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Well over 5,000 planets have been found orbiting other star systems. One of the satellites hunting for them is TESS, the Transiting Exoplanet Survey Satellite. Astronomers using TESS think they are made a rather surprising discovery; their first free-floating – or rogue – planet. The planet was discovered using gravitational microlensing where the planet passed in front of a star, distorting its light and revealing its presence.

We are all familiar with the eight planets in our Solar System and perhaps becoming familiar with the concept of exoplanets. But there is another category of planet, the rogue planets. These mysterious objects travel through space without being gravitationally bound to any star. Their origin has been cause for much debate but popular theory suggests they were ejected from their host star system during formation, or perhaps later due to gravitational interaction. 

Artist impression of glory on exoplanet WASP-76b. Credit: ESA

Simulations have suggested that these ‘free-floating planets’ or FFPs should be abundant in the Galaxy yet until now, not many have been detected. The popular theory of ejection from star systems may not be the full story though. It is now thought that different formation mechanisms will be responsible for different FFP masses. Those FFPs that are high mass may form in isolation from the collapse of gas whilst those at the low mass end (comparable to Earth) are likely to have been subjected to gravitational ejection from the system. A paper published in 2023 even suggests that those FFPs are likely to outnumber those bound planets across the Galaxy!

Detecting such wandering objects among the stars is rather more of a challenge than you might expect. Their limited emission (or reflection) of electromagnetic radiation makes them pretty much impossible to observe. Enter gravitational microlensing, a technique that relies upon an FFP passing in front of a star, it’s gravity then focussing light from the distant star resulting in a brief brightness change as the planet moves along its line of sight. To date, only three FFPs have been detected from Earth using this technique. 

A team of astronomers have been using TESS to search for such microlensing events. TESS was launched in April 2018 and whilst in orbit, scans large chunks of sky to monitor the brightness of tens of thousands of stars. The detection of light changes may reveal the passage of an FFP as it drifts silently in front of the star. It’s not an easy hunt though as asteroids in our Solar System, exoplanets bound to stars and even stellar flares can all give false indications but thankfully the team led by Michelle Kunimoto have algorithms that will help to identify potential targets. 

Illustration of NASA’s Transiting Exoplanet Survey Satellite. Credit: NASA’s Goddard Space Flight Center

The team published their findings recently in the Astrophysical Journal and reported one FFP candidate event associated with the star TIC-107150013 which is 3.2 parsec away. The event lasted 0.074 days +/- 0,002 and revealed a light curve with features expected of a FFP. This marks the first FFP discovered by TESS, an exciting step along the way to start to unravel the mysteries surrounding these strange alien worlds.

Source : Searching for Free-Floating Planets with TESS: I. Discovery of a First Terrestrial-Mass Candidate

The post TESS Finds its First Rogue Planet appeared first on Universe Today.

Almost all moon landers break down during the extraordinary cold of lunar night, but Japan’s Smart Lander for Investigating Moon has astonishingly survived three nights

Almost all moon landers break down during the extraordinary cold of lunar night, but Japan’s Smart Lander for Investigating Moon has astonishingly survived three nights

The very weak forces of attraction caused by the Casimir effect can now be used to manipulate microscopic gold flakes and turn them into a light-trapping tool

The very weak forces of attraction caused by the Casimir effect can now be used to manipulate microscopic gold flakes and turn them into a light-trapping tool

Targeted culling of crown-of-thorns starfish has resulted in parts of the Great Barrier Reef maintaining and even increasing coral cover, leading researchers to call for the programme to be dramatically scaled up

Targeted culling of crown-of-thorns starfish has resulted in parts of the Great Barrier Reef maintaining and even increasing coral cover, leading researchers to call for the programme to be dramatically scaled up

Take a fresh look at the iconic Dumbbell Nebula on occasion of the Hubble Space Telescope's 34 years in space.

Scientists may have discovered how JuMBOs, strangle binary objects found in Orion, may have gone rogue while staying gravitationally bound. The discovery may shake up theories of planet formation.

This is a test – please disregard.

This landscape of “mountains” and “valleys” speckled with glittering stars is actually the edge of a nearby, young, star-forming region called NGC 3324 in the Carina Nebula. Captured in infrared light by NASA’s new James Webb Space Telescope, this image reveals for the first time previously invisible areas of star birth. NASA, ESA, CSA, and STScI

Two spacewalks this winter fixed the power supply of China's Tiangong space station, which was damaged by a space debris strike, state media reported.

Some environmental campaigners claim that attempts to create a circular economy for plastics are doomed to fail – but the arguments can be disingenuous

Some environmental campaigners claim that attempts to create a circular economy for plastics are doomed to fail – but the arguments can be disingenuous

Rivers swelled in southern Russia and northern Kazakhstan in April 2024 following heavy rain and rapid snowmelt. This image shows Orenburg on April 13, the day river levels peaked. This scene was acquired by the OLI-2 (Operational Land Imager) on Landsat 9.

Rivers swelled in southern Russia and northern Kazakhstan in April 2024 following heavy rain and rapid snowmelt. This image shows Orenburg on April 13, the day river levels peaked. This scene was acquired by the OLI-2 (Operational Land Imager) on Landsat 9. NASA/Michala Garrison, USGS

Ural River levels peak in this April 13, 2024, enhanced color image from Landsat 9; here, vegetation appears red, while water is blue-green. After heavy rain and rapid snowmelt, rivers in southern Russia and northern Kazakhstan swelled, flooding homes and displacing thousands of people.

Landsat 9, the latest satellite in the Landsat series, contributes a critical component to the international strategy for monitoring the health and state of the Earth, allowing more frequent observations. Data from Landsat 9 can be used to inform decisions in key areas like urban expansion, coral reef degradation, and natural disasters.

Image Credit: NASA/Michala Garrison, USGS

The U.S. Space Force is testing a new ground-based satellite jamming weapon to help keep U.S. military personnel safe from potential "space-enabled" attacks.

Japan's SLIM lunar lander has now survived three week-long nights on the moon, braving temperatures as low as minus 274 degrees Fahrenheit, despite not being designed to last one!

Using genomic data from more than 9500 species, biologists have mapped the evolutionary relationships between flowering plants

Using genomic data from more than 9500 species, biologists have mapped the evolutionary relationships between flowering plants

Two important barriers to a stable, powerful fusion reaction have been leapt by an experiment in a small tokamak reactor, but we don’t yet know if the technique will work in larger devices