At night, seven-year-old Miguel likes to talk to his father, Cesar Rubio, about the planets and the stars. “I try to nurture it,” said Rubio, a machinist in Pomona, California, who makes parts for excavation and power generation equipment.
Now, the boy may claim his father also helped discover the planets. Cesar Rubio is one of thousands of volunteers who have participated in Planet Hunters TESS, a NASA-funded citizen science project that looks for evidence of planets beyond our solar system or exoplanets. A way for members of the public to collaborate with scientists. More than 29,000 people worldwide have joined the Planet Hunters TESS effort to help scientists discover the exoplanets.
Planet Hunters TESS has now announced the discovery of two exoplanets in a study published online in the Royal Astronomical Society monthly Notice magazine, listing Rubio and more than a dozen other citizen scientists as co-authors.
These alien planets orbit a star called HD 152843 about 352 light-years away. This star is about the same mass as the Sun, but about 1.5 times larger and slightly brighter.
- Planet B, about the size of Neptune, is about 3.4 times larger than Earth and completes an orbit around the star in about 12 days. The outer planet,
- Planet C, is about 5.8 times larger than Earth, forming it a “sub-Saturn” and orbiting in 19 to 35 days. In our own solar system, these two planets will be in the orbit of Mercury, which is about 88 days.
Nora Eisner a doctoral student in astrophysics at the University of Oxford in the United Kingdom, and lead author of the study said , “Studying them together, both of them at the same time, is really interesting to constrain theories of how planets both form and evolve over time,”
TESS stands for Transiting Exoplanet Survey Satellite, a NASA spacecraft that launched in April 2018. The TESS team used observatory data to identify more than 100 explanations and 2,600 candidates that await confirmation.
Planet Hunters TESS, powered by the Zooniverse website, launched in December 2018, shortly after the first TESS data became publicly available. Volunteers look at graphs showing the brightness of different stars over time.
They notice that one of these plots shows a brief immersion in the brightness and then an upward swing to the original level. This can happen when a planet passes through the face of its star and blocks a small amount of light – an event known as “transit“.
The Planet Hunters project shares plots of each brightness, called “light curves,” with 15 volunteers. In the background of the website, an algorithm collects all of the volunteer’s submissions and finds light curves that multiple volunteers have flagged. Eisner and colleagues then look at the highest-ranked light diagrams and determine which would be better to follow scientifically.
Even in an era of sophisticated computing techniques such as machine learning, a large team of volunteers is a great help to researchers looking for telescopic data. Since researchers cannot fully train computers to detect potential planetary signatures, the human eye is still valuable. Eisner said, “That’s why so many exoplanet candidates have been dropped and why citizen is so great.”
Then, scientists looked more closely and compared the data with their models, they estimated that two transits came from the inner planet and the other from the second, outer planet.
Scientists needed to look at the stars differently to make sure that the transit signals came from the planets and not from any other source, such as whether they received each other, passed asteroids or moved TESS themselves.
They used a device called HARPS-N (the High Accuracy Radial velocity Planet Searcher for the Northern hemisphere) at the Telescopio Nazionale Galileo in La Palma, Spain, as well as an instrument EXPRES (Extreme Precision Spectrometer) an instrument at Lowell Observatory in Flagstaff, Arizona.
Both HARPS and EXPRES look for the presence of planets by checking whether the starlight is “wobbling” because of the planets they orbit. This technique, called the radial velocity method, also enabled scientists to estimate the mass of a distant planet.
While scientists could not get a signal clear enough to pinpoint the planets’ masses, they did have enough radial velocity data to estimate the mass – 12 times the mass of the earth for the planet b and about 28 times the mass of the earth for the planet c. Their measurement validates signals indicating the presence of planets; more data are needed for confirmation of their masses. Scientists are continuing to monitor the planetary system with HARPS-N and hope to get more information about the planets soon.
Researchers will soon be able to see the high-tech equipment that has the atmosphere of these planets and what gases are present in them. NASA’s James Web Space Telescope, launched later this year, will be able to see what kind of molecules the planet’s atmosphere, especially the larger outer planet.
The HD 152843 planets are far too hot and gaseous to support life as we know it, but they are valuable to study as scientists learn about the range of possible planets in our galaxy.
“We’re moving the child in the direction of finding Earth-like planets and studying its atmosphere, and we’re pushing the boundaries of what we can see,” Eisner said.
Among the citizen scientists who classified the HD 152843 light curve as a possible source of planetary orbits, three were invited to join the Planet Hunter Discussion Forum as well as co-authors in the study to announce the discovery of these planets.
One of these citizen scientists is Alexander Hubert, a college student concentrating on mathematics and Latin in Würzburg, Germany, With paln to become a high school teacher. So far, he has classified more than 10,000 light graphs through Planet Hunters TESS.
Würzburg “I’m really grateful that I have the opportunity on Zooniverse to participate in something different.”
Another co-author, Elizabeth Butten of Leuven, Belgium, works in the recovery administration and says that classifying light line curves in Planet Hunters TESS is ” relaxing.” Interested in astronomy since childhood, he was one of the main volunteers at the Galaxy Zoo, an astronomical citizen science project launched in 2007. Galaxy Zoo invited participants to classify the shapes of distant galaxies.
While Baten has become part of more than a dozen published studies through the Zooniverse Project, the new study is Rubio’s first scientific publication. Astronomy is a long-standing interest and something he can now share with his son. The two occasionally visit the Planet Hunters TESS website.
“I feel like I’m contributing, even though it’s only a small part,” Rubio said. “Especially scientific research, it’s satisfying for me.”
NASA collaborates on a variety of citizen sciences across a wide range of universes, from Earth science to the Sun. Anyone in the world can take can participate.
What is an exoplanet ?
An exoplanet is any planet outside our solar system. The orbits of most other stars, but free-floating exoplanets, called rogue planets, the orbits of the galactic center and are untethered to any star.
Most of the exoplanets discovered so far are in a relatively small area of our galaxy, the Milky Way. We know from NASA’s Kepler Space Telescope that there are more planets in the galaxy than stars.
By measuring the size (diameters) and mass (weight) of exoplanets, we can see compositions ranging from very rocky (like Earth and Venus) to very gas-rich (like Jupiter and Saturn). Exoplanets are made up of elements like planets in our solar system, but the composition of their elements may differ.
Some planets may be affected by water or ice, while others may be affected by iron or carbon. We have identified lava worlds covered by molten oceans, puffy planets with styrofoam densities and dense cores of planets still orbiting their stars.
The first exoplanets were discovered in the 1990s and since then we have identified thousands using a variety of detection methods. It is very rare for astronomers to see an exoplanet through the telescope of the way you see Saturn through the Earth’s telescope.
This is called direct imaging, and only a handful of exoplanets have been found this way (and these tend to be young gas giant planets orbiting far away from their star).
Now we live in a universe of explanations. The count of confirmed planets is in the thousands and rising. It came from only a small sample of the galaxy as a whole.
This number could increase to tens of thousands in a decade, as we increase the number of robotic telescopes launched into space and the power of observation.
Most exoplanets are obtained by indirect methods: measuring the dimming of a star that passes through the planet in front, called a transit method, or observing the spectrum of a star for the tell-tale signs of a planet pulling on its star and causing its light to subtly Doppler shift.
Space telescopes have discovered thousands of planets by observing “transit the slight dimming of light from a star when its tiny planet passes between it and our telescopes. Other detection methods include gravitational lensing, the so-called “wobble method”.
But when multiple methods are used together, we can learn important statistics of the entire planetary system without directly depicting the planets directly. The best example so far is the TRAPPIST-1 system, about 40 light-years away, where about seven Earth-sized planets orbit a small, red star.
The TRAPPIST-1 planets have been examined with ground and space telescopes. The space-based studies revealed not only their diameters, but the subtle gravitational influence these seven closely packed planets have upon each other; from this, scientists determined each planet’s mass.
So now we know their masses and their diameters. We also know how much energy radiated by their stars hits the planet’s surface, allowing scientists to estimate their temperature. We can even reasonably estimate the level of light, and if you are standing on any of it, you can guess the color of the sky.
And much remains unknown about these seven worlds including whether they possess atmospheres or oceans, ice sheets or glaciers, it’s become the best-known solar system apart from our own. Planet Hunters
What is Planet Hunters TSS ?
The recently launched Transiting Exoplanet Survey Satellite (TESS) is providing us with a huge amount of data that allows us to search for planets outside our own solar system, including planets that can support life. With your help, we will be able to find planets that will help us understand how these extrasolar systems are formed and evolved over time. The results may come closer to answering our question that we all want to answer: Are we alone in the universe?
Citizen Science Project
NASA’s citizen science projects collaborate between scientists and interested members of the public. Through this collaboration, volunteers (known as citizen scientists) have helped make thousands of important scientific discoveries. Want to work with some real NASA science? Click on one of the projects below to get started. Icon-enabled projects can be done anywhere, anytime, with just a cellphone or laptop.