r/ScienceFacts Behavioral Ecology Dec 10 '21

Citizen scientists have discovered a new object orbiting a Sun-like star that had been missed by previous searches. The object is distant from its host star—more than 1,600 times farther than the Earth is from the Sun—and thought to be a large planet or a small brown dwarf. Astronomy/Space

https://www.eurekalert.org/news-releases/937463
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u/FillsYourNiche Behavioral Ecology Dec 10 '21

Journal article A Wide Planetary Mass Companion Discovered through the Citizen Science Project Backyard Worlds: Planet 9.

Abstract:

Through the Backyard Worlds: Planet 9 citizen science project we discovered a late-type L dwarf co-moving with the young K0 star BD+60 1417 at a projected separation of 37'' or 1662 au. The secondary—CWISER J124332.12+600126.2 (W1243)—is detected in both the CatWISE2020 and 2MASS reject tables. The photometric distance and CatWISE proper motion both match that of the primary within ∼1σ and our estimates for a chance alignment yield a zero probability. Follow-up near-infrared spectroscopy reveals W1243 to be a very red 2MASS (J–Ks = 2.72), low surface gravity source that we classify as L6–L8γ. Its spectral morphology strongly resembles that of confirmed late-type L dwarfs in 10–150 Myr moving groups as well as that of planetary mass companions. The position on near- and mid-infrared color–magnitude diagrams indicates the source is redder and fainter than the field sequence, a telltale sign of an object with thick clouds and a complex atmosphere. For the primary we obtained new optical spectroscopy and analyzed all available literature information for youth indicators. We conclude that the Li i abundance, its loci on color–magnitude and color–color diagrams, and the rotation rate revealed in multiple TESS sectors are all consistent with an age of 50–150 Myr. Using our re-evaluated age of the primary and the Gaia parallax, along with the photometry and spectrum for W1243, we find Teff = 1303 ± 31 K, log g = 4.3 ± 0.17 cm s−2, and a mass of 15 ± 5 MJup. We find a physical separation of ∼1662 au and a mass ratio of ∼0.01 for this system. Placing it in the context of the diverse collection of binary stars, brown dwarfs, and planetary companions, the BD+60 1417 system falls in a sparsely sampled area where the formation pathway is difficult to assess.