Astronomers discover a multiplanet system nearby
MIT astronomers have discovered a new multiplanet system that lies just 10 parsecs, or about 33 light-years, from Earth, making it one of the closest known multiplanet systems to our own. The star at the heart of the system likely hosts at least two terrestrial, Earth-sized planets. Credit: MIT News, with TESS Satellite figure courtesy of NASA

One of the closest known multiplanet systems to our own is a system that is just 10 parsecs from Earth.

At the center of the system lies a small and cool M-dwarf star, named HD 260655, and at least two Earth-sized planets have been discovered. The rocky worlds are not likely to be suitable for human habitation as they are too hot to sustain liquid surface water.

Scientists are excited about this system because it is close to its star and will give them a closer look at the properties of the planets.

The two planets in this system are considered among the best targets for atmospheric study because of their star's brightness. There is a question about the atmosphere around these planets. There are signs of water or carbon based species. These planets are great testbeds for exploration.

The discovery will be presented at the meeting of the American Astronomical Society. The team at MIT has members from all over the world.

There's data power.

NASA's Transiting Exoplanet Survey Satellite (TESS), an MIT-led mission, was the first to identify the new planetary system.

Kunimoto, a member of MIT's TESS science team, noticed a pair of dips in starlight, or transits, from the star HD 260655.

She ran the detections through the mission's science inspection and found two objects that were later classified as TESS objects of interest. The same signals were also found by the Science Processing Operations center. The objects are likely to be confirmed by other telescopes.

It can take a long time for the process to confirm new planets. The process was shortened greatly with the help of archival data.

Shporer looked to see if the star was seen before by other telescopes. HD 260655 was listed in a survey of stars taken by the HIRES, an instrument that operates in Hawaii. Researchers were able to access the survey's publicly available data because HIRES had been monitoring the star since 1998.

HD 260655 is an instrument that works in the Calar Alto Observatory in Spain. The team wanted to combine their data power by reaching out to members of both HIRES and CAR MENES.

Shporer says that the negotiations are sometimes delicate. The teams were able to work together. The human interaction is crucial in getting the data.

The planetary pull is performed.

The collaborative effort quickly confirmed the presence of two planets around HD 260655.

The researchers looked through the data of the star to confirm that the signals from TESS were from two planets. The surveys measure a star's radialvelocity.

Kunimoto says that every planet around a star will have a pull on it. A planetary-mass object tugging on a star is what we are looking for.

Shporer said they knew they had something exciting.

The team used TESS data to pin down the properties of both planets. The inner planet, known as HD 260655b, is 1.2 times the size of the Earth, according to their findings. HD 260655c is 1.5 times as big as the Earth and is the second planet outside of our solar system.

The researchers were able to calculate the planet's mass from the radial-velocity data. The inner planet is larger than the Earth and the outer planet is smaller. The team calculated each planet's density from their size and mass. The smaller planet is denser than the larger planet. Based on their density, both planets are probably rocky.

The researchers estimate that the surface of the inner planet is around 700 kelvins, while the outer planet is around 500 K.

It's too hot for liquid water to exist on the surface.

There could be more planets in the system. There are many multiplanet systems that are home to five or six planets. We will hopefully find more, and one might be in the right place. That's a good way to think.

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