Exoplanets – worlds of other suns

weatheriscool
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Re: Exoplanets – worlds of other suns

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Kepler telescope delivers new planetary discovery from the grave
https://phys.org/news/2022-04-kepler-te ... grave.html
by Jodrell Bank Centre for Astrophysics
A new study by an international team of astrophysicists, led by the Jodrell Bank Center for Astrophysics has presented the amazing new discovery of a near-identical twin of Jupiter orbiting a star at a colossal distance of 17,000 light years from Earth.

The exoplanet, K2-2016-BLG-0005Lb, is almost identical to Jupiter in terms of its mass and distance from the sun, was discovered using data obtained in 2016 by NASA's Kepler space telescope. The exoplanetary system is twice as distant as any seen previously by Kepler, which found over 2,700 confirmed planets before ceasing operations in 2018.

The system was found using gravitational microlensing, a prediction of Einstein's Theory of Relativity, and is the first planet to be discovered from space in this way. The study has been submitted to the journal Monthly Notices of the Royal Astronomical Society and has been made available as a preprint on ArXiv.org.

Ph.D. student, David Specht from The University of Manchester is the lead author on the new research. To find an exoplanet using the microlensing effect the team searched through Kepler data collected between April and July 2016 when it regularly monitored millions of stars close to the center of the Galaxy. The aim was to look for evidence of an exoplanet and its host star temporarily bending and magnifying the light from a background star as it passes by the line of sight.
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caltrek
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Re: Exoplanets – worlds of other suns

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Hubble Probes Extreme Weather on Ultra-hot Jupiters
April 6, 2022

https://www.eurekalert.org/news-releases/948943

Introduction:
(EurekAlert) In studying a unique class of ultra-hot exoplanets, NASA Hubble Space Telescope astronomers may be in the mood for dancing to the Calypso party song "Hot, Hot, Hot." That's because these bloated Jupiter-sized worlds are so precariously close to their parent star they are being roasted at seething temperatures above 3,000 degrees Fahrenheit. That's hot enough to vaporize most metals, including titanium. They have the hottest planetary atmospheres ever seen.

In two new papers, teams of Hubble astronomers are reporting on bizarre weather conditions on these sizzling worlds. It's raining vaporized rock on one planet, and another one has its upper atmosphere getting hotter rather than cooler because it is being "sunburned" by intense ultraviolet (UV) radiation from its star.

This research goes beyond simply finding weird and quirky planet atmospheres. Studying extreme weather gives astronomers better insights into the diversity, complexity, and exotic chemistry taking place in far-flung worlds across our galaxy.

"We still don't have a good understanding of weather in different planetary environments," said David Sing of the Johns Hopkins University in Baltimore, Maryland, co-author on two studies being reported. "When you look at Earth, all our weather predictions are still finely tuned to what we can measure. But when you go to a distant exoplanet, you have limited predictive powers because you haven't built a general theory about how everything in an atmosphere goes together and responds to extreme conditions. Even though you know the basic chemistry and physics, you don't know how it's going to manifest in complex ways."

In a paper in the April 7 journal Nature, astronomers describe Hubble observations of WASP-178b, located about 1,300 light-years away. On the daytime side the atmosphere is cloudless, and is enriched in silicon monoxide gas. Because one side of the planet permanently faces its star, the torrid atmosphere whips around to the nighttime side at super-hurricane speeds exceeding 2,000 miles per hour. On the dark side, the silicon monoxide may cool enough to condense into rock that rains out of clouds, but even at dawn and dusk, the planet is hot enough to vaporize rock. "We knew we had seen something really interesting with this silicon monoxide feature," said Josh Lothringer of the Utah Valley University in Orem, Utah
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weatheriscool
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Re: Exoplanets – worlds of other suns

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caltrek wrote: Wed Apr 06, 2022 3:44 pm Hubble Probes Extreme Weather on Ultra-hot Jupiters
April 6, 2022

https://www.eurekalert.org/news-releases/948943

Introduction:
(EurekAlert) In studying a unique class of ultra-hot exoplanets, NASA Hubble Space Telescope astronomers may be in the mood for dancing to the Calypso party song "Hot, Hot, Hot." That's because these bloated Jupiter-sized worlds are so precariously close to their parent star they are being roasted at seething temperatures above 3,000 degrees Fahrenheit. That's hot enough to vaporize most metals, including titanium. They have the hottest planetary atmospheres ever seen.

In two new papers, teams of Hubble astronomers are reporting on bizarre weather conditions on these sizzling worlds. It's raining vaporized rock on one planet, and another one has its upper atmosphere getting hotter rather than cooler because it is being "sunburned" by intense ultraviolet (UV) radiation from its star.

This research goes beyond simply finding weird and quirky planet atmospheres. Studying extreme weather gives astronomers better insights into the diversity, complexity, and exotic chemistry taking place in far-flung worlds across our galaxy.

"We still don't have a good understanding of weather in different planetary environments," said David Sing of the Johns Hopkins University in Baltimore, Maryland, co-author on two studies being reported. "When you look at Earth, all our weather predictions are still finely tuned to what we can measure. But when you go to a distant exoplanet, you have limited predictive powers because you haven't built a general theory about how everything in an atmosphere goes together and responds to extreme conditions. Even though you know the basic chemistry and physics, you don't know how it's going to manifest in complex ways."

In a paper in the April 7 journal Nature, astronomers describe Hubble observations of WASP-178b, located about 1,300 light-years away. On the daytime side the atmosphere is cloudless, and is enriched in silicon monoxide gas. Because one side of the planet permanently faces its star, the torrid atmosphere whips around to the nighttime side at super-hurricane speeds exceeding 2,000 miles per hour. On the dark side, the silicon monoxide may cool enough to condense into rock that rains out of clouds, but even at dawn and dusk, the planet is hot enough to vaporize rock. "We knew we had seen something really interesting with this silicon monoxide feature," said Josh Lothringer of the Utah Valley University in Orem, Utah
It's insane how the typical solar system is being found with so many of these close in jupiters that are extremely hot. One theory for this is they developed further out and moved in destroying all the rocky planets as they did so...This kind of sucks for the possibility for life outside of our solar system. Anyways, the winds on such a hot jupiter must be many thousands of miles per hour and it would be fun to image one day. ;)
weatheriscool
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Re: Exoplanets – worlds of other suns

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Two new Saturn-mass exoplanets discovered

by Tomasz Nowakowski, Science X Network, Phys.org
https://phys.org/news/2022-04-saturn-ma ... anets.html
An international team of astronomers reports the detection of two new Saturn-mass exoplanets as part of the CARMENES radial velocity survey. The newly found alien worlds, designated TYC 2187-512-1 b and TZ Ari b, orbit nearby M-dwarf stars. The finding was presented in a paper published March 30 on arXiv.org.

Thanks to the radial velocity (RV) technique, more than 600 exoplanets have been detected so far and more than 100 of them have been found around M dwarfs. The Calar Alto high-Resolution search for M dwarfs with Exoearths with Near-infrared and optical Echelle Spectrographs (CARMENES) project has been crucial in the search for new alien worlds orbiting these most common stars in our galaxy.

Recently, a group of researchers led by Andreas Quirrenbach of Heidelberg University in Germany has announced the discovery of another two extrasolar worlds as part of the CARMENES survey. The observations conducted with the 3.5 m telescope at the Calar Alto observatory in Almería, Spain, have confirmed that two nearby M dwarfs, TYC 2187-512-1 and TZ Ari, host massive planets.
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Re: Exoplanets – worlds of other suns

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A quarter century of spectroscopic monitoring of the nearby M dwarf Gl 514. A super-Earth on an eccentric orbit moving in and out of the habitable zone
https://arxiv.org/abs/2204.06376

Quote :
We investigated the presence of planetary companions around the nearby (7.6 pc) and bright (V=9 mag) early-type M dwarf Gl 514, analysing 540 radial velocities collected over nearly 25 years with the HIRES, HARPS, and CARMENES spectrographs. The data are affected by time-correlated signals at the level of 2-3 ms−1 due to stellar activity, that we filtered out testing three different models based on Gaussian process regression. As a sanity cross-check, we repeated the analyses using HARPS radial velocities extracted with three different algorithms. We used HIRES radial velocities and Hipparcos-Gaia astrometry to put constraints on the presence of long-period companions, and we analysed TESS photometric data. We found strong evidence that Gl 514 hosts a super-Earth on a likely eccentric orbit, residing in the conservative habitable zone for nearly 34% of its orbital period. The planet Gl 514 b has minimum mass mbsinib=5.2±0.9 MEarth, orbital period Pb=140.43±0.41 days, and eccentricity eb=0.45+0.15−0.14. No evidence for transits is found in the TESS light curve. There is no evidence for a longer period companion in the radial velocities and, based on astrometry, we can rule out a ∼0.2 MJup planet at a distance of ∼3−10 au, and massive giant planets/brown dwarfs out to several tens of au. We discuss the possible presence of a second low-mass companion at a shorter distance from the host than Gl 514 b. Gl 514 b represents an interesting science case to study the habitability of planets on eccentric orbits. We advocate for additional spectroscopic follow-up to get more accurate and precise planetary parameters. Further follow-up is also needed to investigate sub \ms and shorter period signals.

Tuomi (2019) also claimed the presence of a planet at this star.
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Re: Exoplanets – worlds of other suns

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Team behind discovery of planet with three stars retracts their article
https://phys.org/news/2022-04-team-disc ... racts.html
by Bob Yirka , Phys.org
An international team of researchers who published a paper in the journal Science in 2016 describing their discovery of an exoplanet with three stars, has now retracted that paper.

In their original paper, the team described their work with direct imaging technology to study the triple-star system HD 131399. They spotted what they believed to be an exoplanet approximately four times the size of Jupiter. They also noted its apparent odd orbital system—the planet appeared to orbit just one of the stars while the other two stars were farther away.

Subsequent to the publishing of the paper, in 2017, another international team of researchers found evidence suggesting that the planet was not a planet after all—the data observed the year before, they claimed, was from a background object, perhaps a dwarf star. They further noted in their paper published in The Astronomical Journal, that the object was much more likely to be something moving unusually fast in the background in a path that coincided with star system HD 131399.
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Re: Exoplanets – worlds of other suns

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Second alien world detected in the planetary system HD 83443

by Tomasz Nowakowski , Phys.org
https://phys.org/news/2022-04-alien-wor ... ry-hd.html
Astronomers report the discovery of another exoplanet around a nearby star known as HD 83443. The newfound extrasolar world is a Jupiter-mass planet orbiting its host on a highly eccentric 22-year orbit. The finding was detailed in a paper published April 12 on the arXiv pre-print server.

Located some 133 light years away, HD 83443 is a solar mass K0 star, with more than twice the metallicity of the sun. The age of this star is estimated to be 2.64 billion years and its effective temperature is around 5,429 K. HD 83443 is known to host a "hot Jupiter" exoplanet (designated HD 83443 b), with a mass of some 0.41 Jupiter masses, which orbits it approximately every three days.

Now, a team of astronomers led by Adriana Errico of the University of Southern Queensland in Australia, reports the detection of another giant planet orbiting HD 83443, which was suggested by previous studies. The finding is a result of analyzing radial velocity data from four instruments, namely: the University College London Echelle Spectrograph (UCLES) at the 3.9 m Anglo-Australian Telescope (AAT), the High Resolution Echelle Spectrometer (HIRES) at the Keck Telescope, the High Accuracy Radial velocity Planet Searcher (HARPS) at the ESO La Silla 3.6m telescope, and also the MINERVA-Australis telescope array at the Mount Kent Observatory.

"HD 83443 has been observed by four precise radial velocity instruments spanning a baseline of over 22 years. Here we give details about the observations from each instrument," the researchers wrote in the paper.
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Re: Exoplanets – worlds of other suns

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The HD 260655 system: Two rocky worlds transiting a bright M dwarf at 10 pc
https://arxiv.org/abs/2204.10261
Quote :
We report the discovery of a multi-planetary system transiting the M0 V dwarf HD 260655 (GJ 239, TOI-4599). The system consists of at least two transiting planets, namely HD 260655 b, with a period of 2.77 d, a radius of Rb = 1.240±0.023 R⊕, a mass of Mb = 2.14±0.34 M⊕, and a bulk density of ρb = 6.2±1.0 g cm−3, and HD 260655 c, with a period of 5.71 d, a radius of Rc = 1.533+0.051−0.046 R⊕, a mass of Mc = 3.09±0.48 M⊕, and a bulk density of ρc = 4.7+0.9−0.8 g cm−3. The planets were detected in transit by the TESS mission and confirmed independently with archival and new precise radial velocities obtained with the HIRES and CARMENES instruments since 1998 and 2016, respectively. At a distance of 10 pc, HD 260655 becomes the fourth closest known multi-transiting planet system after HD 219134, LTT 1445 A, and AU Mic. Due to the apparent brightness of the host star (J = 6.7 mag), both planets are among the most suitable rocky worlds known today for atmospheric studies with the JWST, both in transmission and emission.
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Re: Exoplanets – worlds of other suns

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A low-eccentricity migration pathway for a 13-h-period Earth analogue in a four-planet system
https://arxiv.org/abs/2204.13573
It is commonly accepted that exoplanets with orbital periods shorter than 1 day, also known as ultra-short period (USP) planets, formed further out within their natal protoplanetary disk, before migrating to their current-day orbits via dynamical interactions. One of the most accepted theories suggests a violent scenario involving high-eccentricity migration followed by tidal circularization. Here, we present the discovery of a four planet system orbiting the bright (V=10.5) K6 dwarf star TOI-500. The innermost planet is a transiting, Earth-sized USP planet with an orbital period of ∼ 13 hours, a mass of 1.42 ± 0.18 M⊕, a radius of 1.166+0.061−0.058 R⊕, and a mean density of 4.89+1.03−0.88 gcm−3. Via Doppler spectroscopy, we discovered that the system hosts three outer planets on nearly circular orbits with periods of 6.6, 26.2, and 61.3d and minimum masses of 5.03 ± 0.41 M⊕, 33.12 ± 0.88 M⊕ and 15.05+1.12−1.11 M⊕, respectively. The presence of both a USP planet and a low-mass object on a 6.6-day orbit indicates that the architecture of this system can be explained via a scenario in which the planets started on low-eccentricity orbits, then moved inwards through a quasi-static secular migration. Our numerical simulations show that this migration channel can bring TOI-500 b to its current location in 2 Gyrs, starting from an initial orbit of 0.02au. TOI-500 is the first four planet system known to host a USP Earth analog whose current architecture can be explained via a non-violent migration scenario.
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Re: Exoplanets – worlds of other suns

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Two rocky exoplanets discovered around nearby star
https://phys.org/news/2022-04-rocky-exo ... -star.html
by Tomasz Nowakowski , Phys.org

Using NASA's Transiting Exoplanet Survey Satellite (TESS), astronomers have detected two rocky alien worlds orbiting a nearby M dwarf star known as HD 260655. The newly found exoplanets are larger and at least two times more massive than the Earth. The finding is reported in a paper published April 21 on arXiv.org.

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 5,600 candidate exoplanets (TESS Objects of Interest, or TOI), of which 205 have been confirmed so far.

Now, a team of astronomers led by Rafael Luque of the University of Chicago confirmed another two planets monitored by TESS. They report that transit signals have been identified in the light curve of the bright M dwarf HD 260655 (or TOI-4599). The planetary nature of these signals was confirmed by archival and new precise radial velocity (RV) measurements.

"This work presents the discovery and characterization of a multiplanetary system orbiting the nearby M dwarf HD 260655. Transit observations from TESS detected two small planet candidates that were confirmed with independent RV data from the HIRES and CARMENES instruments taken since 1998 and 2016, respectively," the researchers wrote in the paper.
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