Astro Blog

By Robert Sanders , UC Berkeley News.  Excerpt: Of the more than 4,500 stars known to have planets, one puzzling statistic stands out. Even though nearly all stars are expected to have planets and most stars form in pairs, planets that orbit both stars in a pair are rare. Of the more than 6,000 extrasolar planets, or exoplanets, confirmed to date — most of them found by NASA’s Kepler Space Telescope and the Transiting Exoplanet Survey Satellite (TESS) — only 14 are observed to orbit binary stars. There should be hundreds. Where are all the planets with two suns, like Tatooine in  Star Wars ? Astrophysicists at the University of California, Berkeley, and the American University of Beirut have now proposed a reason for this dearth of circumbinary exoplanets — and Einstein’s general theory of relativity is to blame. ...If a planet is orbiting the pair of stars, the gravitational tugs from the stars make the planet’s orbit precess, ...similar to the way the axis of a spinning top...

By Elise Cutts , Science.  Excerpt: Astronomers are planning ambitious telescopes to search for signs of life on distant planets. A newly discovered world, announced here last week at the Rocky Worlds conference and  published yesterday  in  The Astrophysical Journal Letters , might just be the perfect target. The planet, called HD 137010 b, is almost exactly Earth-size. At 355 days, its orbit is almost exactly Earth-like, too. And its star is bright and just 146 light-years away–close enough to be observed in detail with future telescopes....  Full article at https://www.science.org/content/article/earth-size-planet-spotted-yearlong-orbit . 

By Elise Cutts , Science.  Excerpt: Towering tidal waves of lava could be rolling around hot alien worlds, researchers reported last week, here at the  Rocky Worlds conference  and in a  preprint  posted on arXiv this month. The Sun and Moon drive tides on Earth, but these tidal waves would be tugged up by the intense gravitational forces endured by planets in tight orbits around their stars. For instance, lava tidal waves on the blazing-hot exoplanet 55 Cancri e—a rocky world that orbits its star every 18 hours—could rise several hundred meters high and surge at the speed of a human sprinter, says Mohammad Farhat, a planetary scientist at the University of California (UC), Berkeley who presented the modeling study. ...Scientists often look for alien air by taking the temperatures of planets’ dayside hemispheres. The presence of an atmosphere would spread heat around to the nightside, making the dayside look cooler than expected for a bare rock. But if lava wave...

By ScienceAdviser.  Excerpt: Understanding how planets form in the disks of dust and gas around newborn planets is a work in progress. Only recently have astronomers  spied planets carving out rings in the disks  by scooping up material. But some disks have a spiral structure. Is that the result of gravitational interactions in the disk itself, before planets form, or are newborn planets themselves warping the disk into a spiral? A team of astronomers say they’ve resolved this chicken-and-egg puzzle using the Atacama Large Millimeter/submillimeter Array (ALMA), a collection of 66 dish antennas high up in the Chilean Andes which can see dust in disks but not the planets themselves. If the spiral arms formed in the disk spontaneously, over time they would wind tighter, like the spring in a wind-up clock. Arms formed by planets would keep their shape as they move around the nascent star. The team used archival and new images taken over 7 years of the young star IM Lup to mak...

By McKenzie Prillaman , Science.  Excerpt: About 1,400 light-years from Earth sits a  young sunlike star surrounded by cooling gas and teensy silicate minerals . These mineral solids — some of the building blocks of rocky planets — are among the first to condense from the gas, suggesting that they’re kick-starting the creation of planets in a system much like the one earthlings call home, researchers report in the July 17  Nature . “It really is the first time we’ve seen this stage of planet formation in the process,” says planetary scientist Laura Schaefer of Stanford University, who was not involved in the new study. Observing the timeline of these early hot minerals will help researchers better understand how events unfolded billions of years ago in the solar system....  Full article at https://www.sciencenews.org/article/star-earliest-birth-planet-solar-system . 

By Jenna Ahart , Science.  Excerpt: Like the fictional planet Tatooine in  Star Wars , some exoplanets ...orbit binary pairs of stars, which cast their worlds in double sunrises and sunsets as they themselves orbit each other. Now, researchers report today in  Science Advances  that they have found  an especially unusual example of such a planet : one that orbits over and under the poles of two failed stars that loom in its skies. ...only 16 exoplanets had ever been confirmed to orbit around a binary pair—and all of those planets orbit within the plane of the stars’ orbits around each other, not over the poles. ...this peculiar planet, known rather prosaically as 2M1510 (AB) b, ...orbits... brown dwarfs, failed stars that aren’t massive enough to spark on. ...In binary systems like this one, the elliptical orbit of each object in the binary will gradually shift its orientation over time, like the axis of a spinning top tracing out a circle as the top wobble...

By Javier Barbuzano , Eos/AGU.  Excerpt: The James Webb Space Telescope offers astronomers a rare glimpse into the chemical composition of a rocky planet’s interior—and the results are “very surprising.” ...disintegrating planet, K2-22b, ...Discovered in 2015, ...orbits a small star 787 light-years away, completing one orbit every 9 hours. ...The spectroscopic results are “very surprising,” said University of Leeds astronomer  Richard Booth , who wasn’t involved with the study. “We expected to see a composition akin to Earth’s mantle with minerals like magnesium silicate, and they see hints of that,” Booth said. “You just wouldn’t expect any icy material surviving at these temperatures.”....  Full article at https://eos.org/articles/scientists-finally-get-a-good-look-at-a-disintegrating-exoplanet . 

By Damond Benningfield , Eos/AGU.  Excerpt: Earth’s future is bleak. At best, our planet will become a burned-out cinder as the Sun expands at the end of its life. At worst, it will be engulfed by the Sun, leaving no trace that it ever existed. Astronomers have found a clue as to which path Earth might follow in a star system about 4,300 light-years away. There, a rocky planet orbits the remains of a once Sun-like star at a distance similar to where Earth could park if it survives our own star’s death throes. The system “may offer a glimpse into the possible survival of planet Earth in the distant future,” according to  a new study  published in  Nature Astronomy . The system,  KMT-2020-BLG-0414L , was discovered in 2020 by the  Korea Microlensing Telescope Network , a set of three automated 1.6-meter telescopes in the Southern Hemisphere....  Full article at https://eos.org/articles/earth-may-survive-the-suns-demise . 

By Leah Crane , NewScientist.  Excerpt: Astronomers have found six new worlds that look like planets, but formed like stars. These so-called rogue worlds are between five and 15 times the mass of Jupiter, and one of them may even host the beginnings of a miniature solar system. ...From their observations, the researchers determined that planetary mass  brown dwarfs  make up about 10 per cent of the objects in NGC 1333. That is far more than expected based on models of star formation, so there may be extra processes, such as turbulence, that drive the formation of these rogue worlds. ...One of the brown dwarfs is particularly unusual – it has a ring of dust around it just like the one that formed the planets in our solar system. At about five Jupiter masses, it is  the smallest world  ever spotted with such a ring, and it may mark the beginnings of a strange, scaled-down planetary system around a failed star... .  Full article at https://www.newscientist.com...

By DANIEL CLERY , Science.  Excerpt: Living on one of the seven Earth-size planets in the TRAPPIST-1 system would be strange.... Looming ominously in the sky is an enormous red star, prone to fiery outbursts and appearing several times bigger than the Sun. Hours of the day don’t exist; each planet is tidally locked to the star so that one side is forever scorchingly hot, the other eternally frozen. Along the margin dividing the day- and nightsides—the only place with a tolerable climate—a ceaseless wind blows and the star hangs on the horizon, in perpetual sunset. A short stroll into the dark side brings your planetary companions into view. Every few days one or more passes overhead like a floating lantern, larger than the Moon. ...the quest to learn whether one of the TRAPPIST-1 planets could make a comfortable home for our imaginary observer has been an exercise in frustration. When the  seven known planets around TRAPPIST-1 were revealed in 2017 , they were ...the best plac...

https://eos.org/articles/tatooine-trisolaris-thessia-sci-fi-exoplanets-reflect-real-life-discoveries By Kimberly M. S. Cartier , Eos/AGU.  Excerpt: Astronomers have discovered more than 5,000 extrasolar planets since the 1995 discovery of 51 Pegasi b. When the discoveries  started pouring in , astronomers quickly realized that few exoplanets resembled  anything in the solar system . ...A new study led by Puranen examined how the discovery of real exoplanets has influenced portrayals of fictional ones. The researchers showed that as scientists discovered that real-life exoplanets rarely resembled Earth, sci-fi exoplanets became less Earth-like, too. ...The analysis showed that “fictional exoplanets from after the real-life discovery of exoplanets were less likely to have intelligent native life and less likely to have established populations of non-native humans,” Puranen said. Sci-fi exoplanets became less Earth-like and more likely to feature nonintelligent native biosph...

https://www.science.org/content/article/planets-around-dead-stars-offer-glimpse-solar-system-s-future-after-sun-swallows-us By JONATHAN O’CALLAGHAN , Science.  Excerpt: In about 5 billion years the Sun will balloon up into a red giant, consuming Mercury, probably Venus, and maybe even Earth. But even if the outer planets avoid being swallowed up, they might eventually get pulled in or ejected from the Solar System. A new discovery suggests they can survive intact. Using NASA’s JWST space telescope, astronomers have for the first time directly imaged planets on Solar System–like orbits around white dwarfs, the dead stars left after Sun-like stars swell into red giants and subside. The planets follow orbits resembling those of the giant planets in the outer Solar System—big enough for them to have escaped the inferno.... For GSS A Changing Cosmos chapter 1.

https://www.science.org/content/article/astronomers-stunned-six-planet-system-frozen-time By DANIEL CLERY , Science.  Excerpt: Astronomers have discovered a highly unusual planetary system ...six planets, all bigger than Earth but smaller than Neptune, a variety that is absent in our Solar System but common across the Milky Way. Moreover, all of the planets orbit in rhythmic harmony, which suggests the system has remained undisturbed since its formation billions of years ago. The brightness of the star, its relative proximity to Earth, and its six orbiting oddities could make the system a perfect laboratory for studying the formation of these planets, known as sub-Neptunes. ...the study, published today in  Nature . The planets’ orbits are all tighter than Mercury’s. ...a mysterious [size] gap persists: Planets between 1.5 and two Earth diameters seem almost entirely absent and astronomers are eager to know why. ...The new system’s discovery involved two space telescopes, mult...

https://www.bbc.com/news/science-environment-66974738 By Jonathan Amos , The Guardian.  Excerpt: Jupiter-sized "planets" free-floating in space, unconnected to any star, have been spotted by the James Webb Space Telescope (JWST). What's intriguing about the discovery is that these objects appear to be moving in pairs. Astronomers are currently struggling to explain them. The telescope observed about 40 pairs in a fabulously detailed new survey of the famous Orion Nebula. They've been nicknamed Jupiter Mass Binary Objects, or "JuMBOs" for short. ..."Gas physics suggests you shouldn't be able to make objects with the mass of Jupiter on their own, and we know single planets can get kicked out from star systems. But how do you kick out pairs of these things together? Right now, we don't have an answer. It's one for the theoreticians," the European Space Agency's (Esa) senior science adviser told BBC News.... 

https://eos.org/articles/subsurface-oceans-could-boost-exoplanet-habitability By  Javier Barbuzano , Eos/AGU.  Excerpt: A group of researchers led by planetary scientist  Lujendra Ojha  of Rutgers University crunched the numbers to reveal that our galaxy is likely brimming with planets hosting subsurface oceans like those on  Enceladus ,  Europa , and  Ganymede . “Before we started to consider this subsurface water, it was estimated that around one rocky planet [orbiting] every 100 stars would have liquid water,” Ojha said. “The new model shows that if the conditions are right, this could approach one planet per star.”... 

https://www.nasa.gov/feature/goddard/2023/webb-detects-water-vapor-in-rocky-planet-forming-zone By NASA.  Excerpt: Water is essential for life as we know it. However, scientists debate how it reached the Earth and whether the same processes could seed rocky exoplanets orbiting distant stars. New insights may come from the planetary system PDS 70, located 370 light-years away. The star hosts both an inner disk and outer disk of gas and dust, separated by a 5 billion-mile-wide (8 billion kilometer) gap, and within that gap are two known gas-giant planets. New measurements by NASA’s James Webb Space Telescope’s MIRI (Mid-Infrared Instrument) have detected water vapor in the system’s inner disk, at distances of less than 100 million miles (160 million kilometers) from the star – the region where rocky, terrestrial planets may be forming. (The Earth orbits 93 million miles from our Sun.) This is the first detection of water in the terrestrial region of a disk already known to host two o...

https://www.kqed.org/forum/2010101893676/aomawa-shields-on-searching-for-life-in-space-and-at-home KQED podcast.  Excerpt: Does it matter if life exists on another planet? To UC Irvine astrobiologist Aomawa Shields it matters in the same way that a mountain matters and screams to be climbed: not knowing is unbearable. Shields has devoted her career to studying the climate and habitability of exoplanets to further the search for extraterrestrial life. She’s also one of very few Black women in a field dominated by white men and a classically trained actor. We talk to her about her journey as a scientist and an artist and her new book “Life on Other Planets: A Memoir of Finding My Place in the Universe.”... See also TED Talk,  How we'll find life on other planets  

https://eos.org/articles/nearby-volcano-planet-likely-fueled-by-tidal-heating By Javier Barbuzano , Eos/AGU.  Excerpt: An unusual planetary dance has produced an Earth-sized exoplanet brimming with volcanoes, likely furnished with an atmosphere, and maybe even containing water on its surface. Astronomers discovered this odd world orbiting a  red dwarf star  right in our galactic neighborhood—just 90 light-years away. The exoplanet, known as LP 791-18 d, orbits a red dwarf already known to host two other planets:  LP 791-18 b , a scorched, rocky world orbiting extremely close to the star, and  LP 791-18 c , a sub-Neptune 7 times more massive than Earth made of gas or icy material. The finding comes after a group of researchers led by astrophysicist  Björn Benneke  of the Université de Montréal in Canada used NASA’s recently retired  Spitzer Space Telescope  to take a closer look at the system....

https://www.nasa.gov/feature/goddard/2023/webb-looks-for-fomalhaut-s-asteroid-belt-and-finds-much-more By NASA.  Excerpt: Astronomers used NASA’s James Webb Space Telescope to image the warm dust around a nearby young star, Fomalhaut, in order to study the first asteroid belt ever seen outside of our solar system in infrared light. But to their surprise, the dusty structures are much more complex than the asteroid and Kuiper dust belts of our solar system. Overall, there are three nested belts extending out to 14 billion miles (23 billion kilometers) from the star; that’s 150 times the distance of Earth from the Sun. The scale of the outermost belt is roughly twice the scale of our solar system’s Kuiper Belt of small bodies and cold dust beyond Neptune. The inner belts – which had never been seen before – were revealed by Webb for the first time. ...The team’s results are being published in the journal  Nature Astronomy . See also  New York Times article .... 

https://skyandtelescope.org/astronomy-news/star-caught-swallowing-a-planet/ By Camille M. Carlisle, Sky & Telescope.  Excerpt: For the first time, astronomers have witnessed a star eat an exoplanet. The dinner bell has struck for a star in the constellation Aquila, the Eagle. Reporting in the May 4th  Nature , Kishalay De (MIT) and a team of astronomers watched the star belch and brighten in a way that suggests  it swallowed a closely orbiting planet . The star in question is a nondescript Sun-like star about 12,000 light-years away. Pre-outburst observations indicate it was slightly bloated, perhaps twice as wide as the Sun, and entering its golden years. This time in a star’s life can be a dangerous one for planets. As the star finishes fusing the hydrogen in its core, it brightens and swells. Eventually, it can swell enough to engulf the closest worlds, destroying them in a fiery furnace..... See also Science article  A dying star consumes a planet, foreshadow...