Association of Universities for Research in Astronomy
An artist's depiction of a planet. Astronomers have discovered at least 70 new free-floating planets in a nearby region of the Milky Way using observations and archival data from several of the NOIRLab's observatories. Credit: NOIRLab
Astronomers have discovered at least 70 new free-floating planets in a nearby region using observations and archival data from several of the NOIRLab's observatories. This is the largest sample of such planets found in a single group and it nearly doubles the number known over the entire sky.
The Upper Scorpius OB stellar association is home to a group of free-floating planets. Over the course of 20 years of observations, at least 70 and as many as 170 Jupiter-sized planets have been found. The first free-floating planets were discovered in the 1990s, but the latest findings have doubled the number of known planets.
The study's first author, Nria Miret-Roig of the Laboratoire d'Astrophysique de Bordeaux, used archival data from a number of large observatories to find these planets.
Astronomers have discovered at least 70 new free-floating planets in a nearby region of the Milky Way using observations and archival data from several of the NOIRLab's observatories. This is the largest sample of such planets found in a single group and it nearly doubles the number known over the entire sky. Credit: NOIRLab/NSF/AURA/J. da Silva/ESO/L. Calada/N.Risinger.
The discovery of so many free-floating planets would not have been possible without access to NOIRLab's Astro Data Archive and Astro Data Lab, says Hervé Bouy, an astronomer at the Laboratoire d'Astrophysique de Bordeaux.
The data includes images from the NEWFIRM extremely wide-field IR imager at Kitt Peak National Observatory in Arizona and the same instrument that was relocated to theCTIO in Chile.
The treasure trove in the NOIRLab Astro Data Archive has been a fundamental part of the study. We needed very deep and wide-field images in both the optical and near-IR. The Dark Energy Camera and NEWFIRM are among the most sensitive wide-field cameras in the world.
The Dark Energy Camera was designed by the Department of Energy and is one of the highest-performing wide-field imagers in the world. It was built and tested at the DOE's Fermilab and operated by the DOE and the National Science Foundation. The Dark Energy Camera is used for a lot of science. The analysis of the Dark Energy Survey data is supported by the DOE.
The locations of 115 potential free-floating planets recently discovered by a team of astronomer in the direction of the Upper Scorpius and Ophiuchus constellations are highlighted in red circles. The team found between 70 and 170 free-floating planets, which are similar to the planets in our Solar System, but do not circle a star. A number of planet candidates were created in between the two extremes of the study. The credit goes to N.Risinger.
Chris Davis, Program Officer at the National Science Foundation's NOIRLab, says that the project illustrates the importance of providing access to archival data from different telescopes. Over the course of a number of years, the NOIRLab and the CSDC have been working hard to enable this, and continue to do so with support from the NSF.
The planets are located in the Upper Scorpius OB association, which is over 400 light-years away from Earth. The region contains a number of famous nebulae, including the Rho Ophiuchi cloud, the Pipe Nebula, and the Coalsack.
Astronomers watch for a brief chance of an alignment between an exoplanet and a background star when they discover free-floating planets. Microlensing events only happen once, so follow-up observations are impossible.
The new planets were discovered using a different method. These planets are far away from any star that would illuminate them. Miret- Roig and her team took advantage of the fact that the planets are still hot enough to glow in the few million years after they were formed. Miret- Roig's team used 80,000 observations to measure the light of all the members of the association across a wide range of optical and near-infrared wavelengths and combined them with a measurement of how they move across the sky.
"We measured the motions and colors of tens of millions of sources in a large area of the sky," says Miret- Roig. The faintest objects in this region were securely identified by these measurements.
The discovery sheds light on the origin of free-floating planets. Some scientists think that these planets can form from the collapse of a gas cloud that is too small to lead to a star, or that they could have been kicked out of their parent system. Which is the actual mechanism?
There could be more planets that are Earth-sized, according to the ejection model. The planets that are free-floating Jupiter-mass are the most difficult to get rid of.
Vera C. Rubin Observatory is expected to find many more free-floating planets.
A rich population of free-floating planets in the Upper Scorpius young stellar association is the subject of a study. There is a DOI titled " 10.1038/s41550-021-01513-x".
Nature Astronomy journal has information.
The Association of Universities for Research in Astronomy (AURA) provided this.
The largest collection of free-floating planets found in the Milky Way was retrieved on December 26, 2021.
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