Scientists find an exoplanet whose strange behavior may lead to the Solar's System hidden ninth planet.
- NASA's Hubble Telescope provides 14 years of data on the exoplanet HD106906 b.
- It exhibits strange behavior along its orbit 336 light-year away from Earth.
- Scientists think data from the exoplanet may explain what happened to the possibly hidden Planet Nine in our Solar System.
How many planets are in our Solar System? You may think there's an obvious answer you learned in kindergarten, but the number has fluctuated between 8 and 9, depending on whether you accept Pluto as being large enough for a planet. But there's another mysterious planet that may be lurking at the edge of the Solar System – the so-called "Planet Nine". All we know about it is through inference, arrived at by judging the effects this potential planet may be having on its surroundings. Now, for the first time, scientists measured the motion of a massive exoplanet, in a different solar system, that may be exhibiting behavior similar to that of the hypothesized Planet Nine.
The exoplanet HD106906 b is 336 light-year away from Earth. With the mass of as much as 11 Jupiters, it orbits a double star system. Scientists first discovered it in 2013 but have now been able to get much better information about its orbit thanks to NASA's Hubble Space Telescope. In fact, Hubble has collected 14 years worth of precise data about the exoplanet, allowing for a wealth of new insight.
The exoplanet is located very far from its host stars, 730 times as far as it is from the Earth to the Sun. While its slow 15,000-year-long orbit would ordinarily not allow for very conclusive observation in just 14 years, the Hubble team found that its orbit is extreme, both very inclined and elongated, staying on the outside of a debris disc surrounding the twin stars.
Meiji Nguyen of the University of California, Berkeley, who led the study, commented on how unusual the exoplanet's orbit is:
"To highlight why this is weird, we can just look at our own Solar System and see that all of the planets lie roughly in the same plane," shared Nguyen. "It would be bizarre if, say, Jupiter just happened to be inclined 30 degrees relative to the plane that every other planet orbits in. This raises all sorts of questions about how HD 106906 b ended up so far out on such an inclined orbit."
The Strange Exoplanet That Resembles the Long-Sought “Planet Nine”
How did this planet develop such an orbit? The scientists think it likely formed much closer to the host stars, but the drag from the system's gas disc might have affected its orbit. This could have pushed it closer to the twin stars, whose gravitational force then threw it out into an eccentric orbit, nearly all the way into interstellar space. As the Hubble team's press release explains, a passing star then possibly corrected the exoplanet's orbit and stopped it from leaving the home system altogether.
This explanation is similar to what scientists predict could have pushed the potential Planet Nine to the edges of our Solar System, past the Kuiper belt. Jupiter might have affected its orbit, kicking it out from the inner Solar System. Planet Nine could have kept going past Pluto but a passing star possibly stopped it by altering its orbit.
Paul Kalas of the University of California, Berkeley, a member of the Hubble team, commented that analyzing what happened to exoplanet HD106906 b is like investigating our own past.
"It's as if we have a time machine for our own Solar System going back 4.6 billion years to see what may have happened when our young Solar System was dynamically active and everything was being jostled around and rearranged," elaborated Kalas.
This image, taken by the Hubble Space Telescope, shows one possible orbit (via the dashed ellipse) of the exoplanet HD 106906 b.
Credits: NASA, ESA, M. Nguyen (University of California, Berkeley), R. De Rosa (European Southern Observatory), and P. Kalas (University of California, Berkeley and SETI Institute)
Of course, none of this means we actually found Planet Nine, if it even exists. Evidence for its corporeality includes the strange behavior of small space bodies past Neptune, whose inexplicable orbits might be the result of being affected by the gravitational pull of an unseen planet.
Further investigations into the formation and debris system of the exoplanet HD106906 b will be carried out by the James Webb Space Telescope, slated to launch in October 2021. It promises to shed more like on the exoplanet's unusual system and, by extension, on our own mystery Planet Nine.
Check out the team's paper, published in The Astronomical Journal.
Artist's impression of the possibly hidden "Planet Nine"
Credit: ESA/Hubble, M. Kornmesser
A new study from NASA and the SETI Institute comes up with an exciting number of potentially life-supporting planets.
- A study analyzes data from the Kepler Space Telescope and the European Space Agency's GAIA survey to estimate the number of habitable planets.
- There may be 30 such planets in our own galactic neighborhood.
- The new estimate may help inform future research and missions.
Throughout its nine-year tour of duty that concluded in 2018, NASA's Kepler Space Telescope produced a massive amount of observational data. Scientists are still going through it all. Among its revelations were now-confirmed 2,800 exoplanets, with thousands more still being analyzed. A new study of its data suggests that there may be as many as 300 million inhabitable planets in our galaxy. It finds that several of these could be relatively close by, within 30 light years from here.
Co-author Jeff Coughlin stated in a SETI press release that "this is the first time that all of the pieces have been put together to provide a reliable measurement of the number of potentially habitable planets in the galaxy."
(We previously wrote about a specially designed calculator that determined there could be exactly 36 contactable civilizations.)
What the study finds
Illustration of Kepler-7
The team that produced the new report was led by Steve Bryson of NASA's Ames Research Center in California. The authors of the study looked for stars that are similar in size, age, and temperature to our Sun, between 4,527 to 6,027 °C. These stars are either G dwarfs, or slightly smaller and more plentiful K dwarfs. Next, they looked for planets orbiting such stars that ranged in size from 0.5 to 1.5 times the size of Earth on the assumption that they were most likely to be rocky planets like ours.
A big factor affecting habitability is the ability to support surface water. Earlier estimates of habitable planets have focused primarily on an exoplanet's distance from its sun, the so-called "habitable zone." The new research also takes into consideration the amount of light the planet receives from its sun as a factor in the likelihood of water. The authors of the study supplemented the Kepler data with spectroscopic measurements from the European Space Agency's GAIA survey of a billion stars in the Milky Way.
The stars can be dim enough that their habitable zones are close, causing any exoplanets there to be tidally locked, which means the same side always faces their sun. This makes the stripping off of their atmospheres more likely. One of the unknowns is the degree to which a planet's atmosphere impacts its ability to retain water, though, and for the current research, the authors presumed that atmosphere has a minimal effect on the likelihood of surface water.
Taking all this into consideration, the research "estimate with 95% confidence that, on average, the nearest HZ planet around G and K dwarfs is ∼6 pc away, and there are ∼ 4 HZ rocky planets around G and K dwarfs within 10 pc of the Sun." (pc is the abbreviation for parsec.)
The study offers both a conservative estimate of the number of habitable exoplanets orbiting their stars — 0.37 to 0.60 planets per star — and a more optimistic one: 0.58 to 0.88 per star. More than half of galaxy's suitable stars may have habitable planets.
Refining a search
On a basic level, Coughlin notes, the study means "we're one step closer on the long road to finding out if we're alone in the cosmos."
The research may also prove useful in targeting future study and missions. Says Michelle Kunimoto of the Transiting Exoplanet Survey Satellite group at MIT in Cambridge, Massachusetts, "Knowing how common different kinds of planets are is extremely valuable for the design of upcoming exoplanet-finding missions." She adds that "surveys aimed at small, potentially habitable planets around Sun-like stars will depend on results like these to maximize their chance of success."
Astronomers propose new estimate of Earth-like planets in the Milky Way galaxy.
- Astronomers make new analysis based on data from NASA's Kepler space telescope.
- The researchers estimate there may be as many as six billion Earth-like planets in our galaxy alone.
- The scientists looked for planets that would be able to host life.
Maybe you think one Earth is enough. But what if there were billions? Researchers make a new estimate that the number of Earth-like planets in our Milky Way galaxy can reach us high as 6 billion.
Astronomers at the University of British Columbia (UBC) analyzed data from NASA's Kepler mission to reach the stunning conclusion. The information on 200,000 stars was gathered by the Kepler planet-hunting spacecraft from 2009 to 2018.
The criteria used by the scientists for selecting such a planet maintained it had to be rocky, about the same size as Earth, and orbiting a star like our Sun. This planet also had to be in the habitable zone of its star, where the conditions would be just right to potentially allow for water and life.
UBC researcher Michelle Kunimoto, who co-authored the new study, and previously discovered 17 new planets ("exoplanets") outside our Solar System, said their calculations "place an upper limit of 0.18 Earth-like planets per G-type star." In other words, that's about 5 planets per Sun.
The study's co-author UBC astronomer Jaymie Matthews put this from another perspective, explaining that "Our Milky Way has as many as 400 billion stars, with seven per cent of them being G-type. That means less than six billion stars may have Earth-like planets in our Galaxy."
To conduct the study, Kunimoto utilized a technique known as 'forward modelling,' which allowed her to overcome the issue that Earth-like planets are hard to spot on account of being small and orbiting far from their star.
Legacy of NASA’s Kepler Space Telescope
"I started by simulating the full population of exoplanets around the stars Kepler searched," expounded the researcher in UBC's press release. "I marked each planet as 'detected' or 'missed' depending on how likely it was my planet search algorithm would have found them. Then, I compared the detected planets to my actual catalogue of planets. If the simulation produced a close match, then the initial population was likely a good representation of the actual population of planets orbiting those stars."
While the scientists came up with an impressive number of possible Earths, this likely doesn't mean that's how many such planets there are and if they would have life like ours. But this new estimate definitely expands the possibility that similar planets are out there.
Check out the new study in The Astronomical Journal.
Astronomers spot periodic lights coming from near the black hole at the center of our galaxy.
- Astronomers in Japan observe periodic lights coming from the region near the black hole at the center of our galaxy.
- The twinkling may be produced by hot spots in the accretion disk around the black hole.
- The mysterious region studied features extreme gravity.
Astronomers peered into the heart of our galaxy to reveal surprising lights. Utilizing the ALMA telescope in Chile, a team of Japanese scientists found periodic flickering coming from near the center of the Milky Way, which contains the supermassive black hole Sagittarius A* (Sgr A*). The twinkling is likely due to the rotating radio spots around the black hole, a mysterious region of extreme gravity.
The research team from ALMA, which stands for "Atacama Large Millimeter/submillimeter Array," was led Yuhei Iwata, a graduate student at Keio University, Japan. He explained that the gigantic Sgr A*, with the mass of 4 million suns, has been known to flare up in millimeter wavelengths, infrared light, and X-rays, but this time, the scientists got radio-wave intensity data for a period of 10 days (including 70 minutes per day), and found two specific trends – namely "quasi-periodic variations with a typical time scale of 30 minutes and hour-long slow variations."
Does the black hole itself produce these lights? As far as we know, the black hole doesn't actually make emissions of any sort. The culprits behind the lights are likely hot spots formed in the superhot gas disk surrounding the black hole. It rotates around it, creating an accretion disk.
The astronomers found that the 30-minute variation period of the flickering corresponded to the orbital period of the inner edge of the accretion disk. This discovery provides "compelling insight for the gas motion" around the black hole, stated professor Tomoharu Oka of Keio University, who was also involved in the study.
Michio Kaku: A Black Hole in Our Own Backyard
The research group's other members included Masato Tsuboi of the Japan Space Exploration Agency/The University of Tokyo, Makoto Miyoshi from the National Astronomical Observatory of Japan/SOKENDAI, and Shunya Takekawa of the National Astronomical Observatory of Japan.
Check out their new paper in the Astrophysical Journal Letters.
New study of gamma rays and gravitational lensing points to the possible presence of dark matter.
- Analyzing data from the Fermi Gamma-ray Space Telescope, researchers find hints of dark matter.
- The scientists looked to spot a correlation between gravitational lensing and gamma rays.
- Future release of data can pinpoint whether the dark matter is really responsible for observed effects.
By comparing data derived from gravitational lensing and gamma ray observations by the Fermi Gamma-ray Space Telescope, a study showed that certain regions of the sky emit more gamma rays. While the main cause of this phenomenon may be supermassive black holes, the researchers think that some of the emissions may be because of dark matter. It's a so-far-undetected substance that supposedly takes up as much as 27% of all matter in the Universe, with dark energy taking up another 68% (as per NASA).
The study builds on nine years of gamma-ray data from the Large Area Telescope (LAT) that's part of the Fermi space observatory, and was carried out by Simone Ammazzalorso at the University of Turin in Italy, Daniel Gruen at Stanford University in California, and colleagues.
The data from the telescope previously pinpointed many individual gamma-ray sources, like the remains of supernova explosions or jets of ionized matter called blazars created from accretion of material by supermassive black holes.
While many sources were located, some of the radiation that was detected by the LAT could not be traced. To investigate this, Ammazzalorso and the team of researchers compared gamma-ray background data with the first-year data from the Dark Energy Survey, carried out by the Dark Energy Camera on the Victor Blanco 4-m Telescope in Chile, which took optical snapshots of 40 million galaxies.
The research team was trying to figure out if there's a correlation between the location of gravitational lenses and gamma ray photons. Gravitational lensing measures the distribution of the Universe's matter by utilizing an effect predicted by Einstein. The effect takes place when light traveling to Earth from a distant object is distorted by the gravitational pull of the matter on the way.
The Difference Between Quasars, Blazars, Pulsars and Radio Galaxies
Comparing two sets of data, the scientists realized that regions of the sky with more matter were also responsible for emitting more gamma rays. On the flip side, the regions that were less dense produced fewer gamma rays.
Specifically, the researchers observed this relationship holding at at high energies and small angular scales, as reports Physics World. Blazars were likely the cause of these kinds of gamma ray emissions, according to the physicists.
The scientists spotted a weaker version of this kind of emission at larger angular scales. This other source of the gamma rays was likely dark matter, thinks Francesca Calore, an astroparticle physicist at Annecy-le-Vieux Theoretical Physics Lab in France, who wrote a commentary for the new paper.
"This result is exciting as it marks one of the few hints at the existence of dark matter via indirect detection methods, and it opens up new possibilities for probing dark matter particle models," said Calore.
She warned that there is still a chance the noticed correlation could be due to blazars, which are still not completely understood.
An overlap of gravitational lenses and gamma-ray signals could indicate the presence of dark matter.
Credit: D. Gruen/SLAC/Stanford; C. Chang/University of Chicago; A. Drlica-Wagner/Fermilab
New data that will be released from the Dark Energy Survey, including 100 million galaxies, as well as other upcoming sky research like the Legacy Survey of Space and Time at the Vera Rubin Observatory in Chile should shed more light on the matter.
"With deeper redshift coverage and a better angular resolution, future instruments will enable scientists to better understand the sources behind the universe's gamma-ray glow and, potentially, uncover the nature of dark matter," Calore stated.
Check out the new study in Physical Review Letters.