Exoplanets – worlds of other suns

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Super-Precise NEID Spectrograph Spots Its First New Planet
HD 86728 b is nine times Earth's mass and may be the only world in its solar system.
By Ryan Whitwam September 30, 2024

Astronomers have a new way to hunt for exoplanets today. The team behind the NEID Earth Twin Survey (NETS) project has published a paper detailing their first planetary discovery. The newly confirmed exoplanet orbits a star called HD 86728, about 48 light-years away. For now, this world appears to be the only planet orbiting the star, making it quite unusual.

NEID is not a telescope, but it's installed on one. As part of the 3.5-meter WIYN telescope at Kitt Peak National Observatory in Arizona, this powerful echelle-type spectrograph can separate and analyze the infrared spectrum of a distant object with high precision. Despite the formatting and tendency for astronomical tools to stand for something, NEID is not an acronym. It's derived from the term "to see" in the native Tohono O’odham language.

https://www.extremetech.com/science/sup ... new-planet

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Scientists discover planet orbiting closest single star to our Sun

https://www.eso.org/public/news/eso2414/

A sub-Earth-mass planet orbiting Barnard’s star

https://www.eso.org/public/archives/rel ... o2414a.pdf

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New super-Neptune exoplanet discovered
https://phys.org/news/2024-10-super-nep ... lanet.html
by Tomasz Nowakowski , Phys.org

An international team of astronomers reports the discovery of a new super-Neptune exoplanet orbiting a solar-type star. The newly detected alien world, which received the designation TOI-5005 b, is about six times larger and more than 30 times more massive than Earth. The finding was detailed in a paper published September 26 on the pre-print server arXiv.

NASA's Transiting Exoplanets Survey Satellite (TESS) is conducting a survey of about 200,000 of the brightest stars near the sun with the aim of searching for transiting exoplanets. So far, it has identified over 7,200 candidate exoplanets (TESS Objects of Interest, or TOI), of which 557 have been confirmed so far.

Recently, a group of astronomers led by Amadeo Castro-González of the Astrobiology Center in Madrid, Spain, confirmed another TOI monitored by TESS. They found a transit signal on the light curve of TOI-5005—a moderately bright solar-type star of spectral type G2V, located some 685 light years away. The planetary nature of this signal was confirmed by follow-up observations using ground-based facilities.

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A Fourth Planet in the Kepler-51 System Revealed by Transit Timing Variations
https://arxiv.org/abs/2410.01625

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Distant planet may host volcanic moon like Jupiter's Io
https://phys.org/news/2024-10-distant-p ... -moon.html
by Calla Cofield, NASA

New research done at NASA's Jet Propulsion Laboratory reveals potential signs of a rocky, volcanic moon orbiting an exoplanet 635 light-years from Earth. The biggest clue is a sodium cloud that the findings suggest is close to but slightly out of sync with the exoplanet, a Saturn-size gas giant named WASP-49 b, although additional research is needed to confirm the cloud's behavior. Within our solar system, gas emissions from Jupiter's volcanic moon Io create a similar phenomenon.

Although no exomoons (moons of planets outside our solar system) have been confirmed, multiple candidates have been identified. It's likely these planetary companions have gone undetected because they are too small and dim for current telescopes to detect.

The sodium cloud around WASP-49 b was first detected in 2017, catching the attention of Apurva Oza, formerly a postdoctoral researcher at NASA's Jet Propulsion Laboratory and now a staff scientist at Caltech, which manages JPL. Oza has spent years investigating how exomoons might be detected via their volcanic activity.

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Webb Telescope Spots Evidence of a Distant, Water-Rich 'Steam World'
It's the first time the long-hypothesized water vapor-rich exoplanet has been found.
By Adrianna Nine October 14, 2024
https://www.extremetech.com/science/web ... team-world

The James Webb Space Telescope has spotted something steamy. No, not that kind of steamy. Using its spectroscopic instruments, the observatory has found evidence that a distant exoplanet's atmosphere could be chock-full of water in its gaseous state. If Webb is on the right track, its findings will represent the first-ever discovery of a so-called "steam world" outside of the solar system.

In a paper for The Astrophysical Journal Letters, an international team of researchers describes the atmospheric composition of GJ 9827 d, a sub-Neptune exoplanet nearly 100 light-years away from Earth. GJ 9827 d itself isn't a new discovery; NASA's Kepler space telescope found it back in 2017. After the agency worked with the European Space Agency (ESA) and the Canadian Space Agency (CSA) to launch Webb, however, NASA unlocked troves of data via Webb's spectroscopy instruments—namely its Near Infrared Imager and Slitless Spectrograph (NIRISS) and Near Infrared Spectrograph (NIRSpec).

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A Planet Candidate Orbiting near the Hot Jupiter TOI-2818 b Inferred through Transit Timing

https://arxiv.org/abs/2411.04192

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New solar composition ratios that could reconcile longstanding questions

November 12, 2024

A Southwest Research Institute-led team combined compositional data of primitive bodies like Kuiper Belt objects, asteroids and comets with new solar data sets to develop a revised solar composition that potentially reconciles spectroscopy and helioseismology measurements for the first time. Helioseismology probes the Sun's interior by analyzing the waves that travel through it, while spectroscopy reveals the surface composition based on the spectral signature produced by each chemical element.

A paper about this research, which addresses the long-standing "solar abundances" problem, appears in the AAS Astrophysical Journal.

"This is the first time this kind of interdisciplinary analysis has been done, and our broad data set suggests more abundant levels of solar carbon, nitrogen and oxygen than previously thought," said Dr. Ngoc Truong, an SwRI postdoctoral researcher. "Solar system formation models using the new solar composition successfully reproduce the compositions of large Kuiper Belt objects (KBOs) and carbonaceous chondrite meteorites, in light of the newly returned Ryugu and Bennu asteroid samples from JAXA's Hayabusa-2 and NASA's OSIRIS-REx missions."

To make this discovery, the team combined new measurements of solar neutrinos and data about the solar wind composition from NASA's Genesis mission, together with the abundance of water found in primitive meteorites that originated in the outer solar system. They also used the densities of large KBOs such as Pluto and its moon Charon, as determined by NASA's New Horizons mission.

"This work provides testable predictions for future helioseismology, solar neutrino and cosmochemical measurements, including future comet sample return missions," Truong said. "The solar composition is used to calibrate other stars and understand the composition and formation of solar system objects. These breakthroughs will enhance our understanding of the primordial solar nebula's chemistry and the formation of numerous solar system bodies."

https://www.sciencedaily.com/releases/2 ... 122742.htm

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Gl 725A b: a potential super-Earth detected with SOPHIE and SPIRou in an M dwarf binary system at 3.5 pc Gl 725A b: a potential super-Earth detected with SOPHIE and SPIRou in an M dwarf binary system at 3.5 pc

We report the discovery of a super-Earth candidate orbiting the nearby mid M dwarf Gl\,725A using the radial velocity (RV) method. The planetary signal has been independently identified using high-precision RVs from the SOPHIE and SPIRou spectrographs, in the optical and near-infrared domains, respectively. We modelled the stellar activity signal jointly with the planet using two Gaussian Processes, one for each instrument to account for the chromaticity of the stellar activity and instrumental systematics, along with a Keplerian model. The signal is significantly detected with a RV semi-amplitude of 1.67±0.20 m/s. The planet Gl 725A b is found to be in an orbit compatible with circular with a period of 11.2201±0.0051 days. We analysed 27 sectors of TESS photometry on which no transit event was found. We determined a minimum mass of Mpsini=2.78±0.35M⊕ which places the planet in the super-Earth regime. Using Mass-Radius relationships we predict a planetary radius to be between 1.2 and 2.0R⊕. The proximity of Gl 725A, of only 3.5 pc, makes this new exoplanet one of the closest to Earth and joins the group of S-type low-mass planets in short orbits (P<15 d) around close M dwarfs

https://arxiv.org/abs/2411.09506

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Astrophysicist Glimpses 'Newborn' Transiting Exoplanet
The young and distant object offers researchers a never-before-seek peek at the early stages of a planet's life.
By Adrianna Nine November 27, 2024

An astrophysicist-in-training has found the youngest transiting exoplanet ever observed. Her discovery offers an unprecedented real-time peek at the earliest stages of a planet's existence—"early" in this case meaning just 3 million years old.

Madyson Barber, a graduate student of astrophysics at the University of North Carolina at Chapel Hill, had already discovered two previous exoplanets when she spotted the newborn transiting system. Like others in the field, though, she had only been able to locate mature planets ranging from 10 million to 40 million years old. This is because young solar systems contain protoplanetary disks, or rings of gas, dust, and other material that block even the most advanced observational equipment from seeing what lies beyond. As the material in the disk fuses to create celestial bodies, the disk disappears. This usually occurs around the solar system's 10 millionth birthday.

https://www.extremetech.com/science/ast ... -exoplanet

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A Fourth Planet in the Kepler-51 System Revealed by Transit Timing Variations

https://iopscience.iop.org/article/10.3 ... 881/ad83d3

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Two Earth-sized exoplanets orbiting nearby star detected
https://phys.org/news/2024-12-earth-siz ... earby.html
by Tomasz Nowakowski , Phys.org

An international team of astronomers has reported the discovery of two exoplanets orbiting a nearby star known as HD 101581. The newfound alien worlds are slightly smaller than Earth and orbit its host very closely. The discovery was detailed in a paper published Dec. 12 on the pre-print server arXiv.

NASA's Transiting Exoplanet Survey Satellite (TESS) has identified more than 7,300 candidate exoplanets (TESS Objects of Interest, or TOI), of which 589 have been confirmed so far. Since its launch in April 2018, the satellite has been conducting a survey of about 200,000 of the brightest stars near the sun with the aim of searching for transiting exoplanets.

A recent study published by a group of astronomers led by Michelle Kunimoto of the Massachusetts Institute of Technology (MIT) has confirmed the planetary nature of two TOIs. The team reports that transit signals identified by TESS in the light curve of TOI-6276, or HD 101581, are caused by two Earth-sized extrasolar worlds.

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Could habitable planets orbiting white dwarfs retain their oceans? Maybe
https://phys.org/news/2025-01-habitable ... warfs.html
by Brian Koberlein, Universe

Potentially habitable exoplanets are so incredibly common that astronomers have started to consider more unusual situations where life might arise. Perhaps life can be found on the moon of a hot Jupiter or lingering in the warm ocean of a rogue planet. Recently, there has even been the idea that habitable worlds might orbit white dwarfs.

We know some white dwarfs have planets, and despite lacking nuclear fusion, white dwarfs do emit enough light and heat to have a habitable zone. But the question remains as to whether a planet could retain a water-rich environment through the red giant stage of a star before it becomes a white dwarf. This is the focus of a new study posted to the arXiv preprint server.

The study starts by stating the obvious. Any habitable world around a main-sequence star will likely be stripped of its atmosphere and water as the star swells to a red giant. By the time the star becomes a white dwarf, any planet that was habitable will be barren, if not consumed by its star. The work then goes on to consider more distant worlds in a system. Perhaps a cold and icy Hycean world might become habitable in the white dwarf stage.

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Water and carbon dioxide detected in the atmosphere of a hot super-Neptune exoplanet
https://phys.org/news/2025-01-carbon-di ... super.html
by Tomasz Nowakowski , Phys.org

Using the James Webb Space Telescope (JWST), astronomers have characterized the atmosphere of a hot super-Neptune exoplanet designated WASP-166 b. As a result, they found that the atmosphere of this alien world contains water and carbon dioxide. Their findings were reported Dec. 31 on the arXiv preprint server.

WASP-166 b is about seven times larger and 32 times more massive than the Earth. It orbits its host star every 5.44 days, at a distance of approximately 0.067 AU from it. The planet is relatively hot as its equilibrium temperature is estimated to be 1,270 K. The parameters of WASP-166 make it a representative of the so-called hot Neptune desert—a region of parameter space at high insolation fluxes and intermediate planet radii that is very sparsely populated.

The parent star WASP-166, which is located some 368 light years away, has a spectral type of F9V, and is about 20% larger and more massive than the sun. The star has an effective temperature of 6,050 K, metallicity at a level of 0.19 dex, and its age is estimated to be 2.1 billion years.

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For more background information: https://www.universetoday.com/170469/na ... ospheres/

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Astronomers Discover Supersonic Winds Wrapped Around Distant Planet
WASP-127b's equatorial winds whip around the gas giant at an estimated 20,505 miles per hour.
By Adrianna Nine January 27, 2025

When astronomers first spotted WASP-127b in 2016, the exoplanet's strange composition intrigued them. With a radius larger than Jupiter's but less than a fifth of the planet's mass, WASP-127b possesses a highly inflated atmosphere—one scientists have since referred to as "puffy." But the distant gas giant's puffed-up format is no longer its most interesting trait. Astronomers using the European Southern Observatory's Very Large Telescope (VLT) have found that WASP-127b is wrapped in supersonic winds, which whip around its equator at an estimated 33,000 kilometers (20,505 miles) per hour.

https://www.extremetech.com/science/ast ... ant-planet

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Exoplanets Seen Falling Apart
by Evan Gough
January 27, 2025

Introduction:

(Universe Today) Astronomers have found two planets around two separate stars that are succumbing to their stars’ intense heat. Both are disintegrating before our telescopic eyes, leaving trails of debris similar to a comet’s. Both are ultra-short-period planets (USPs) that orbit their stars rapidly.

These planets are a rare sub-class of USPs that are not massive enough to hold onto their material. Astronomers know of only three other disintegrating planets.

Fortunately, two separate teams of researchers have spotted the two disintegrating USPs. As they spill their contents out into space in tails, they’re giving astronomers an opportunity to see what’s inside them

Read more of the Eurekalert article here: https://www.universetoday.com/170626/e ... e-170626

For a presentation of study results as published at the arxiv.org site https://arxiv.org/pdf/2501.05431

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Super-Earth discovery reveals an exoplanet potentially capable of sustaining life

by University of Geneva
https://phys.org/news/2025-01-super-ear ... lanet.html

Thirty years after the discovery of the first exoplanet, astronomers have detected more than 7,000 of them in our galaxy. But there are still billions more to be discovered. At the same time, exoplanetologists have begun to take an interest in their characteristics, with the aim of finding life elsewhere in the universe. This is the background to the discovery of super-Earth HD 20794 d by an international team including the University of Geneva (UNIGE) and the NCCR PlanetS.

The new planet lies in an eccentric orbit, so that it oscillates in and out of its star's habitable zone. This discovery is the fruit of 20 years of observations using the best telescopes in the world. The results are published in the journal Astronomy & Astrophysics.

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Scientists spot candidate for speediest exoplanet system
https://phys.org/news/2025-02-scientist ... lanet.html
by Ashley Balzer, NASA

Astronomers may have discovered a scrawny star bolting through the middle of our galaxy with a planet in tow. If confirmed, the pair sets a new record for the fastest-moving exoplanet system, nearly double our solar system's speed through the Milky Way.

The planetary system is thought to move at least 1.2 million miles per hour, or 540 kilometers per second.

"We think this is a so-called super-Neptune world orbiting a low-mass star at a distance that would lie between the orbits of Venus and Earth if it were in our solar system," said Sean Terry, a postdoctoral researcher at the University of Maryland, College Park and NASA's Goddard Space Flight Center in Greenbelt, Maryland. Since the star is so feeble, that's well outside its habitable zone. "If so, it will be the first planet ever found orbiting a hypervelocity star."