Tag: exoplanets

Webb takes infrared image of exoplanet

10:02 am

A Jupiter-sized exoplanet imaged by Webb
Click for original image.

Cool image time! Using the Webb Space Telescope, scientists have taken an infrared false color image of a multi-Jupiter-sized exoplanet located only twelve light years away and orbiting the K-type star Epsilon Indi A.

That picture, cropped, reduced, and sharpened to post here, is to the right. The light of the star, indicated by the star symbol, has been blocked by Webb’s coronagraph, the size of which is shown by the dashed circle. The exoplanet is the orange blob to the left.

[This exoplanet] is one of the coldest exoplanets to be directly detected, with an estimated temperature of 35 degrees Fahrenheit (2 degrees Celsius) — colder than any other imaged planet beyond our solar system, and colder than all but one free-floating brown dwarf. The planet is only around 180 degrees Fahrenheit (100 degrees Celsius) warmer than gas giants in our solar system. This provides a rare opportunity for astronomers to study the atmospheric composition of true solar system analogs.

The data also revealed that the exoplanet is twice as massive as expected and has a slightly different orbit than expected based on previous less precise data.

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Astronomers discover an exoplanet with the most eccentric orbit so far found

9:41 am

Using the TESS space telescope, astronomers have discovered a gas giant exoplanet with the most eccentric orbit so far found, circling a star about 1,100 light years away.

On Jan. 12, 2020, TESS picked up a possible transit of the star TIC 241249530. Gupta and his colleagues at Penn State determined that the transit was consistent with a Jupiter-sized planet crossing in front of the star. They then acquired measurements from other observatories of the star’s radial velocity, which estimates a star’s wobble, or the degree to which it moves back and forth, in response to other nearby objects that might gravitationally tug on the star. Those measurements confirmed that a Jupiter-sized planet was orbiting the star and that its orbit was highly eccentric, bringing the planet extremely close to the star before flinging it far out.

Prior to this detection, astronomers had known of only one other planet, HD 80606 b, that was thought to be an early hot Jupiter. That planet, discovered in 2001, held the record for having the highest eccentricity, until now.

The exoplanet’s orbit is presently 167 days long, at its closest stellar approach dipping 10 times closer to its star than Mercury is from the Sun, and at its farthest point zipping just beyond Earth’s distance.

Computer simulations suggest that in a billion years this orbit will decay into a more circular orbit close to the star, turning this gas giant into a hot Jupiter roasted by its star continually.

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Webb infrared spectroscopy detects differences between morning and evening on tidally-locked exoplanet

9:36 am

Webb spectroscopic data
Click for original image.

Astronomers using Webb Space Telescope’s infrared spectroscopy have now detected distinct differences in the morning and evening atmosphere of a tidally-locked gas giant exoplanet.

The graph, cropped, reduced, sharpened, annotated to post here, shows the differences. From the caption:

Researchers using NASA’s James Webb Space Telescope have finally confirmed what models have previously predicted: An exoplanet has differences between its eternal morning and eternal evening atmosphere. WASP-39 b, a giant planet with a diameter 1.3 times greater than Jupiter, but similar mass to Saturn that orbits a star about 700 light-years away from Earth, is tidally locked to its parent star. This means it has a constant dayside and a constant nightside—one side of the planet is always exposed to its star, while the other is always shrouded in darkness.

Using Webb’s NIRSpec (Near-Infrared Spectrograph), astronomers confirmed a temperature difference between the eternal morning and eternal evening on WASP-39 b, with the evening appearing hotter by roughly 300 Fahrenheit degrees (about 200 Celsius degrees). They also found evidence for different cloud cover, with the forever morning portion of the planet being likely cloudier than the evening.

The actual temperatures of each terminator are quite hot, approximately 1,150 and 1450 degrees Fahrenheit respectively. Computer modeling suggests “the prevailing winds are likely moving from the night side across the morning terminator, around the dayside, across the evening terminator and then around the nightside,” with wind speeds thousands of miles per hour.

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Webb: An exoplanet in the habitable zone with a possible nitrogen/CO2 atmosphere and water ocean

8:51 am

Using the Webb Space Telescope, astronomers have obtained new transiting spectroscopy of a “mini-Neptune-sized” exoplanet that circles in the habitable zone a red dwarf star about 48 light years away and have concluded that it appears to have a nitrogen/carbon dioxide atmosphere and even a water ocean.

While it is still only a tentative result, the presence of a nitrogen-rich atmosphere on LHS 1140 b would suggest the planet has retained a substantial atmosphere, creating conditions that might support liquid water. This discovery favors the water-world/snowball scenario as the most plausible.

Current models indicate that if LHS 1140 b has an Earth-like atmosphere, it would be a snowball planet with a vast “bull’s-eye” ocean measuring about 4,000 kilometers in diameter, equivalent to half the surface area of the Atlantic Ocean. The surface temperature at the centre of this alien ocean could even be a comfortable 20 degrees Celsius [68 degrees Fahrenheit]. [emphasis mine]

You can read the preprint of the paper here [pdf].

The highlighted phrase must be noted. These results contain a lot of uncertainties and assumptions. However, the data is tantalizing, to say the least, and justify more observations using Webb. The scientists argue in their paper that because there are only about eight transits of the exoplanet per year — requiring several years of observations to pin down this data more precisely — and because Webb has a limited life expectancy as an infrared observatory, this star should get observational priority.

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Webb: Hot Jupiter exoplanet has atmosphere with the smell of rotten eggs

9:20 am

Using spectroscopy from the infrared Webb Space Telescope, astronomers have measured some of the molecules in exoplanet HD 189733 b, one of the first hot Jupiter exoplanets ever discovered, and found it has an atmosphere rich in hydrogen sulfide, which emits a smell like rotten eggs.

In addition to detecting hydrogen sulfide, the team analyzed the planet’s oxygen and carbon content, pinpointing water, carbon dioxide and carbon monoxide as major components of the planetary atmosphere. Measuring these heavy elements allows astronomers to compare the composition of exoplanets to that of gas giants in our solar system like Jupiter and Uranus.

The exoplanet, about 64 light years away, has an orbit lasting only about two Earth days, with atmospheric temperatures has hot as 1,700 degrees Fahrenheit.

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The “Vulcan” exoplanet discovered in 2018 now refuted

9:52 am

In 2018 astronomers had thought they had detected an exoplanet orbiting the star 40 Eridani A — which is where in Star Trek the home world Mr. Spock was supposed to be located.

That discovery has now been refuted by much more precise observations.

[T]he planet signal is really the flickering of something on the star’s surface that coincides with a 42-day rotation – perhaps the roiling of hotter and cooler layers beneath the star’s surface, called convection, combined with stellar surface features such as spots and “plages,” which are bright, active regions.

In other words, this exoplanet does not exist. For once at least life did not imitate art.

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A planet with the density of cotton candy?

10:32 am

The uncertainty of science: According to data obtained from ground-based telescopes of a newly discovered transiting exoplanet, that planet has the density of cotton candy.

This new planet, located 1,200 light-years from Earth, is 50% larger than Jupiter but seven times less massive, giving it an extremely low density comparable to that of cotton candy. “WASP-193b is the second least dense planet discovered to date, after Kepler-51d, which is much smaller,” explains Khalid Barkaoui, a Postdcotral Researcher at ULiège’s EXOTIC Laboratory and first author of the article published in Nature Astronomy. Its extremely low density makes it a real anomaly among the more than five thousand exoplanets discovered to date. This extremely-low-density cannot be reproduced by standard models of irradiated gas giants, even under the unrealistic assumption of a coreless structure.”

Such a gas giant is not impossible. For example, Saturn’s density is so low that if you could find an ocean large enough it would float. The scientists theorize that this exoplanet is likly comprised mostly of hydrogen and helium.

Nonetheless, there are phenomenon here that we certainly do not understand.

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TESS resumes science operations

9:26 am

Engineers have corrected the issue that put the space telescope TESS into safe mode on April 8, 2024 and have resumed science operations.

The operations team determined this latest safe mode was triggered by a failure to properly unload momentum from the spacecraft’s reaction wheels, a routine activity needed to keep the satellite properly oriented when making observations. The propulsion system, which enables this momentum transfer, had not been successfully repressurized following a prior safe mode event April 8. The team has corrected this, allowing the mission to return to normal science operations. The cause of the April 8 safe mode event remains under investigation.

As for that April 8th safe mode, though engineers were able to return the spacecraft to normal operations after about a week, that they still do not know what caused it remains a concern.

TESS takes high resolution survey images of 93% of the sky about once per month. By comparing the data from each scan, scientists have discovered so far more than 300 transiting exoplanets as well as many supernovae and other phenomenon related to variable stars.

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A molecule found by Rosetta on Comet 67P/C-G proves discovering life on exoplanets will not be easy

12:50 pm

The uncertainty of science: Scientists have long assumed that the molecule dimethyl sulfide (DMS) is an excellent biosignature of life, since it is only produced by life here on Earth. When they discovered it in the atmosphere of an exoplanet last year many thought, especially in the media, that it proved that life existed on that exoplanet.

A scientist who had worked on the Rosetta mission to the Comet 67P/C-G thought otherwise, that DMS was not a reliable biosignature and quickly proved it.

Just 1 day of data from Rosetta’s mass spectrometer, an instrument that can identify molecules by their specific weights, was enough for [Nora Hänni] and her colleagues to find DMS. She says lab experiments will now be needed to pin down exactly how DMS forms in space, where ultraviolet light and cosmic rays can power the synthesis of complex organic molecules. Another important question is whether comets could deliver significant amounts of DMS to a planet—and perhaps account for detections like the K2-18b claim. “If it impacted the atmosphere, it could contaminate the atmosphere of the planet,” Noack says, potentially complicating searches for alien life.

Like the fake news in 2020 that life was found in the atmosphere of Venus (it wasn’t), it is a big mistake to use the detection of one molecule to assume it is evidence of life on an alien world. The universe is far more complicated.

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Another exoplanet found in habitable zone

9:55 am

Astronomers using both space- and ground-based telescopes have confirmed the existence of another rocky exoplanet inside the habitable zone of its star.

The star is a red dwarf 137 light years away. The exoplanet, dubbed TOI-175 b, is estimated to be larger than Earth, with a diameter 1.5 times that of our home planet. It orbits its star every nineteen days. Even more intriguing, the data suggests this star has a second exoplanet even better positioned in the habitable zone that would be the smallest habitable-zone exoplanet so far found, about the size of Earth.

The second planet however is not yet confirmed.

This discovery is no longer very unique. In the past few years astronomers have discovered a plethora of Earth-sized exoplanets, many in the habitable zone.

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Astronomers discover Earth-sized exoplanet roasted by a Sunlike star

10:18 am

Using data from the TESS space telescope, astronomers have discovered an Earth-sized exoplanet in a 4.2 day orbit around a G-type star like our Sun about 70 light years away.

The tidally locked planet is very close to Earth size (it is approximately 1.1 times the diameter of our own planet) and it’s orbiting a star that’s similar to the size of our Sun (the star is about 0.91 the size and 0.99 the mass of the Sun).

The star in this system is a G-type star, the same type as our Sun. But HD 63433 d orbits much closer to its star than we do, with a minuscule 4.2 day long “year” and extremely high temperatures on its dayside.

To read the research paper, go here. At an estimated age of only 400 million years, this exoplanet and its solar system of at least two other planets is much younger than the 4.5-billion-year-old Earth. Though the press release and paper note the possibility that it is similar in many ways to Io, a volcanic planet covered with lava, we don’t know this. All we know is that it is roasted by its star by orbiting so close to it.

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Astronomers: A solar system with six Earth-sized planets orbiting in perfect resonance

9:38 am

The resonances of this exo-solar system
Click for original image.

Astronomers today announced the discovery of a solar system with six Earth-sized exoplanets that orbit their Sun-like star in a synchronized manner, their orbits in a gravitational lock-step called resonance.

The graphic to the right illustrates that pattern. From the press release:

While multi-planet systems are common in our galaxy, those in a tight gravitational formation known as “resonance” are observed by astronomers far less often. In this case, the planet closest to the star makes three orbits for every two of the next planet out – called a 3/2 resonance – a pattern that is repeated among the four closest planets.

Among the outermost planets, a pattern of four orbits for every three of the next planet out (a 4/3 resonance) is repeated twice. And these resonant orbits are rock-solid: The planets likely have been performing this same rhythmic dance since the system formed billions of years ago. Such reliable stability means this system has not suffered the shocks and shakeups scientists might typically expect in the early days of planet formation – smash-ups and collisions, mergers and breakups as planets jockey for position. And that, in turn, could say something important about how this system formed. Its rigid stability was locked in early; the planets’ 3/2 and 4/3 resonances are almost exactly as they were at the time of formation. More precise measurements of these planets’ masses and orbits will be needed to further sharpen the picture of how the system formed.

All the planets have orbits less than 55 days long, and though all have masses less than six Earth-masses, data suggests they more resemble Neptune because of their expanded gaseous make-up caused by the close orbits to the star.

Future observations are planned, most especially with Webb because its infrared capability will detect much of the chemistry of this system.

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Astronomers detect nano-sized quartz crystals in atmosphere of exoplanet

9:33 am

Using both the Hubble and Webb space telescopes in space, astronomers have detected nano-sized quartz crystals in the atmosphere of a Jupiter-class exoplanet orbiting its star every 3.7 days.

Silicates (minerals rich in silicon and oxygen) make up the bulk of Earth and the Moon as well as other rocky objects in our solar system, and are extremely common across the galaxy. But the silicate grains previously detected in the atmospheres of exoplanets and brown dwarfs appear to be made of magnesium-rich silicates like olivine and pyroxene, not quartz alone – which is pure SiO2.

The result from this team, which also includes researchers from NASA’s Ames Research Center and NASA’s Goddard Space Flight Center, puts a new spin on our understanding of how exoplanet clouds form and evolve. “We fully expected to see magnesium silicates,” said co-author Hannah Wakeford, also from the University of Bristol. “But what we’re seeing instead are likely the building blocks of those, the tiny ‘seed’ particles needed to form the larger silicate grains we detect in cooler exoplanets and brown dwarfs.”

These tiny quartz crystals are condensing out in the clouds themselves, due to the high temperatures and pressures there. The exoplanet itself is unusual because though its mass is one half that of Jupiter, its volume is seven times larger. This gives it a very large and deep atmosphere, thus providing the environment for crystal formation.

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The possibility of more than one exoplanet sharing the same orbit

9:27 am

PDS 70, as seen by ALMA
The Trojan debris clouds around PDS 70, as seen by ALMA

The uncertainty of science: Astronomers have detected evidence that suggests the possibility of more than one exoplanet sharing the same orbit around PDS 70, a star 400 light years away.

This young star is known to host two giant, Jupiter-like planets, PDS 70b and PDS 70c. By analysing archival ALMA observations of this system, the team spotted a cloud of debris at the location in PDS 70b’s orbit where Trojans are expected to exist.

Trojans occupy the so-called Lagrangian zones, two extended regions in a planet’s orbit where the combined gravitational pull of the star and the planet can trap material. Studying these two regions of PDS 70b’s orbit, astronomers detected a faint signal from one of them, indicating that a cloud of debris with a mass up to roughly two times that of our Moon might reside there.

The press release — as well as most news reports — touts the possibility that they have found a second planet in this orbit. They have not, and are likely not going to. As noted above, the data indicates the presence of “a cloud of debris”, which is most likely a clustering of Trojan asteroids, just as the more than 12,000 asteroids we see in the two Trojan points in Jupiter’s orbit.

Nonetheless, this is the first detection of what appears to be a Trojan clustering in the accretion disk of a young star.

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Astronomers detect vaporized elements in atmosphere of hot Jupiter-sized exoplanet

8:23 am

Using the Gemini telescope in Hawaii, astronomers have detected several elements in atmosphere of hot Jupiter-sized exoplanet, dubbed WASP-76b, that would normally be found in rocks, but here are vaporized because the exoplanet orbits so close to its star.

In 2020 and 2021, using Gemini North’s MAROON-X (a new instrument specially designed to detect and study exoplanets), Pelletier and his team observed the planet as it passed in front of its host star on three separate occasions. These new observations uncovered a number of rock-forming elements in the atmosphere of WASP-76b, including sodium, potassium, lithium, nickel, manganese, chromium, magnesium, vanadium, barium, calcium, and, as previously detected, iron.

Due to the extreme temperatures of WASP-76b’s atmosphere, the elements detected by the researchers, which would normally form rocks here on Earth, are instead vaporized and thus present in the atmosphere in their gaseous forms. While these elements contribute to the composition of gas giants in our Solar System, those planets are too cold for the elements to vaporize into the atmosphere making them virtually undetectable.

The data not only suggests such elements exist in the solar system’s gas giants, but that such elements are common in solar systems elsewhere. That possibility increases the chances of other planets like Earth, capable of sustaining life as we know it, in addition to sustaining life as we don’t know it.

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Webb finds Earth-sized exoplanet likely too hot to have atmosphere

9:25 am

The uncertainty of science: Using the infrared Webb Space Telescope, scientists have measured the temperature of the Earth-sized exoplanet, dubbed Trappist-1b, and found its temperature is probably too hot to have atmosphere.

The red dwarf star Trappist-1is about 40 light years from Earth, and in 2017 was found to have a solar system of seven exoplanets, all rocky terrestrial planets like the inner planets of our solar system. Trappist-1b is the innermost exoplanet. To measure its temperature, Webb observed the star while the planet was eclipsed by the star as well as when it was not, and measured the tiny difference in infrared light.

The team analyzed data from five separate secondary eclipse observations. “We compared the results to computer models showing what the temperature should be in different scenarios,” explained Ducrot. “The results are almost perfectly consistent with a blackbody made of bare rock and no atmosphere to circulate the heat. We also didn’t see any signs of light being absorbed by carbon dioxide, which would be apparent in these measurements.”

As this was the innermost of the star’s solar system, it is also the one most likely to lack an atmosphere. Webb’s observations of the system continue, so there is a chance that data about the other exoplanets will eventually tell us more about them.

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Webb detects “hot sand clouds” in atmosphere of exoplanet

10:40 am

Using the Webb Space Telescope, astronomers have detected “hot sand clouds” in atmosphere of exoplanet 40 light years away, along with evidence of water, methane, carbon monoxide, carbon dioxide, sodium, and potassium.

You can read the paper here [pdf]. The exoplanet itself appears to have some features that resemble that of a brown dwarf, or failed star, instead of an exoplanet.

Although VHS 1256 b is more on the heavier side of the known exoplanets, its gravity is relatively low compared to more massive brown dwarfs. Such very low-mass stars can only burn deuterium for a relatively short duration. Consequently, the planet’s silicate clouds can appear and remain higher in its atmosphere, where the JWST can detect them. Another reason its skies are so turbulent is the planet’s age. In astronomical terms, it is pretty young. Only 150 million years have passed since it formed. The planet’s heat stems from the recent formation process – and it will continue to change and cool over billions of years.

The sand clouds are hot, in the range of 1,500 degrees Fahrenheit.

These results were obtained as part of an early-release program from Webb, and illustrate the potential of the infrared space telescope for learning many specific details about brown dwarfs and exoplanets.

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VLT takes picture of exoplanet

9:20 am

VLT's picture of exoplanet
Click for original image.

The ground-based Very Large Telescope (VLT) in Chile has successfully taken a picture of an exoplanet four to six times larger than Jupiter that is circling its star at about the same distance as Saturn.

That picture, cropped to post here, is to the right. Other data from other observatories had suggested the star AF Leporis, 87.5 light years away, might have an exoplanet, so astronomers decided to focus VLT on it to see if it could spot it.

AF Leporis is about as massive and as hot as the sun, ESO wrote in the statement, and in addition to its one known planet the star also has a disk of debris similar to the solar system’s Kuiper Belt. AF Leporis is, however, much younger than the sun. At 24 million years old, it is about 200 times younger than our star. This young age makes AF Leporis and its planetary system especially intriguing for astronomers as it can provide important insights into the evolution of our own solar system.

To snap this picture, the VLT had to use adaptive optics to smooth out the fuzziness produced by the Earth’s atmosphere, while also blocking out the star’s own light (as shown by the black disk in the image).

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TESS finds a second Earthsize planet orbiting in the habitable zone of a star

9:37 am

TESS solar system

The orbiting survey telescope TESS has discovered a second Earthsize planet in a solar system of four exoplanets.

The graphic to the right, a screen capture from a short video provided by the press release, shows these four exoplanets. Planet D had previously been discovered. Planet E is the new discovery, and is thought to be 95% Earth’s mass and likely terrestrial in make-up. Both are near the inner edge of the habitable zone.

TOI 700 is a small, cool M dwarf star located around 100 light-years away in the southern constellation Dorado. In 2020, Gilbert and others announced the discovery of the Earth-size, habitable-zone planet d, which is on a 37-day orbit, along with two other worlds.

The innermost planet, TOI 700 b, is about 90% Earth’s size and orbits the star every 10 days. TOI 700 c is over 2.5 times bigger than Earth and completes an orbit every 16 days. The planets are probably tidally locked, which means they spin only once per orbit such that one side always faces the star, just as one side of the Moon is always turned toward Earth.

This discovery only underlines the infinite possibilities and variables that exist for life on other worlds. These planets might be similar in mass to the Earth and get about the same heat/light energy from their sun, but the star is very different, their orbits are very different, and their environment is very different.

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Astronomers determine that two super-Earths are not as rocky as previously believed

10:32 am

Using observations from both the Hubble Space Telescope and the now retired Spitzer infrared space telescope, astronomers now think that two super-Earth-sized explanets are not as rocky as previously believed, and are in fact liquid worlds with as much as half their make-up comprised of water. From the press release:

Water wasn’t directly detected at Kepler-138 c and d, but by comparing the sizes and masses of the planets to models, astronomers conclude that a significant fraction of their volume – up to half of it – should be made of materials that are lighter than rock but heavier than hydrogen or helium (which constitute the bulk of gas giant planets like Jupiter). The most common of these candidate materials is water.

“We previously thought that planets that were a bit larger than Earth were big balls of metal and rock, like scaled-up versions of Earth, and that’s why we called them super-Earths,” explained Björn Benneke, study co-author and professor of astrophysics at the University of Montreal. “However, we have now shown that these two planets, Kepler-138 c and d, are quite different in nature and that a big fraction of their entire volume is likely composed of water. It is the best evidence yet for water worlds, a type of planet that was theorized by astronomers to exist for a long time.”

With volumes more than three times that of Earth and masses twice as big, planets c and d have much lower densities than Earth. This is surprising because most of the planets just slightly bigger than Earth that have been studied in detail so far all seemed to be rocky worlds like ours. The closest comparison, say researchers, would be some of the icy moons in the outer solar system that are also largely composed of water surrounding a rocky core.

This data simply underlines a basic point: The information we have of all exoplanets is sparse, practically nil. Any conclusions about their make-up is an educated guess, at best. Even now the conclusion that these are water worlds should be treated with great skepticism.

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