recreation of Figure 7 from a 1992 research paper.
This is a model of NGC
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Juno Reveals Secrets About Europa’s Icy Surface

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Europa has always held a fascination to me. I think it’s the concept of a world with a sub-surface ocean and the possibility of life that has inspired me and many others. In September 2022, NASAs Juno spacecraft made a flyby, coming within 355 kilometres of the surface. Since the encounter, scientists have been exploring the images and have identified regions where brine may have bubbled to the surface. Other images revealed possible, previously unidentified steep-walled depressions up to 50km wide, this could be caused by a free-floating ocean! 

Juno was launched to Jupiter on 5 August 2011. It took off from the Cape Canaveral site on board an Atlas V rocket and travelled around 3 billion kilometres. It arrived at Jupiter on 4 July 2016 and in September 2022 made its closest flyby of Europa. The frozen world is the second of the four Galilean satellites that were discovered by Galileo over 400 years ago. Visible in small telescopes, the true nature of the moon is only detectable by visiting craft like Juno. 

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Artist’s impression of NASA’s Galileo space probe in orbit of Jupiter. Credit: NASA

During its close fly-by, one of the onboard cameras known as Juno-Cam took the highest resolution images of the moon since Galileo took a flyby in 2000. The images supported the long held theory that the icy crusts at the north and south poles are not where they used to be. Another instrument on board, known as the Stellar Reference Unit (SRU), revealed possible activity resembling plumes where brine may have bubbled to the surface.

The ground track over Europa that was followed by Juno enabled imaging around the equatorial regions. The images revealed the usual, expected blocks of ice, walls, ridges and scarps but also found something else. Steep walled depressions that measured 20 to 50 kilometres across were also seen and they resembled large ovoid pits. 

Solar panels
One of Juno’s enormous solar panels, unfurled on Earth. NASA/JPL. SWrI

The observations of the meanderings of the north/south polar ice and the varied surface features all point towards an outer icy shell that is free-floating upon the sub surface ocean. This can only happen if the outer shell is not connected to the rocky interior. When this happens, there are high levels of stress on the ice which then causes the fracture pattern witnessed. The images represent the first time such patterns have been seen in the southern hemisphere, the first evidence of true polar wandering.

The images from the SRU surprisingly provided the best quality images. It was originally designed to detect faint light from stars for navigation. Instead, the team used it to capture images when Europa was illuminated by the gentle glow of sunlight reflected from Jupiter. It was quite a novel approach and allowed complex features to become far more pronounced than before. Intricate networks of ridges criss-crossing the surface were identified along with dark stains from water plumes. One feature in particular stood out, nicknamed ‘the Platypus’, it was a 37 kilometre by 67 kilometre region shaped somewhat like a platypus.

Source : NASA’s Juno Provides High-Definition Views of Europa’s Icy Shell

The post Juno Reveals Secrets About Europa’s Icy Surface appeared first on Universe Today.

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