Exoplanets – worlds of other suns

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Webb confirms its first exoplanet

Researchers have confirmed the presence of an exoplanet, a planet that orbits another star, using the NASA/ESA/CSA James Webb Space Telescope for the first time. Formally classified as LHS 475 b, the planet is almost exactly the same size as our own, clocking in at 99% of Earth’s diameter.

https://www.esa.int/Science_Exploration ... _exoplanet

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Discovery Alert: Two 'Nearby' Worlds Might be Habitable
https://exoplanets.nasa.gov/news/1719/d ... habitable/
By Pat Brennan, NASA's Exoplanet Exploration Program

The discovery: Two planets about as massive as Earth orbit a red-dwarf star only 16 light-years away – nearby in astronomical terms. The planets, GJ 1002 b and c, lie within the star’s habitable zone, the orbital distance that could allow liquid water to form on a planet’s surface if it has the right kind of atmosphere.

Key facts: Whether red-dwarf stars are likely to host habitable worlds is a subject of scientific debate. On the minus side, these stars – smaller, cooler, but far longer-lived than stars like our Sun – tend to flare frequently in their youth. Such flares could potentially strip the atmospheres from closely orbiting planets, and the two planets orbiting GJ 1002 are close indeed. Planet b, with a mass slightly higher than Earth’s, is the closer of the two. Its year, once around the star, lasts only 10 days. Planet c, about a third more massive than Earth, takes about 20 days to orbit the star.
The latest

On the plus side, however, GJ 1002 seems to be mature enough to have gotten over its youthful tantrums, and now appears quiet. It’s even possible that the early flaring helped build up a variety of molecules on the planets’ surfaces that could be used later, during the star’s quiet period, by any developing life forms that might be present.

Details: An international team led by Alejandro Suárez Mascareño of the University of La Laguna, Spain, discovered the two new planets using radial velocity measurements – that is, detecting the “wobbles” of the parent star caused by gravitational tugs from orbiting planets. As the planets move toward the far side of the star, they pull the star away from us, causing the star’s light to shift toward the red end of the spectrum. As the planets move toward the star’s near side, they pull the star in our direction, shifting its light toward the blue. The planetary tugs on GJ 1002 are tiny, about 4.3 feet (1.3 meters) per second – equivalent to moving at about 3 miles per hour (4.8 kilometers per hour). Such small movements are difficult to detect.

The radial velocity method, which also reveals how massive the planets are, has yielded more than 1,000 confirmed detections of exoplanets. The most detections, however, have been notched using the “transit” method – watching for a tiny dip in starlight as a planet crosses in front of its star – with nearly 4,000 confirmed detections.

To make its radial velocity measurements, the science team relied on instruments called spectrographs, which measure variations in light. The spectrographs used to discover GJ 1002 b and c were part of two collaborative observation programs: The Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO), and the Calar Alto high-Resolution search for M-dwarfs with Exoearths with Near-infrared and optical Échelle Spectrographs (CARMENES).

Fun facts: The new planets join 10 others in a fairly exclusive category: small worlds in the “conservative” habitable zone that are less than 1.5 times the size of Earth or less than five times as massive. If we loosen the membership criteria a bit – slightly larger planets in the “optimistic” habitable zone – the group expands to about 40 exoplanets, or planets beyond our solar system. The conservative habitable zone is a stricter boundary for the region around a star that might allow planets to harbor water; optimistic habitable zones expand that boundary a bit. Any habitable zone estimate is a rough approximation. So far, none of these worlds’ atmospheres have been fully analyzed – and many might not possess atmospheres at all.

The discoverers: A paper on the discovery, “Two temperate Earth-mass planets orbiting the nearby star GJ 1002,” by A. Suárez Mascareño and his team, has been accepted for publication in the journal, Astronomy & Astrophysics. The planets were entered into NASA’s Exoplanet Archive on Dec. 22, 2022.

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An Earth-sized Planet around an M5 Dwarf Star at 22 pc
https://arxiv.org/abs/2302.00699

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Astronomers discover potential habitable exoplanet only 31 light-years from Earth
By Laurence Tognetti
https://www.space.com/15693-telescopes- ... guide.html

Although astronomers have discovered more than 5,200 exoplanets, less than 200 are rocky — so the discovery of a new terrestrial exoplanet is always exciting.

In a new study, a team of 50 astronomers from around the world have confirmed the existence of exoplanet Wolf 1069 b, which orbits a red dwarf star, Wolf 1069, only 31 light-years from Earth. What makes this discovery particularly intriguing is that Wolf 1069 b is potentially a rocky world, at about 1.26 the mass of Earth and 1.08 the size. Wolf 1069 b also orbits in its star's habitable zone, making it a prime candidate for liquid water to potentially exist on its surface.

"When we analyzed the data of the star Wolf 1069, we discovered a clear, low-amplitude signal of what appears to be a planet of roughly Earth mass," Diana Kossakowski, an astronomer at the Max Planck Institute for Astronomy in Germany and lead author on the new research, said in a statement. "It orbits the star within 15.6 days at a distance equivalent to one-15th of the separation between the Earth and the sun."

[firestar464]

https://www.forbes.com/sites/jamiecarte ... en-planet/

Frankly unsure this is necessary as by the time 1K years has passed, our tech will be good enough to do this in much less time. The only value I can see for this project is to send out another time capsule like Voyager or something, but we can wait a few more decades to do that.

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Researchers focus AI on finding exoplanets
https://phys.org/news/2023-02-focus-ai-exoplanets.html
by Alan Flurry, University of Georgia

New research from the University of Georgia reveals that artificial intelligence can be used to find planets outside of our solar system. The recent study demonstrated that machine learning can be used to find exoplanets, information that could reshape how scientists detect and identify new planets very far from Earth.

"One of the novel things about this is analyzing environments where planets are still forming," said Jason Terry, doctoral student in the UGA Franklin College of Arts and Sciences department of physics and astronomy and lead author on the study. "Machine learning has rarely been applied to the type of data we're using before, specifically for looking at systems that are still actively forming planets."

The first exoplanet was found in 1992, and though more than 5,000 are known to exist, those have been among the easiest for scientists to find. Exoplanets at the formation stage are difficult to see for two primary reasons. They are too far away, often hundreds of lights years from Earth, and the disks where they form are very thick, thicker than the distance of the Earth to the sun. Data suggests the planets tend to be in the middle of these disks, conveying a signature of dust and gases kicked up by the planet.

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https://arxiv.org/abs/2302.02810

The 10 parsec sample in the Gaia era: first update
C. Reyle, K. Jardine, P. Fouque, J. A. Caballero, R. L. Smart, A. Sozzetti

We provide an update of the catalogue of all objects closer than 10 pc from the Sun. This list shows the high variety of objects contained in the immediate vicinity of the Sun.
It contains 541 objects divided between 371 stars, including 21 white dwarfs, 85 brown dwarfs, and 85 confirmed exoplanets in 336 systems. It contains the most recent astrometry from the last Gaia data release when available. As (Reylé et al., 2021) already pointed out, the updates concern close binaries, brown dwarfs, and exoplanets, and we expect that in the future the number of stars and brown dwarfs will be superseded by exoplanets. In addition, we explore the new products offered by the most recent Gaia DR3, including astrophysical parameters, additional radial velocities, non single star orbital solutions, and variability parameters. This list provides a set of benchmark stars to be studied in detail with current and forthcoming instruments. More parameters, in particular on the non-single stars (including exoplanets) are expected in the forthcoming Gaia data releases.

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Massive 'forbidden planet' orbits a strangely tiny star only 4 times its size
By Robert Lea


published about 16 hours ago

The discovery could challenge our theories of how gas giants like Jupiter form.

Astronomers have discovered an unusual planetary system consisting of a Jupiter-sized planet orbiting a tiny star that is only four times the size of the solar system gas giant. This "forbidden" configuration of a massive planet orbiting a relatively tiny star could challenge theories of how gas giant planets form.

The extrasolar planet, or "exoplanet," orbits a red dwarf star designated TOI 5205 that is much cooler and smaller than the sun. The small size and relatively cool temperatures of these M-dwarf stars, the most common type of stellar body in the Milky Way, make them redder than the sun.

Though on average this class of stars hosts more planets around them than other star types, it was previously believed that their formation makes them unlikely to be orbited by gas giants. The discovery of this exoplanet  —  designated TOI 5205b  —  by astronomers using NASA's Transiting Exoplanet Survey Satellite (TESS) telescope challenges that concept. The planet was confirmed and characterized by the team using various ground-based telescopes and instruments.

https://www.space.com/forbidden-planet- ... -tiny-star

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The First Circumbinary Planet Discovered With Radial Velocities
By Keith Cowing
https://astrobiology.com/2023/02/the-fi ... ities.html
February 26, 2023

The First Circumbinary Planet Discovered With Radial Velocities
Overview of the TOI-1338/BEBOP-1 system along with the extent of the systems habitable zone calculated using the Multiple Star HZ website (45). The conservative habitable zone is shown by the dark green region, while the optimistic habitable zone is shown by the light green region. Binary stars are marked by the blue stars in the centre. TOI-1338/BEBOP-1c’s orbit is shown by the red orbit models, based on 500 randomly drawn posterior samples from a kima run, shaded from the 50th to 99th percentiles. TOI-1338/BEBOP-1b’s orbit is shown by the yellow models, and is also based on 500 random samples drawn from the posterior in its discovery paper (17). — astro-ph.EP

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The TESS Triple-9 Catalog II: a new set of 999 uniformly-vetted exoplanet candidates
https://arxiv.org/abs/2303.00624

Twelve the most significant validated planet candidates: TOI-161, 277*, 1086, 1107, 1163, 1186, 1272*, 1274, 1302, 1482, 1845 and 2659.

* Already confirmed and listed exoplanet hosts.

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GAIA mission been extended until middle of 2025 it will be 11 years of scientific mission until there maybe 100,000 planets until the end of processing the data in 2030 who knows…

https://sci.esa.int/web/director-desk/- ... e-missions

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A super-Earth and a mini-Neptune near the 2:1 MMR straddling the radius valley around the nearby mid-M dwarf TOI-2096
https://arxiv.org/abs/2303.08174

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Small stars may host bigger planets than previously thought
https://phys.org/news/2023-03-small-sta ... anets.html
by University College London

Stars with less than half the mass of our sun are able to host giant Jupiter-style planets, in conflict with the most widely accepted theory of how such planets form, according to a new study led by UCL (University College London) and University of Warwick researchers.

Gas giants, like other planets, form from disks of material surrounding young stars. According to core accretion theory, they first form a core of rock, ice and other heavy solids, attracting an outer layer of gas once this core is sufficiently massive (about 15 to 20 times that of Earth).

However, low-mass stars have low-mass disks that, models predict, would not provide enough material to form a gas giant in this way, or at least not quickly enough before the disk breaks up.

In the study, accepted for publication in the Monthly Notices of the Royal Astronomical Society (MNRAS), researchers looked at 91,306 low-mass stars, using observations from NASA's Transiting Exoplanet Survey Satellite (TESS), and in 15 cases found dips in the brightness of the light corresponding to a gas giant passing in front of the star.

Five out of the 15 potential giant planets have since been confirmed as planets using independent methods. One of these confirmed planets orbits a star that is a fifth of the mass of the sun—which would not be possible according to planet formation models.

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James Webb telescope detects dust storm on distant world
https://www.bbc.com/news/science-environment-65040983

A raging dust storm has been observed on a planet outside our Solar System for the first time.

It was detected on the exoplanet known as VHS 1256b, which is about 40 light-years from Earth.

It took the remarkable capabilities of the new James Webb Space Telescope (JWST) to make the discovery.

The dust particles are silicates - small grains comprising silicon and oxygen, which form the basis of most rocky minerals.

But the storm detected by Webb isn't quite the same phenomenon you would get in an arid, desert region on our planet. It's more of a rocky mist.

"It's kind of like if you took sand grains, but much finer. We're talking silicate grains the size of smoke particles," explained Prof Beth Biller from the University of Edinburgh and the Royal Observatory Edinburgh, UK.

"That's what the clouds on VHS 1256b would be like, but a lot hotter. This planet is a hot, young object. The cloud-top temperature is maybe similar to the temperature of a candle flame," she told BBC News.

[wjfox]

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Webb space telescope measures the temperature of a rocky exoplanet
https://phys.org/news/2023-03-webb-spac ... rocky.html
by European Space Agency

An international team of researchers has used the NASA/ESA/CSA James Webb Space Telescope to measure the temperature of the rocky exoplanet TRAPPIST-1 b. The measurement is based on the planet's thermal emission: heat energy given off in the form of infrared light detected by Webb's Mid-Infrared Instrument (MIRI).

The result indicates that the planet's dayside has a temperature of about 500 Kelvin (roughly 230°C), and suggests that it has no significant atmosphere. This is the first detection of any form of light emitted by an exoplanet as small and as cool as the rocky planets in our own solar system. The result marks an important step in determining whether planets orbiting small active stars like TRAPPIST-1 can sustain atmospheres needed to support life. It also bodes well for Webb's ability to characterize temperate, Earth-sized exoplanets using MIRI.

"These observations really take advantage of Webb's mid-infrared capability," said Thomas Greene, an astrophysicist at NASA's Ames Research Center and lead author on the study published today in the journal Nature. "No previous telescopes have had the sensitivity to measure such dim mid-infrared light."

[Time_Traveller]

Discovering the Most Terrifying Planets in the Universe (VIDEO)

March 30, 2023

Have you ever looked up at the night sky and wondered what kind of planets are oᴜt there? Well, let me tell you, not all of them are the idyllic, habitable worlds we dream of. In fact, some of the planets we’ve discovered are downright teггіfуіпɡ. From never-ending nights to raining glass and planets being devoured by their own stars, the universe is full of surprises – and not all of them are pleasant.

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Repeating Radio Signal Leads Astronomers to an Earth-size Exoplanet
Source: CNN

Astronomers have detected a repeating radio signal from an exoplanet and the star that it orbits, both located 12 light-years away from Earth. The signal suggests that the Earth-size planet may have a magnetic field and perhaps even an atmosphere.

Earth’s magnetic field protects the planet’s atmosphere, which life needs to survive, by deflecting energetic particles and plasma that stream out from the sun. Finding atmospheres around planets located outside of our solar system could point to other worlds that potentially have the ability to support life.

Scientists noticed strong radio waves coming from the star YZ Ceti and the rocky exoplanet that orbits it, called YZ Ceti b, during observations using the Karl G. Jansky Very Large Array of telescopes in New Mexico. The researchers believe the radio signal was created by interactions between the planet’s magnetic field and the star.

A study detailing the findings was published Monday in the journal Nature Astronomy.

Read more: https://www.cnn.com/2023/04/04/world/ex ... index.html

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Coherent radio bursts from known M-dwarf planet-host YZ Ceti
https://www.nature.com/articles/s41550- ... tastronTWT

Conclusions wrote:

Using simple Poisson statistics, the probability of seeing at least one event in the 3.6 h associated with epoch 5 is ~24%. By contrast, the probability of seeing one burst, on two separate occasions within 2 h of a given phase (a 4 h window) is only 5.1%—small but insufficient as conclusive evidence. It is thus plausible that the bursts could have no association with the planetary system and be a normal part of the radio stellar activity of slowly rotating M dwarfs, which is not yet well studied. The mechanisms powering the emission remain inconclusive, and we thus categorize YZ Cet as an SPI candidate, requiring further follow-up to discern the nature of the radio bursts.

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LHS 475 b: A Venus-sized Planet Orbiting a Nearby M Dwarf
https://arxiv.org/abs/2304.01920
Quote :

Based on photometric observations by TESS, we present the discovery of a Venus-sized planet transiting LHS 475, an M3 dwarf located 12.5 pc from the Sun. The mass of the star is 0.274±0.015 MSun. The planet, originally reported as TOI 910.01, has an orbital period of 2.0291025±0.0000020 days and an estimated radius of 0.955±0.053 REarth. We confirm the validity and source of the transit signal with MEarth ground-based follow-up photometry of five individual transits. We present radial velocity data from CHIRON that rule out massive companions. In accordance with the observed mass-radius distribution of exoplanets as well as planet formation theory, we expect this Venus-sized companion to be terrestrial, with an estimated RV semi-amplitude close to 1.0 m/s. LHS 475 b is likely too hot to be habitable but is a suitable candidate for emission and transmission spectroscopy.