from the there-is-a-poop-joke-here-someplace dept.
Scientists have used the Spitzer Space Telescope to find a possible exoplanet or brown dwarf candidate, OGLE-2016-BLG-1190Lb, around 22,000 light years away near the center of the Milky Way galaxy. Spitzer is currently using transit photometry and gravitational microlensing to find exoplanets, a use the telescope wasn't originally designed for. Spitzer recently discovered five of the seven exoplanets around TRAPPIST-1 using the transit photometry method.
OGLE-2016-BLG-1190Lb is likely to be the first exoplanet Spitzer has found in the Milky Way's Galactic bulge using gravitational microlensing. At an estimated 13.4 ± 0.9 Jupiter masses, the object is right near the deuterium burning limit, the boundary dividing large gas giants from brown dwarfs.
The paper explains the significance of the discovery:
The discovery of Spitzer microlensing planet OGLE-2016-BLG-1190Lb is remarkable in five different respects. First, it is the first planet in the Spitzer Galactic-distribution sample that likely lies in the Galactic bulge, which would break the trend from the three previous members of this sample. Second, it is precisely measured to be right at the edge of the brown dwarf desert. Since the existence of the brown dwarf desert is the signature of different formation mechanisms for stars and planets, the extremely close proximity of OGLE-2016-BLG-1190Lb to this desert raises the question of whether it is truly a "planet" (by formation mechanism) and therefore reacts back upon its role tracing the Galactic distribution of planets, just mentioned above. Third, it is the first planet to enter the Spitzer "blind" sample whose existence was recognized prior to its choice as a Spitzer target. This seeming contradiction was clearly anticipated by Yee et al. (2015b) when they established their protocols for the Galactic distribution experiment. The discovery therefore tests the well-defined, but intricate procedures devised by Yee et al. (2015b) to deal with this possibility. Fourth, it is the first planet (and indeed the first microlensing event) for which the well-known microlens-parallax degeneracy has been broken by observations from two satellites. Finally, it is the first microlensing planet for which a complete orbital solution has been attempted. While this attempt is not completely successful in that a one-dimensional degeneracy remains, it is an important benchmark on the road to such solutions.
Astronomers have observed enough planetary transits to confirm the existence of seven "Earth-sized" exoplanets orbiting TRAPPIST-1, an ultra-cool (~2550 K) red dwarf star about 39.5 light years away. Three of the exoplanets are located inside the "habitable zone" of their parent star. These three orbit from 0.028 to 0.045 AU away from the star:
Astronomers using the TRAPPIST–South telescope at ESO's La Silla Observatory, the Very Large Telescope (VLT) at Paranal and the NASA Spitzer Space Telescope, as well as other telescopes around the world, have now confirmed the existence of at least seven small planets orbiting the cool red dwarf star TRAPPIST-1. All the planets, labelled TRAPPIST-1b, c, d, e, f, g and h in order of increasing distance from their parent star, have sizes similar to Earth.
The exoplanets are presumed to be tidally locked. The six closest to TRAPPIST-1 have been determined to be rocky, while the seventh, TRAPPIST-1h, requires additional observations to determine its characteristics due to its longer orbital period.
Mass estimates for the planets range from 0.41 Earth masses (M⊕) to 1.38 M⊕. Radii range from 0.76 Earth radii (R⊕) to 1.13 R⊕.
Spitzer, Hubble, and other telescopes will continue to make observations of the TRAPPIST-1 planetary system, but the best data will likely come from the James Webb Space Telescope (JWST), which is scheduled to launch in late 2018. JWST will allow the atmospheres and temperatures of many exoplanets to be characterized, which will help to settle whether the "habitable zones" of red dwarf stars are actually hospitable.
Here's a website dedicated to the star.
Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1 (DOI: 10.1038/nature21360) (DX)
[Researchers] have a new model for explaining how clouds move and change shape in brown dwarfs, using insights from NASA's Spitzer Space Telescope. Giant waves cause large-scale movement of particles in brown dwarfs' atmospheres, changing the thickness of the silicate clouds, researchers report in the journal Science. The study also suggests these clouds are organized in bands confined to different latitudes, traveling with different speeds in different bands.
"This is the first time we have seen atmospheric bands and waves in brown dwarfs," said lead author Daniel Apai, associate professor of astronomy and planetary sciences at the University of Arizona in Tucson.
[...] "The atmospheric winds of brown dwarfs seem to be more like Jupiter's familiar regular pattern of belts and zones than the chaotic atmospheric boiling seen on the Sun and many other stars," said study co-author Mark Marley at NASA's Ames Research Center in California's Silicon Valley.
Zones, spots, and planetary-scale waves beating in brown dwarf atmospheres (DOI: 10.1126/science.aam9848) (DX)