TESS, the Transitioning Exoplanet Survey, has identified at least eight exoplanets and discovered over 300 candidates eight months after its launch.

The spacecraft which replaced Kepler last year began its two-year scientific mission to survey the night sky for Earth-like planets outside of the solar system in July.

TESS Finds Exoplanet That Is Puzzling Scientists

One of its latest discoveries is a bizarre world that has at least 23 times the mass of Earth. Details of the newfound exoplanet were unveiled on Jan. 7 at a meeting of the American Astronomical Society in Seattle, Washington.

"This is the most extreme system with this type of architecture," stated Xu Chelsea Huang, one of the scientists who is working behind the project at MIT. "We don't know how that could form."

The planet in question is orbiting a dwarf star known as HD 21749 which is located 53 light-years away from Earth. According to scientists, the planet has an outstretched orbit and zips around its star every 36 days.

Based on their calculations, the scientists think that the planet has a surface temperature of about 300 degrees Fahrenheit — the coolest surface temperature for a planet orbiting a similar star. They also believe that the exoplanet is likely mostly rocky with a dense atmosphere.

However, the strangest part of the discovery is the possible second planet that team has also detected orbiting HD 21749. The second exoplanet is even smaller than Earth, which makes it the smallest exoplanet that TESS has discovered so far.

Two other oddball exoplanets were confirmed at the AAS meeting on Monday, Jan. 7: a super-Earth called Pi Mensae c and LHS 3844 b, a planet slightly bigger than Earth.

TESS: Learning About The Universe 

TESS sectioned the night sky into 26 segments — each to be surveyed meticulously over two years. The spacecraft will train its four cameras at each segment for 27 days to look for little momentary dips of starlight that signals the presence of an orbiting exoplanet.

However, unlike its predecessor, the spacecraft's mission is to not only look for exoplanets but also to allow scientists to monitor and study the sudden bursts of distant stars' brightness as a result of a supernova. 

"Based on the brightness and shape of that flare, there's a lot of science that can be done," stated Michael Fausnaugh, an astronomer at MIT. 

TESS is in the process of surveying the southern hemisphere.