Exoplanets – worlds of other suns

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weatheriscool
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Re: Exoplanets – worlds of other suns

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Astronomers detect signature of magnetic field on an exoplanet
https://phys.org/news/2021-12-astronome ... lanet.html
by University of Arizona
Researchers have identified the first signature of a magnetic field surrounding a planet outside of our solar system. Earth's magnetic field acts as a shield against energetic particles from the sun known as the solar wind. Magnetic fields could play similar roles on other planets.

An international team of astronomers used data from the Hubble Space Telescope to discover the signature of a magnetic field in a planet outside our solar system. The finding, described in a paper in the journal Nature Astronomy, marks the first time such a feature has been seen on an exoplanet.

A magnetic field best explains the observations of an extended region of charged carbon particles that surround the planet and stream away from it in a long tail. Magnetic fields play a crucial role in protecting planetary atmospheres, so the ability to detect the magnetic fields of exoplanets is a significant step toward better understanding what these alien worlds may look like.

The team used Hubble to observe the exoplanet HAT-P-11b, a Neptune-sized planet 123 light-years from Earth, pass directly across the face of its host star six times in what is known as a "transit." The observations were made in the ultraviolet light spectrum, which is just beyond what the human eye can see.
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Re: Exoplanets – worlds of other suns

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Astronomers uncover largest group of rogue planets yet
https://phys.org/news/2021-12-eso-teles ... group.html
by ESO
Rogue planets are elusive cosmic objects that have masses comparable to those of the planets in our Solar System but do not orbit a star, instead roaming freely on their own. Not many were known until now, but a team of astronomers, using data from several European Southern Observatory (ESO) telescopes and other facilities, have just discovered at least 70 new rogue planets in our galaxy. This is the largest group of rogue planets ever discovered, an important step towards understanding the origins and features of these mysterious galactic nomads.

"We did not know how many to expect and are excited to have found so many," says Núria Miret-Roig, an astronomer at the Laboratoire d'Astrophysique de Bordeaux, France and the University of Vienna, Austria, and the first author of the new study published today in Nature Astronomy.

Rogue planets, lurking far away from any star illuminating them, would normally be impossible to image. However, Miret-Roig and her team took advantage of the fact that, in the few million years after their formation, these planets are still hot enough to glow, making them directly detectable by sensitive cameras on large telescopes. They found at least 70 new rogue planets with masses comparable to Jupiter's in a star-forming region close to our Sun, in the Upper Scorpius and Ophiuchus constellations.
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Re: Exoplanets – worlds of other suns

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TOI 560 : Two Transiting Planets Orbiting a K Dwarf Validated with iSHELL, PFS and HIRES RVs
https://arxiv.org/abs/2112.13448
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Re: Exoplanets – worlds of other suns

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Astronomers Detect an Exoplanet’s Magnetic Field for the First Time
https://www.extremetech.com/extreme/329 ... first-time
By Ryan Whitwam on December 27, 2021 at 10:04 am

All we can say about most of the 4,000+ known exoplanets is that they exist. Their physical characteristics are unknowable with current technology, but a few have given up some secrets. Astronomers using the Hubble Space Telescope have identified a magnetic field around the exoplanet HAT-P-11b. Earth’s magnetic field is essential for our continued existence, and this is the first time we’ve confirmed one around an exoplanet.

Earth and several other objects in our solar system have magnetic fields, a consequence of the way planets and moons interact with the solar wind. On Earth, the magnetosphere deflects damaging radiation, which would otherwise render the surface inhospitable. Fields surrounding exoplanets could serve a similar purpose. There was every reason to think exoplanets could have magnetic fields like the ones we see locally, but this is the first time we’ve been able to confirm that.

Astronomers from the University of Arizona observed the exoplanet HAT-P-11 b across six transits — that’s when the exoplanet passes in front of its host star from our perspective. This is how the HATNet Project discovered HAT-P-11 b in 2009. It was confirmed and further characterized later using radial velocity measurements from the Keck Observatory, which is the other standard method for detecting distant planets. Although, HAT-P-11 b is relatively close in the grand scheme at just 123 light years away.
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Re: Exoplanets – worlds of other suns

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A 38 Million Year Old Neptune-Sized Planet in the Kepler Field
https://arxiv.org/abs/2112.14776
Kepler 1627A is a G8V star previously known to host a 3.8 Earth-radius planet on a 7.2 day orbit. The star was observed by the Kepler space telescope because it is nearby (d=329 pc) and it resembles the Sun. Here we show using Gaia kinematics, TESS stellar rotation periods, and spectroscopic lithium abundances that Kepler 1627 is a member of the 38 ± 6 Myr old δ Lyr cluster. To our knowledge, this makes Kepler 1627Ab the youngest planet with a precise age yet found by the prime Kepler mission. The Kepler photometry shows two peculiarities: the average transit profile is asymmetric, and the individual transit times might be correlated with the local light curve slope. We discuss possible explanations for each anomaly. More importantly, the δ Lyr cluster is one of about 103 coeval groups whose properties have been clarified by Gaia. Many other exoplanet hosts are candidate members of these clusters; these memberships can be verified with the trifecta of Gaia, TESS, and ground-based spectroscopy.
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Re: Exoplanets – worlds of other suns

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Eccentric exoplanet discovered
https://phys.org/news/2022-01-eccentric-exoplanet.html
by University of Bern
Led by the University of Bern, an international research team has discovered a sub-Neptune exoplanet orbiting a red dwarf star. The discovery was also made thanks to observations performed by the SAINT-EX observatory in Mexico. SAINT-EX is run by a consortium including the Center for Space and Habitability (CSH) at the University of Bern and the National Center of Competence in Research NCCR PlanetS.

"Red dwarfs" are small stars and thus much cooler than our Sun. Around stars like these, liquid water is possible on planets much closer to the star than in our solar system. The distance between an exoplanet and its star is a crucial factor in its detection: the closer a planet is to its host star, the higher the probability that it can be detected.

In a study recently published in the journal Astronomy & Astrophysics, researchers led by Dr. Nicole Schanche of the Center for Space and Habitability CSH of the University of Bern report the discovery of the exoplanet TOI-2257 b orbiting a nearby red dwarf. Nicole Schanche is also a member of the National Center of Competence in Research PlanetS, which the University of Bern runs together with the University of Geneva.
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New sub-Jupiter-mass exoplanet detected by astronomers
https://phys.org/news/2022-01-sub-jupit ... omers.html
by Tomasz Nowakowski , Phys.org

An international team of astronomers reports the detection of a new sub-Jupiter-mass alien world orbiting an M-dwarf star. The newly found exoplanet, designated OGLE-2014-BLG-0319Lb, turns out to be about half as massive as Jupiter. The discovery was detailed in a paper published December 30 on the arXiv pre-print repository.

Based on the gravitational lens effect, the microlensing method is mainly used to detect planetary and stellar-mass objects regardless of the light they emit. This technique is therefore sensitive to the mass of the objects, rather than their luminosity, which allows astronomers to study objects that emit little or no light at all.

The discovery of the microlensing event OGLE-2014-BLG-0319 was announced on March 21, 2014 by the Optical Gravitational Lensing Experiment (OGLE) collaboration. The event was also detected by the Microlensing Observations in Astrophysics (MOA) team and received designation MOA-2014-BLG-171.

Recently, a group of astronomers led by Shota Miyazaki of Osaka University in Japan has analyzed this microlensing event, what revealed the signal indicating the presence of a planetary object. Generally, planetary signals in microlensing events manifest as short-lived anomalous deviations from typical single-lens light curves. Sometimes, these deviations produce a degeneracy problem where several model interpretations are possible for an anomaly.
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Re: Exoplanets – worlds of other suns

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Cheops reveals a rugby-ball-shaped exoplanet

by European Space Agency
https://phys.org/news/2022-01-cheops-re ... lanet.html
ESA's exoplanet mission Cheops has revealed that an exoplanet orbiting its host star within a day has a deformed shape more like that of a rugby ball than a sphere. This is the first time that the deformation of an exoplanet has been detected, offering new insights into the internal structure of these star-hugging planets.

The planet, known as WASP-103b is located in the constellation of Hercules. It has been deformed by the strong tidal forces between the planet and its host star WASP-103, which is about 200 degrees hotter and 1.7 times larger than the sun.

Tidal tug

We experience tides in the oceans of Earth mainly due to the Moon tugging slightly on our planet as it orbits us. The sun also has a small but significant effect on tides, however it is too far from Earth to cause major deformations of our planet. The same cannot be said for WASP-103b, a planet almost twice the size of Jupiter with 1.5 times its mass, orbiting its host star in less than a day. Astronomers have suspected that such a close proximity would cause monumental tides, but up until now they haven't been able to measure them.

Using new data from ESA's Cheops space telescope, combined with data that had already been obtained by the NASA/ESA Hubble Space Telescope and NASA's Spitzer Space Telescope, astronomers have now been able to detect how tidal forces deform exoplanet WASP-103b from a usual sphere into a rugby ball shape.
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A pair of Sub-Neptunes transiting the bright K-dwarf TOI-1064 characterised with CHEOPS
https://arxiv.org/abs/2201.03570
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Newly-discovered planets will be 'swallowed' by their stars
https://phys.org/news/2022-01-newly-dis ... stars.html
by University of Hawaii at Manoa
Astronomers at the University of Hawaiʻi Institute for Astronomy (IfA) are part of a team that recently discovered three planets orbiting dangerously close to stars nearing the ends of their lives.

Out of the thousands of extrasolar planets found so far, these three gas giant planets, first detected by the NASA TESS (Transiting Exoplanet Survey Satellite) Mission, have some of the shortest-period orbits around subgiant or giant stars. One of the planets, TOI-2337b, will be consumed by its host star in less than 1 million years, sooner than any other planet currently known.

"These discoveries are crucial to understanding a new frontier in exoplanet studies: how planetary systems evolve over time," explained lead author Samuel Grunblatt, a postdoctoral fellow at the American Museum of Natural History and the Flatiron Institute in New York City. Grunblatt, who earned his Ph.D. from the IfA, added that "these observations offer new windows into planets nearing the end of their lives, before their host stars swallow them up."

The discovery and confirmation of the planets has been accepted for publication in the Astronomical Journal, and was announced on January 13 at an American Astronomical Society press conference. The researchers estimate that the planets have masses between 0.5–1.7 times Jupiter's mass, and sizes that range from slightly smaller to more than 1.6 times the size of Jupiter. They also span a wide range of densities, from the density of cork to three times denser than water, implying a wide variety of origins.

These three planets are believed to be just the tip of the iceberg. "We expect to find tens to hundreds of these evolved transiting planet systems with TESS, providing new details on how planets interact with each other, inflate, and migrate around stars, including those like our Sun," said Nick Saunders, a graduate student at IfA and co-author of the study.
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