[News] After the explanation to the most common planets in the galaxy

[MosterOfficial ☆]

 

 

A survey of exoplanet candidates identified by NASA's TESS mission is laying the groundwork for understanding how the most common worlds in the Milky Way formed and evolved.

The goal of the Carnegie Institution for Science-led research is also to determine why the pattern of planetary orbits and sizes in our Solar System is so unusual.

 

Johanna Teske of Carnegie, Sharon Wang of Tsinghua University (formerly Carnegie) and Angie Wolfgang (formerly of Penn State University and now at SiteZeus), head the Magellan-TESS Survey (MTS), which is in the middle of its planned three-year duration. Their mid-survey findings, in collaboration with a large international group of researchers, will be published in the Astrophysical Journal Supplement Series.

NASA's Kepler mission revealed that our galaxy is teeming with planets, discovering thousands of confirmed worlds and predicting that there are billions more. One of the surprises contained in this reward is that exoplanets between the size of Earth and Neptune are the most common discovered so far, even though there are none in our own Solar System. These "in-between" planets appear to be two different sizes, roughly one to 1.7 (super-Earths) and roughly two to three (mini-Neptune) times the size of Earth, indicating different gas content in his compositions. "We want to understand whether super-Earths and mini-Neptunes were distinct from their earliest origins, or whether some aspect of their evolution caused them to deviate from each other," Teske explained in a statement. "In a sense, we hope to probe the nature-nurturing question for the most common exoplanets in the galaxy: were these planets born differently or did they diverge due to their environment? Or is it something in between?"

 

 

The survey uses TESS data and observations from the Magellan telescopes at Carnegie's Las Campanas Observatory in Chile to study a selection of 30 small, relatively short-period planet candidates. TESS data shows dips in brightness when an object passes in front of its host star. The amount of attenuation allows the survey team to measure the radius of a candidate planet.

This information is combined with observations collected by the Planet Seeking Spectrograph at Las Campanas that works using a technique called the radial velocity method, which is currently the most common way for astronomers to measure the masses of individual planets.

 

The Magellan-TESS study team is interested in the interplay between key variables that could help astronomers better characterize the formation pathways of the super-Earth and mini-Neptune planets. They look for trends in the relationships between the mass of a planet and its radius; the properties of its host star, including the composition and amount of energy it radiates to the planet; and the architecture of the planetary system of which the planet is a part. "The underlying relationship between the radius and the mass of these small planets is crucial in determining their overall compositions, through their overall density, as well as how much variation there is in their compositions," Wolfgang explained. "Quantifying this relationship will help us to discern if there is one training path or multiple pathways." What sets this survey apart from previous work is its scope: the team designed the survey from the ground up to try to account for biases that could skew the way the results are interpreted in a larger context. Your goal is to be able to draw strong conclusions about super-Earths and mini-Neptune planets as a po[CENSORED]tion, versus just a collection of 30 individual objects. The mid-survey findings, which make a significant contribution to the number of small planets with known masses and radii, already point to evidence of small observational selection biases that may have affected scientists' work on mass measurements. Therefore, the MTS could provide an important framework for future radial velocity studies of transiting planets. Going forward, the next half of the survey will focus on completing the sample (this document contains 22 of the 30 planned candidates) and continuing to monitor all systems for longer period planets not detected by TESS to probe the system architectures. Verifying the influence of the host star composition is another next step, as previous work has suggested that the compositions of the planets may be related to those of the stars they orbit.

 

"We hope that obtaining this multidimensional understanding will significantly improve our understanding of exoplanet evolution and perhaps explain why our own solar system seems unusual," concluded Wang.

 

News