With the help of data from NASA’s TESS satellite, the Spitzer Space Telescope and the Canary Islands Telescope (GTC), an international team of astronomers have discovered what may be the first complete planet, which is located around a star orbiting the sun, Just like the sun, but now smaller than exoplanets. The Canarias Institute of Astronomy participated in this discovery.
Researchers from the Canarias Institute of Aeronautics and Astronautics (IAC) and other international centers have discovered that a planet orbits a white dwarf star, which is a dense remnant similar to our star.In order to make a discovery, published in the magazine today natural, Observations from NASA’s TESS satellite, the decommissioned Spitzer space telescope and Gran Telescopio Canarias (GTC) have been used.
Jupiter-sized object called 1856sAbout seven times as large as a white dwarf WD 1856 + 534, Only 40% larger than the earth. The exoplanet orbits it every 34 hours, which is more than 60 times faster than Mercury orbiting the sun.
He pointed out: “In some way, WD 1856 b was very close to its white dwarf and managed to stay in one piece.” Andrew Vanderbilt, Assistant Professor of Astronomy at the University of Wisconsin-Madison (USA), and lead author of the paper.
“The process of producing white dwarfs destroys nearby planets. Then, anything that is too close is usually torn apart by the star’s huge gravity. “We still have a lot of questions about how WD 1856 b gets to its current position without encountering one of its destinations. Doubt,” he added.
TESS detected WD 1856 b WD at approximately 80 light years in the Draco constellation. It orbits a calm, calm white dwarf star with a diameter of about 18,000 kilometers, possibly as long as 10 billion years, and is a distant member of the three-star star system.
When a sun-like star runs out of fuel, it expands to hundreds or thousands of times its original size, forming a cool red giant star. Subsequently, it expelled the outer layer of gas, losing 80% of its mass, and the remaining hot core became a white dwarf.
“During this process, any nearby objects are swallowed and incinerated. In this system, its current orbit will include WD 1856 b. For this reason, astrophysicists estimate that possible planets must originate from a distance away. At least 50 times the distance from the current position.” Felipe Murgas, IAC researchers and co-author of the article.
“We have known for a long time that after white dwarfs are born, small objects (such as asteroids and comets) will fly toward these stars. Usually, they are separated by the strong gravity of the white dwarf and become a pile of debris,” he explained. Siyi Xu, Assistant astronomer at the Gemini Observatory in Hilo, Hawaii.
“That’s why I was very excited when Andrew told me about this system. We have seen signs that these planets may also scatter inwards, but this seems to be the first time we have seen what makes the whole journey complete. Planets,” he added.
Several possible ways to the stars
The research team has proposed several possible options for pushing WD 1856 b onto an elliptical path around the white dwarf. As the stellar gravity stretches the object, the trajectory will become more rounded over time, creating huge tides to dissipate its orbital energy.
He explained: “The most likely scenario involves several other Jupiter-sized objects that are close to the original orbit of WD 1856 b.” Enric Pallé, IAC researcher and co-author of the article.
Other possible scenarios also consider the gradual gravity of the other two stars in the system (red dwarf stars G229-20 A and B) over a period of billions of years, and the passing of rogue stars destroying the system. However, these and other explanations are unlikely because they require very special conditions to achieve the same effects as possible companion giant planets. ”
Jupiter-sized objects occupy a wide range of masses, from planets that are only a few times larger than Earth to low-mass stars that are thousands of times larger than Earth. The others are brown dwarfs, located between planets and stars.
Scientists usually turn to observing radial velocity to measure the mass of objects, which can indicate the composition and properties of objects. This method works by studying how orbiting objects pull their stars and change the color of their light.
But in this case, the white dwarf is so old that its light has become weak and weak, and scientists cannot detect any significant changes. To overcome this difficulty, the team used Spitzer to observe the system in infrared only a few months before disassembling the telescope.
Brown dwarfs or low-mass stars emit their own infrared light. This means that Spitzer will record brighter flights than the object is a planet that blocks all light.
When the researchers compared the Spitzer data with the visible light transmission observations made by the Gran Telescopio Canarias installed at the Roque de los Muchachos observatory (Garavia, La Palma), they found no significant differences.
Combining the age of the star and other information about the system, they concluded that WD 1856 b is most likely a planet with a mass no more than 14 times the mass of Jupiter. Future research and observations can confirm this conclusion.
“Since the white dwarfs hardly emit light and the flight lasts about 8 minutes, obtaining data from the flight to allow the depth of the flight to be measured with high accuracy is a challenge for many current instruments. He pointed out that fortunately Yes, GTC and his team are able to implement this measure, which is critical to this discovery. Hannu Parviainen, IAC researchers and co-author of the article.
Spanish Japanese Musical Instruments
However, not only large telescopes were used for this work, but also the instruments of the Japanese-Spanish project MuSCAT2 were also installed in Carlos Sanchez Telescope The help of the Ted Observatory (1.52 m) established the limit of the propagation depth at different wavelengths.
The discovery of a world that might orbit a white dwarf star led researchers to consider the significance of studying the atmosphere of a small rock world under similar circumstances. This is because the tiny size of white dwarfs makes it easy to characterize the Earth’s atmosphere.
For example, if an Earth-sized planet is within the orbital distance of WD 1856, there may be water on the surface. Astrophysicists have calculated that NASA’s upcoming James Webb Space Telescope can detect water and carbon dioxide in these imaginary worlds by observing only five transits.
There is currently no evidence that there are other worlds in the system, but there may be other planets that have not yet been discovered. Their orbits may exceed the time that TESS observes a sector, or they may tilt in such a way that no crossing has occurred. White dwarfs are also so small that they cannot capture the transition opportunities of planets that are farther away in the system.
Andrew Vanderburg and others. “A candidate for a giant planet through a white dwarf”, natural, 2020. DOI: https://www.nature.com/articles/s41586-020-2713-y