Needle in a haystack: Astronomers discover rogue planet with low Earth-like mass in our galaxy | The Weather Channel – Articles de The Weather Channel


Representative image.

(NASA Ames / JPL-Caltech / T. Pyle)

A planet that moves away from its solar system and floats in space forever is referred to as a rogue planet. They leave the gravitational pull of their host star and are no longer tied to any star. In a significant breakthrough, a group of astronomers discovered such a planet in our Milky Way, which has the same mass as that of Mars or Earth.

The new planet, named “OGLE-2016-BLG-1928”, has no nearby stars and the distance from the planet to Earth is yet to be confirmed. The research is important because it shows the effectiveness of the microlens technique in detecting rogue planets in space.

Discovering a celestial body is like finding a needle in a haystack. Now imagine spotting an object floating in space that does not emit any light by itself! The Optical Gravitational Lensing Experiment (OGLE) collaboration and the Korean Microlensing Telescope Network (KMTN) collaboration are the two international teams that have undertaken this extremely difficult task of discovering dark matter and other celestial bodies without radiation. About thirty researchers from these two organizations have now discovered this rogue planet.

Microlenses for detecting low mass planets

In the early years of any solar system, some low-mass planets can theoretically escape the star’s gravitational grip. “According to theories of planetary formation, such as the nucleus accretion theory, typical masses of ejected planets are expected to be between 0.3 and 1.0 Earth mass,” the research paper said.

The discovery of such low mass bodies that have been separated from his solar system is done using a technique called a microlens. In the process, two objects are needed: a light source, which could be a bright star at a distance, and a celestial object with sufficient mass to bend the light coming out of that light source.

The planet which has a low mass acts like a lens which bends the light. Astronomers analyze the variation in radiation due to the object to be determined. If the object in front has a low mass, then the amount of bent light remains less and the duration of bending is also relatively less.

According to the study, this discovery has the shortest time scale to date.

Track down the thug

Over the past couple of years, thanks to a lot of research and discovery, our knowledge of exoplanets has expanded and we now know that there are countless rogue planets floating around in space. Theoretically, the numbers run into the trillions in our Milky Way galaxy alone.

Scientists attribute the drift of low-mass planets to the following causes: the dispersion of planets, interactions between stars in a star system, the passage of stellar objects, solid interactions between larger planets that affect larger planets small and the evolution of the host star beyond the main sequence.

Finding low mass rogue planets is difficult because the microlens process occurs for a short time if these planets are small. The microlens event that led to the discovery of this new planet lasted only 41.5 minutes. This is a very short period where you have to get a good amount of data. This is the reason why crucial details like the distance of the planet from the Earth are still unknown.

Previously, four other tiny rogue planets had been discovered during short-lived microlens events. All of these findings put together provide powerful evidence for the existence of many such planets in the Milky Way, the researchers say.

A rogue planet or a stellar object?

Another major challenge for the researchers was to determine whether the detected object was a rogue planet or a stellar object. When the microlens event is short-lived, the presence of a stellate substance is possible and therefore confirmation becomes necessary. Researchers have ruled out the existence of contemporary stars up to a distance of 8 astronomical units, but some planets orbit their stars at a greater distance than this.

The article says this planet was found to be on the verge of current limits for detecting short-scale microlens events. Detection of the event was performed with 15 data points – 11 were from Google and 4 from KMTN – which is considered relatively less.

The study explains that fewer data points means that “the decreasing part of the light curve is not fully covered by the observations.” These figures lead to certain confusions and uncertainties around the characteristics of the event and of the object being a planet. Part of this confusion comes from the star emitting the light itself. However, the researchers concluded that the properties of this event rule out the possibility of flares originating from a background star.

Even though there is some ambiguity about the mass of the object, most of the event properties point to an object with an unsigned Earth-like mass of a stellar friend up to 8 AU.

The potential of rogue planets for the existence of life is zero. However, the study of these planets becomes important to understand the intricacies of space.

Over the next five years, the Nancy Grace Roman Space Telescope, known as the Hubble Monther, will monitor such planets. The extremely powerful telescope will also image exoplanets, examine dark matter, and obtain spectra from the atmosphere of exoplanets as part of its mission. This mission, again, will help astronomers gain a better understanding of solar systems and their evolution.

The study has yet to be published in a peer-reviewed journal, but the preprint can be viewed here.


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Arline J. Mercier

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