Exoplanets – worlds of other suns

User avatar
wjfox
Site Admin
Posts: 8730
Joined: Sat May 15, 2021 6:09 pm
Location: London, UK
Contact:

Re: Exoplanets – worlds of other suns

Post by wjfox »

Discovery Alert: Two New, Rocky Planets in the Solar Neighborhood

June 15, 2022

The discovery: NASA’s TESS mission has found two rocky worlds orbiting the relatively bright, red dwarf star HD 260655, only 33 light-years away. The new planets, HD 260655 b and HD 260655 c, are among the closest-known rocky planets yet found outside our solar system that astronomers can observe crossing the faces of their stars.

Key facts: Using NASA’s orbiting planet hunter, the Transiting Exoplanet Survey Satellite (TESS), scientists discovered sibling planets in Earth’s size-range that are prime candidates for atmospheric investigation. And the discovery comes at an ideal moment: The giant James Webb Space Telescope, soon to deliver its first science images, can examine the atmospheres of exoplanets – planets beyond our solar system – to search for water, carbon molecules and other components. Learning more about the atmospheres of rocky planets will help scientists understand the formation and development of worlds like our own.

Details: Both planets are “super-Earths” – terrestrial worlds like ours, only bigger. Planet b is about 1.2 times as big around as Earth, planet c 1.5 times. In this case, however, neither world is likely to support life. The temperature on planet b, nearest to the star, is estimated at 816 degrees Fahrenheit (435 Celsius), planet c 543 Fahrenheit (284 Celsius), though actual temperature depends on the presence and nature of possible atmospheres.

Still, the science team that discovered the planets says they are well worth further investigation. At 33 light-years, they are relatively close to us, and their star, though smaller than ours, is among the brightest in its class. These and other factors raise the likelihood that the Webb telescope, and perhaps even the Hubble Space Telescope, could capture data from the star’s light shining through these planets’ atmospheres. Such light can be spread into a spectrum, revealing the fingerprints of molecules within the atmosphere itself.

Both planets rate in the top 10 candidates for atmospheric characterization among all terrestrial exoplanets so far discovered, the team says. That places them in the same category as one of the most famous planetary systems: the seven roughly Earth-sized planets around a star called TRAPPIST-1. The TRAPPIST-1 worlds and several other rocky exoplanets are already on the list of observation targets for the Webb telescope.

https://exoplanets.nasa.gov/news/1706/d ... ghborhood/


Image
weatheriscool
Posts: 12946
Joined: Sun May 16, 2021 6:16 pm

Re: Exoplanets – worlds of other suns

Post by weatheriscool »

Kepler-1928 b...
https://arxiv.org/abs/2206.08383
Transit Hunt for Young and Maturing Exoplanets (THYME) VIII: a Pleiades-age association harboring two transiting planetary systems from Kepler
Young planets provide a window into the early stages and evolution of planetary systems. Ideal planets for such research are in coeval associations, where the parent population can precisely determine their ages. We describe a young association (MELANGE-3) in the Kepler field, which harbors two transiting planetary systems (Kepler-1928 and Kepler-970). We identify MELANGE-3 by searching for kinematic and spatial overdensities around Kepler planet hosts with high levels of lithium. To determine the age and membership of MELANGE-3, we combine new high-resolution spectra with archival light curves, velocities, and astrometry of stars near Kepler-1928 spatially and kinematically. We use the resulting rotation sequence, lithium levels, and color-magnitude diagram of candidate members to confirm the presence of a coeval 105±10 Myr population. MELANGE-3 may be part of the recently identified Theia 316 stream. For the two exoplanet systems, we revise the stellar and planetary parameters, taking into account the newly-determined age. Fitting the 4.5 yr Kepler light curves, we find that Kepler-1928 b is a 2.0±0.1R⊕ planet on a 19.58-day orbit, while Kepler-970 b is a 2.8±0.2R⊕ planet on a 16.73-day orbit. Kepler-1928 was previously flagged as an eclipsing binary, which we rule out using radial velocities from APOGEE and statistically validate the signal as planetary in origin. Given its overlap with the Kepler field, MELANGE-3 is valuable for studies of spot evolution on year timescales, and both planets contribute to the growing work on transiting planets in young stellar associations.
User avatar
caltrek
Posts: 6509
Joined: Mon May 17, 2021 1:17 pm

Re: Exoplanets – worlds of other suns

Post by caltrek »

I suppose that the following article fits this thread, although you might need to think of the exoplanets in the past tense. Even then, exoplanets are just one possible explanation of the observed events.

A Strange White Dwarf With a Chaotic Past
by Govert Schilling
June 16, 2022

Introduction:
(Sky & Telescope) What’s stranger than stones raining down onto a hot white dwarf star? Adding chunks of ice to the mix.

G238-44, a puny white dwarf at a distance of 86 light-years, is accreting two very different kind of objects simultaneously, Ted Johnson (University of California, Los Angeles) told the 240th meeting of the American Astronomical Society in Pasadena, California, on Wednesday. “This has never been observed before,” he says.

White dwarfs are the compact remains of low-mass stars that first balloon into red giants — a fate that awaits our own Sun some 5 billion years from now. The red giant phase wreaks havoc with orderly planetary systems. Close-in planets may be devoured, while the orbits of more distant worlds become jumbled.

After the giant star blows away its outer layers into a planetary nebula, a roughly Earth-size (but still solar mass) white dwarf remains. Observations of many white dwarfs show signs of atmospheric “pollution”: unexpected amounts of elements heavier than helium. Their existence indicates that when collisions disrupt the orbits of asteroid-like bodies in the white dwarf system, their rocky debris rains down onto the star.

So what’s so strange about G238-44? It’s the chemical composition of the pollution on its surface, as measured by NASA’s Far Ultraviolet Spectroscopic Explorer (FUSE), the Keck Telescope in Hawai’i, and the Hubble Space Telescope. The relative abundances of 10 heavy elements (carbon, nitrogen, oxygen, magnesium, aluminum, silicon, phosphorus, sulfur, calcium, and iron) don’t match the composition of any known solar system object.
Read more here: https://skyandtelescope.org/astronomy- ... aotic-past
Don't mourn, organize.

-Joe Hill
weatheriscool
Posts: 12946
Joined: Sun May 16, 2021 6:16 pm

Re: Exoplanets – worlds of other suns

Post by weatheriscool »

Long-term liquid water also on non-Earth-like planets?
https://phys.org/news/2022-06-long-term ... anets.html
by University of Bern
Life on Earth began in the oceans. In the search for life on other planets, the potential for liquid water is therefore a key ingredient. To find it, scientists have traditionally looked for planets similar to our own. Yet, long-term liquid water does not necessarily have to occur under similar circumstances as on Earth. Researchers of the University of Bern and the University of Zurich, who are members of the National Centre of Competence in Research (NCCR) PlanetS, report in a study published in the journal Nature Astronomy, that favorable conditions might even occur for billions of years on planets that barely resemble our home planet at all.

Primordial greenhouses

"One of the reasons that water can be liquid on Earth is its atmosphere," study co-author Ravit Helled, Professor of Theoretical Astrophysics at the University of Zurich and a member of the NCCR PlanetS explains. "With its natural greenhouse effect, it traps just the right amount of heat to create the right conditions for oceans, rivers and rain," says the researcher.

Earth's atmosphere used to be very different in its ancient history, however. "When the planet first formed out of cosmic gas and dust, it collected an atmosphere consisting mostly of Hydrogen and Helium—a so-called primordial atmosphere," Helled points out. Over the course of its development, however, Earth lost this primordial atmosphere.
weatheriscool
Posts: 12946
Joined: Sun May 16, 2021 6:16 pm

Re: Exoplanets – worlds of other suns

Post by weatheriscool »

Update on the possible directly imaged planet candidate at Alpha Cen A. Not confirmation, but an independent analysis of the data also detects it.

Efficiently combining Alpha CenA multi-epoch high-contrast imaging data. Application of K-Stacker to the 80 hrs NEAR campaign
https://arxiv.org/abs/2207.02137
weatheriscool
Posts: 12946
Joined: Sun May 16, 2021 6:16 pm

Re: Exoplanets – worlds of other suns

Post by weatheriscool »

There's a program with JWST+MIRI coming soon, may be a planet will be confirmed ?

https://www.stsci.edu/jwst/phase2-public/1618.pdf
weatheriscool
Posts: 12946
Joined: Sun May 16, 2021 6:16 pm

Re: Exoplanets – worlds of other suns

Post by weatheriscool »

NASA helps decipher how some distant planets have clouds of sand
Image
by Jet Propulsion Laboratory
https://phys.org/news/2022-07-nasa-deci ... louds.html
Most clouds on Earth are made of water, but beyond our planet they come in many chemical varieties. The top of Jupiter's atmosphere, for example, is blanketed in yellow-hued clouds made of ammonia and ammonium hydrosulfide. And on worlds outside our solar system, there are clouds composed of silicates, the family of rock-forming minerals that make up over 90% of Earth's crust. But researchers haven't been able to observe the conditions under which these clouds of small dust grains form.

A new study appearing in the Monthly Notices of the Royal Astronomical Society provides some insight: The research reveals the temperature range at which silicate clouds can form and are visible at the top of a distant planet's atmosphere. The finding was derived from observations by NASA's retired Spitzer Space Telescope of brown dwarfs—celestial bodies that fall in between planets and stars—but it fits into a more general understanding of how planetary atmospheres work.
Last edited by weatheriscool on Fri Jul 15, 2022 7:02 am, edited 1 time in total.
weatheriscool
Posts: 12946
Joined: Sun May 16, 2021 6:16 pm

Re: Exoplanets – worlds of other suns

Post by weatheriscool »

Webb reveals steamy atmosphere of distant planet in detail
https://phys.org/news/2022-07-webb-reve ... stant.html

Image
by NASA

NASA's James Webb Space Telescope has captured the distinct signature of water, along with evidence for clouds and haze, in the atmosphere surrounding a hot, puffy gas giant planet orbiting a distant Sun-like star.

The observation, which reveals the presence of specific gas molecules based on tiny decreases in the brightness of precise colors of light, is the most detailed of its kind to date, demonstrating Webb's unprecedented ability to analyze atmospheres hundreds of light-years away.

While the Hubble Space Telescope has analyzed numerous exoplanet atmospheres over the past two decades, capturing the first clear detection of water in 2013, Webb's immediate and more detailed observation marks a giant leap forward in the quest to characterize potentially habitable planets beyond Earth.

WASP-96 b is one of more than 5,000 confirmed exoplanets in the Milky Way. Located roughly 1,150 light-years away in the southern-sky constellation Phoenix, it represents a type of gas giant that has no direct analog in our solar system. With a mass less than half that of Jupiter and a diameter 1.2 times greater, WASP-96 b is much puffier than any planet orbiting our Sun. And with a temperature greater than 1000°F, it is significantly hotter. WASP-96 b orbits extremely close to its Sun-like star, just one-ninth of the distance between Mercury and the Sun, completing one circuit every 3½ Earth-days.
User avatar
wjfox
Site Admin
Posts: 8730
Joined: Sat May 15, 2021 6:09 pm
Location: London, UK
Contact:

Re: Exoplanets – worlds of other suns

Post by wjfox »

User avatar
caltrek
Posts: 6509
Joined: Mon May 17, 2021 1:17 pm

Re: Exoplanets – worlds of other suns

Post by caltrek »

The Webb Telescope’s Search for Life in Space May take Longer than Expected
by Georgina Torbet
July 16, 2022

Introduction:
(Inverse) ONE OF THE AIMS of the James Webb Space Telescope is a profound one: To search for habitable exoplanets, where one day we could look for evidence of life beyond our own planet. But habitability is no simple matter, and finding another “Earth-like” planet might be more complicated than you imagine.

Around 40 light years away lies a remarkable star system. The TRAPPIST-1 system became world-famous five years ago when NASA announced it and several partners had discovered a whole bevy of Earth-sized planets orbiting within the habitable zone of a single star. Since then, astronomers have been desperate to learn more about these nearby worlds which could be like our planet.

Enter the James Webb Space Telescope, which will investigate the TRAPPIST-1 system in its first cycle of research programs. The research will aim to see if the planets in the TRAPPIST-1 system have atmospheres and, in the long term, to set up the process of looking for biosignatures that could indicate if life were present on any of the planets.

But there are many challenges when it comes to understanding worlds that are different from ours. Recent modeling work shows that it isn’t just a planet’s distance from its star or its composition that affects its climate: The distribution of land across a planet’s surface also significantly impacts its potential habitability.
Read more here: https://www.inverse.com/science/jwst- ... ntauri-b
Don't mourn, organize.

-Joe Hill
Post Reply