Tuesday, August 17, 2021

The first 3D map of stars around the Sun

Astronomers and citizen scientists have produced the most comprehensive 3-dimensional map of cool brown dwarfs in the cosmic neighborhood of our solar system

Thanks to the work of hundreds of astronomers and the discoveries of thousands of volunteers from the Backyard Worlds: Planet 9 citizen science project, a team of scientists has succeeded in reproducing the most complete map to date of brown dwarfs near our Sun. 

The cartographic work includes up to 525 brown dwarf stars and includes 38 new stars reported for the first time. The results confirm that the Sun's neighborhood is surprisingly diverse relative to other parts of the galaxy.

Thus, with the invaluable help of legions of volunteer citizen scientists from the Backyard Worlds: Planet 9 platform, an international team of astronomers has just announced an unprecedented census of 525 that collects a total of 525 brown dwarfs located less than 65 years old. light of our position in the Universe.

From the results, which are collected in an article presented for publication in The Astrophisical Journal Supplements under the title The Field Substellar Mass Function Based on the Full-sky 20-pc Census of 525 L, T, and Y Dwarfs astronomers have constructed a 3D map of the distribution of cold brown dwarfs in the local neighborhood of the Sun.

The advance was based on an unpublished set of data published by the DESI Legacy Imaging Surveys, which has resulted from combining data from a wide variety of sources such as archival images from the Nicholas U. Mayall 4-meter Telescope at the Observatory. National Kitt Peak -KPNO-, the 4-meter VĂ­ctor M. Blanco Telescope at the Cerro Tololo Inter-American Observatory -CTIO-, both NSF NOIRLabde programs, and the Wide-field Infrared Survey Explorer (WISE) sky maps from NASA. These extensive data sets were combined with new measurements from NASA's Spitzer Space Telescope to create the best three-dimensional map of the Sun's local neighborhood to date.

Brown dwarfs are also known as "failed stars." It is believed that they are formed in the same way as other stars, but they do not have enough mass to trigger nuclear fusion in their nuclei. Their relatively small size and faint brightness make them difficult to identify without careful analysis of data obtained by advanced telescopes, which has led to the lack of news about many of them so far. However, from studying brown dwarfs, astronomers can learn more about star formation and also about planets.

Dwarf stars

Stars and brown dwarfs are classified by their temperature and other spectral characteristics, using letters of the alphabet. For example, our Sun is a G star, a K star is considered an orange dwarf star, and M stars are often called red dwarfs. Meanwhile, brown dwarfs are classified as L, T, and Y dwarfs. Previous studies have revealed that collectively, the four closest star systems to the Sun include a G-dwarf star, a K dwarf, two M dwarfs, and an L dwarf. a T dwarf, and a Y dwarf.

Photo: ESA / Map of brown dwarfs in the solar neighborhood.

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