Nature versus nurture refers to a long-standing debate between scientists who are trying to figure out whether human behavior is determined by the environment or is simply the result of a person’s genes. Planets and people can have a lot in common, and the atmospheres of a duo of Hot jupiter exoplanets is a good example. These two worlds serve as examples of how nature versus nurture it operates when it comes to these two “prime” exoplanets. In a unique experiment, planet-hunting astronomers used the Hubble Space Telescope (HST) to observe the Hot jupiter “cousins,” and because these two distant, fiery, gaseous worlds are virtually identical in both size and temperature, and surround their nearly identical parent stars at the same distance, astronomers thought their atmospheres would also be similar. What they found surprised them: one of these kindred worlds is more cloudy than the other, and the difference between these distant worlds is now a delightful mystery waiting to be solved by curious planetary scientists who are trying to understand why this difference exists between two. of those worlds. closely related worlds.
The lead scientists, Dr. Giovanni Bruno of the Space Telescope Science Institute (STSI) in Baltimore, Maryland, explained on a June 5, 2017 STSI press release that “What we are seeing when looking at the two atmospheres is that they are not the same. One planet – WASP-67b is more cloudy than the other – HAT-P-38b. We do not see what we are expecting, and we must understand why we find this difference “.
Planetary scientists used HST Wide Field Camera 3 to look at the spectral fingerprints of the two “prime” exoplanets, which measure chemical composition. “The effect that clouds have on the spectral signature of the water allows us to measure the amount of clouds in the atmosphere. More clouds means that the characteristic of the water is reduced,” added Dr. Bruno.
“This tells us that there had to be something in their past that is changing the appearance of these planets,” he continued to explain.
From a historical perspective, the search for distant alien worlds, located within the star families beyond our own Sun, turned out to be a difficult task. The discovery of the first exoplanets a generation ago clearly represents one of humanity’s greatest achievements. Detecting a giant planet, such as Jupiter, the banded giant of our own Solar System, has been compared to observing the leaping light of a mosquito flying in front of a 1000-watt lamp on a street lamp, when the observer is 10 miles away. distance. .
Discovery
The lower the exoplanet, the more difficult it is to discover. For example, if an alien astronomer from a technologically advanced civilization were to hunt for other planets in remote regions of our Milky Way, he would have a hard time finding our little planet. This is because our Earth would appear to be only a faint and insignificant blob in the vastness of space. In fact, our planet is very well hidden from curious alien astronomers because the glare from our star overwhelms it.
The first detection of an exoplanet occurred in 1988. However, the first confirmed discovery came in 1992, with the detection of some strange and hostile planets surrounding a dense stellar corpse the size of a city called press. Pulsars they are the lingering relics of massive stars that have perished in the terrible fury of a supernova explosion. This raging, fatal and final blaze of glory marks the violent and catastrophic end of the star that was.
Astronomers detected the first exoplanet orbiting a still “living” star, like our own Sun, in 1995. However, this landmark discovery left a trail of confusion. The newly discovered alien world, nicknamed 51 Pegasi b, it was unlike anything planetary scientists thought could exist. 51 pin b it’s a Hot jupiter– a giant gaseous world, like the Jupiter of our Solar System, that tightly embraces its parent star in a toasting orbit that is much closer to its stellar parent than Mercury’s orbit around our Sun. Before the discovery of 51 pin b, most astronomers thought that the gas giant planets could only exist much further away from their stars, comparable to the distance from Jupiter to our Sun. Jupiter is in the cold outer region of our Solar System.
The original technique used by astronomers in 1995: the Doppler shift method: favors the discovery of giant planets that revolve around their parent stars in close, fiery orbits. Tea Doppler shift The method looks for a small wobble induced in a star by an orbiting planet: the larger the planet, the larger the wobble and the easier it is for planet-hunting astronomers to detect.
As of June 1, 2017, 3,610 exoplanets have been discovered, inhabiting 2,704 planetary systems, and 610 multiple planetary systems have also been verified. Since 2004, European Southern Observatory (ESO) High Precision Radial Velocity Planet Finder (HARPS) 3.6-meter telescope has detected approximately 100 exoplanets, and since 2009, NASA Kepler space telescope has discovered more than two thousand. Kepler it has also detected a few thousand candidate planets, of which only about 11% can be false positives. Planet hunter astronomers estimate that about 1 in 5 stars similar to our Sun is orbited by an “Earth-sized” planet located in the living room circling his star. Tea living room of a star is that Goldilocks region where temperatures are not too hot, not too cold, but just right for water to exist in its life-sustaining liquid phase. Where liquid water exists, life can also potentially evolve. If there are 200 billion stars inhabiting our galaxy, it could be that there are 11 billion potentially habitable worlds the size of Earth in our Milky Way. This number, which is already huge, could increase even more if the planets surrounding the numerous and long-lived red dwarf stars are included in the estimate. red dwarf stars are the smallest, coldest, and most abundant true stars that inhabit our galaxy. Red dwarfs they are even smaller than our own little Sun, and can potentially remain on burning hydrogen Main sequence of the Hertzsprung-Russell diagram of stellar evolution by trillion of years. For this reason, it is generally thought that there is no red dwarf relics that inhabit the Cosmos. This is because our Universe is “mere” 13.8 billion years old, and not red dwarf has had enough time to die since the Big Bang.
The least massive exoplanet discovered so far is Draugr (PSR B1257 + 12A gold PSR B1257 + 12B), which weighs only twice the mass of our planet’s Moon. In contrast, the most massive exoplanet known is DENIS-P J082303.11-491201 b, and it is about 29 times more massive than Jupiter. However, according to some definitions of planet, this extremely large world is too massive to be a planet, and it may be a kind of failed star called brown dwarf. Brown dwarfs are relatively small distant worlds that probably form in the same way as their true stellar relatives, but never manage to reach the mass necessary to illuminate their nuclear fusion fires. These star rifts are actually a pretty purple-pink color called magenta, and are born as a result of the collapse of a dense pocket embedded within the swirling and undulating folds of a cold and giant molecular cloud– just like its more successful stellar relative.
Some exoplanets cling tightly to their parent star in such tight and fiery orbits that it only takes a few hours to complete a single orbit. However, there are other alien planets that take thousands of years to circle your star. In fact, some exoplanets are so far from their parent star that it is sometimes very difficult for astronomers to determine whether they are actually gravitationally bound to it. Almost all the exoplanets discovered so far are inhabitants of our own galaxy, the Milky Way, but there have also been detections of a handful of intriguing extragalactic exoplanets, but not yet confirmed. The closest exoplanet to Earth is called Proxima Centauri bwhat circles Proxima Centauri, the closest star to our own Sun. Proxima Centauri b it is “only” 4.2 light years from Earth.
There is also a large population of the so-called rogue planets, who do not belong to the family of any stars at all, but rather roam the desert of interstellar space without a parent star to call upon. Unfortunately, these lonely and lonely alien worlds were likely once members of a planetary system, but were rudely dislodged by gravitational pulls from sister worlds, or by gravitational disruption caused when a traveling star passed too close to its own stellar parent. . Astronomers tend to consider these lonely worlds separately, especially if they are gas giant planets. If this is the case, these rogue planets are frequently classified as sub-brown dwarfs. Tea rogue planets That roam our Milky Way can number in the billions.
Nature versus nurture: The strange case of exoplanet “cousins”
The two mismatched “prime” exoplanets, one cloudy and one clear, orbit their yellow dwarf stars once every 4.5 Earth days. Both exoplanets hug their parent star tightly, much more than Mercury hugs our Sun. However, long ago, the planets probably migrated inward into the blazing fires and scorching heat of their stellar father from the more distant regions. distant where they were born.
One planet may have formed differently from the other as a result of a different set of circumstances. “You can say it’s nature versus nurture. Right now, they seem to have the same physical properties. So if their measured composition is defined by their current state, then it should be the same for both planets. But that’s not the case. Instead, it appears their training stories could be playing an important role, “explained study co-investigator Dr. Kevin Stevenson in the June 5, 2017 post. STSI press release.
The clouds of this distant duo of fiery gas giants like Jupiter are not like the clouds we see on Earth. Instead, these very strange clouds are probably alkaline clouds. This means that they are probably made up of molecules like sodium sulfide and potassium chloride. The average temperature on each of these fiery planets is over 1,300 degrees Fahrenheit.
The two exoplanets are also tidally locked. This means that they always show the same side towards their star father. The two worlds have an extremely hot day side and a cooler night side.
The team of astronomers has only just begun to learn what factors are important in making some exoplanets cloudy, in contrast to others that are clear. To better understand what the mysterious past of the planets may have been like, scientists will need future observations with the HST and the one that will soon be released James Webb Space Telescope.
The team’s results were presented on June 5, 2017 at the 230th meeting of the American Astronomical Society in Austin, Texas.
