Exoplanets – worlds of other suns

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wjfox
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Re: Exoplanets – worlds of other suns

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firestar464
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Re: Exoplanets – worlds of other suns

Post by firestar464 »

I could write a sci-fi about this about an alien civilization there and it would make sense to have such a civilization base their festivals and their religion(s) on the long orbit of their planet.

Just a random thought.
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Re: Exoplanets – worlds of other suns

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Cold Jupiters and improved masses in 38 Kepler and K2 small-planet systems from 3661 high-precision HARPS-N radial velocities. No excess of cold Jupiters in small-planet systems
https://arxiv.org/abs/2304.05773

Quote :
The exoplanet population with orbital periods P<100 d around solar-type stars is dominated by super-Earths and sub-Neptunes. These planets are, however, missing in our Solar System, and the reason for that is unknown. Two theoretical scenarios invoke the role of Jupiter as the possible culprit: Jupiter may have acted as a dynamical barrier to the inward migration of sub-Neptunes from beyond the water iceline or, alternatively, may have reduced considerably the inward flux of material (pebbles) required to form super-Earths inside that iceline. Both scenarios predict an anti-correlation between the presence of small planets (SPs) and that of cold Jupiters (CJs) in exoplanetary systems. To test that prediction, we homogeneously analyzed the radial-velocity (RV) measurements of 38 Kepler and K2 transiting SP systems gathered over almost 10 years with the HARPS-N spectrograph, as well as publicly available RVs collected with other facilities. We detected five CJs in three systems, two in Kepler-68, two in Kepler-454, and a very eccentric one in K2-312. We derived an occurrence rate of 9.3+7.7−2.9% for CJs with 0.3−13 MJup and 1-10 au, which is lower but still compatible at 1.3σ with that measured from RV surveys for solar-type stars, regardless of SP presence. This does not allow us to draw a firm conclusion about the predicted anti-correlation between SPs and CJs, which would require a considerably larger sample. Nevertheless, we found no evidence of previous claims of an excess of CJs in SP systems. As an important by-product of our analyses, we homogeneously determined the masses of 64 Kepler and K2 small planets, reaching a precision better than 5, 7.5 and 10σ for 25, 13 and 8 planets, respectively. Finally, we release to the scientific community the 3661 HARPS-N radial velocities used in this work.
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Re: Exoplanets – worlds of other suns

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In a research first, team uses precision astrometry to discover new exoplanet outside Earth's solar system

by University of Texas at San Antonio
https://phys.org/news/2023-04-team-prec ... earth.html
An international research team led by UTSA Associate Professor of Astrophysics Thayne Currie has made a breakthrough in accelerating the search for new planets.

In a paper published in Science, Currie reports the first exoplanet jointly discovered through direct imaging and precision astrometry, a new indirect method that identifies a planet by measuring the position of the star it orbits. Data from the Subaru Telescope in Hawai'i and space telescopes from the European Space Agency (ESA) were integral to the team's discovery.

An exoplanet—also called an extrasolar planet—is a planet outside a solar system that orbits another star. With direct imaging, astronomers can see an exoplanet's light in a telescope and study its atmosphere. However, only about 20 have been directly imaged over the past 15 years.

By contrast, indirect planet detection methods determine a planet's existence through its effect on the star it orbits. This approach can provide detailed measurements of the planet's mass and orbit.

Combining direct and indirect methods to examine a planet's position provides a more complete understanding of an exoplanet, Currie says.
Jakob
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Re: Exoplanets – worlds of other suns

Post by Jakob »

wjfox wrote: Thu Apr 06, 2023 11:22 am








The problem with these sorts of systems is that stars like Rigel have lifespans in the millions of years, not billions, which probably isn't enough time for any life to form at all, let alone complex life. Of course that doesn't really matter as far as human colonization goes, but any colony there would eventually have to deal with their star going supernova. That's something that could happen on planets orbiting smaller stars too, but a billion years from now there won't be anything recognizably human to witness the stars exploding, whereas we can't really say the same about a mere million years from now.
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Re: Exoplanets – worlds of other suns

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TESS discovers a Venus-sized exoplanet orbiting nearby star
https://phys.org/news/2023-04-tess-venu ... earby.html
by Tomasz Nowakowski , Phys.org
Image

Using NASA's Transiting Exoplanet Survey Satellite (TESS), a team of astronomers from Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Massachusetts, and elsewhere has detected a new exoplanet. The newfound alien world, designated LHS 475 b, is about the size of Venus and orbits a nearby M-dwarf star. The discovery was reported April 4 on the arXiv pre-print repository.

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 nearly 6,400 candidate exoplanets (TESS Objects of Interest, or TOI), of which 3,031 have been confirmed so far.

Now, a group of astronomers led by CfA's Kristo Ment reports the discovery of another extrasolar planet with TESS. They reveal that a transit signal was detected in the light curve of LHS 475—a main-sequence red dwarf belonging to the M3 spectral class. The planetary nature of this signal was confirmed by follow-up ground-based photometry using the MEarth-South telescope array at the Cerro Tololo Inter-American Observatory in Chile.

"Here we present the discovery and subsequent ground-based validation observations of LHS 475 b, a Venus-sized planet orbiting a nearby M dwarf," the researchers wrote in the paper.

LHS 475 b has a radius of approximately 0.955 Earth radii and orbits its host every 48.7 hours, at a distance of about 0.02 AU from it. The planet's equilibrium temperature was estimated to be some 587 K, thus LHS 475 b is likely too hot to be habitable.
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Re: Exoplanets – worlds of other suns

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Earth-like exoplanets may be much more common than previously thought
By David Szondy
April 16, 2023

A new study led by UCLA scientists on how water forms on young exoplanets with hydrogen atmospheres and molten oceans of magma suggests that Earth-like planets may not be as uncommon as once thought and that the presence of water on such planets may be almost inevitable.

One of the historically annoying things about trying to figure out how many planets like Earth that there are in the galaxy is that we only have one real example of an Earth-like planet and we're standing on it.

Since a total sample size of exactly one is statistically meaningless, scientists are very keen to find Earth-like planets outside the Solar System or, at least, ones that can give us insights into the mechanisms that form such planets so meaningful conclusions can be drawn.

One key property that sets Earth apart is the presence of large amounts of liquid water on its surface – a necessary factor for the existence of life. Current hypotheses about how Earth got its water revolve mainly around it being carried to the primordial planet by comets, meteors, or space dust. This is a mechanism that requires very specific circumstances and suggests that watery Earth-like planets may be exceedingly rare.
https://newatlas.com/space/earthlike-ex ... re-common/
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Re: Exoplanets – worlds of other suns

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New exoplanet seen via direct imaging

19th April 2023

The discovery of HIP 99770 b, a new exoplanet located 133 light years away, is reported in the journal Science. A team of astronomers used a new detection method that combines direct imaging with astrometry.

As of today, there are 5,363 confirmed exoplanets in 3,960 planetary systems. However, only a handful have been seen via direct imaging. Exoplanets are extremely faint compared with their parent stars, making it difficult to spot them in visible light.

A gas giant called HIP 99770 b is the latest of these very few exoplanets confirmed via direct imaging. It has also become the first jointly discovered from both direct imaging and precision astrometry, a new indirect method that identifies a planet by measuring the position of the star it orbits.

Combining these direct and indirect methods can provide a more complete understanding of an exoplanet's characteristics, according to the authors of a study that appears this month in the journal Science.

"Indirect planet detection methods are responsible for most exoplanet discoveries thus far. Using one of these methods – precision astrometry – told us where to look to try to image planets. And, as we found out, we can now see planets a lot easier," said Thayne Currie, Associate Professor of Astrophysics at the University of Texas at San Antonio.

Read more: https://www.futuretimeline.net/blog/202 ... planet.htm


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weatheriscool
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Re: Exoplanets – worlds of other suns

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Two super-Earths at the edge of the habitable zone of the nearby M dwarf TOI-2095
https://arxiv.org/abs/2304.09220
The planetary system is composed of two transiting planets: TOI-2095b with an orbital period of Pb=17.66484±(7×10−5) days and TOI-2095c with Pc=28.17232±(14×10−5) days. Both planets have similar sizes with Rb=1.25±0.07R⊕ and Rc=1.33±0.08R⊕ for planet b and c, respectively. We put upper limits on the masses of these objects with Mb<4.1M⊕ for the inner and Mc<7.4M⊕ for the outer planet (95\% confidence level). These two planets present equilibrium temperatures in the range of 300 - 350 K and are close to the inner edge of the habitable zone of their star.
Two Warm Super-Earths Transiting the Nearby M Dwarf TOI-2095
https://arxiv.org/abs/2304.09189
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Re: Exoplanets – worlds of other suns

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Researchers use AI to discover new planet outside solar system
https://phys.org/news/2023-04-ai-planet-solar.html
by Alan Flurry, University of Georgia

A University of Georgia research team has confirmed evidence of a previously unknown planet outside of our solar system, and they used machine learning tools to detect it.

A recent study by the team showed that machine learning can correctly determine if an exoplanet is present by looking in protoplanetary disks, the gas around newly formed stars.

The newly published findings in The Astrophysical Journal represent a first step toward using machine learning to identify previously overlooked exoplanets.

"We confirmed the planet using traditional techniques, but our models directed us to run those simulations and showed us exactly where the planet might be," 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.

"When we applied our models to a set of older observations, they identified a disk that wasn't known to have a planet despite having already been analyzed. Like previous discoveries, we ran simulations of the disk and found that a planet could re-create the observation."

According to Terry, the models suggested a planet's presence, indicated by several images that strongly highlighted a particular region of the disk that turned out to have the characteristic sign of a planet—an unusual deviation in the velocity of the gas near the planet.

"This is an incredibly exciting proof of concept. We knew from our previous work that we could use machine learning to find known forming exoplanets," said Cassandra Hall, assistant professor of computational astrophysics and principal investigator of the Exoplanet and Planet Formation Research Group at UGA. "Now, we know for sure that we can use it to make brand new discoveries."
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