Author Topic: Astronomy Thread  (Read 76305 times)

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Re: Astronomy Thread
« Reply #460 on: 06/13/2018 07:52 PM »
ALMA Discovers Trio of Infant Planets around Newborn Star

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Two independent teams of astronomers have used ALMA to uncover convincing evidence that three young planets are in orbit around the infant star HD 163296. Using a novel planet-finding technique, the astronomers identified three disturbances in the gas-filled disc around the young star: the strongest evidence yet that newly formed planets are in orbit there. These are considered the first planets to be discovered with ALMA.

http://www.eso.org/public/news/eso1818/

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Re: Astronomy Thread
« Reply #461 on: 06/14/2018 07:53 PM »
New Constraints on the Abundance and Composition of Organic Matter on Ceres

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Near‐infrared reflectance spectra from the Dawn mission at Ceres were recently found to exhibit a 3.4 μm absorption indicative of the presence of aliphatic organic compounds. Constraints on abundance and composition of these organics are necessary to inform discussions of their origin. We model reflectance spectra of organic‐bearing regions on Ceres using laboratory spectra of insoluble organics of known composition extracted from terrestrial sedimentary rocks (i.e., kerogens) and carbonaceous chondrite meteorites (i.e., insoluble organic matter, IOM). The 3.4 μm aliphatic organic absorptions observed in Dawn near‐infrared data are stronger than those observed in lab spectra of carbonaceous chondrites, and modeling requires 45% to 65% spectral fraction of IOM to fit spectra from Ceres. The spectral fraction of kerogen necessary to fit the same Ceres spectra ranges from 5% to 15% depending on the hydrogen to carbon ratio of the kerogen. Any proposed mechanism of organic delivery or formation on Ceres should explain the presence of highly concentrated IOM or why the composition is distinct from meteorite‐derived IOM if lower organic abundances are considered more plausible.

Plain Language Summary
Organics were recently detected on the dwarf planet Ceres with infrared spectroscopy. The origin of these organics is, as yet, unknown. Using laboratory spectra of terrestrial and extraterrestrial (meteorite‐derived) organic materials with known composition, we reanalyze the Ceres spectra to constrain composition and abundance of those organics. Such constraints could help us discern whether these organics formed on Ceres or were delivered by an impactor.

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL077913

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Re: Astronomy Thread
« Reply #462 on: 06/14/2018 09:25 PM »

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Re: Astronomy Thread
« Reply #463 on: 06/15/2018 06:41 AM »
A dust-enshrouded tidal disruption event with a resolved radio jet in a galaxy merger

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Tidal disruption events (TDEs) are transient flares produced when a star is ripped apart by the gravitational field of a supermassive black hole (SMBH). We have observed a transient source in the western nucleus of the merging galaxy pair Arp 299 that radiated >1.5 ◊ 1052 erg in the infrared and radio but was not luminous at optical or x-ray wavelengths. We interpret this as a TDE with much of its emission reradiated at infrared wavelengths by dust. Efficient reprocessing by dense gas and dust may explain the difference between theoretical predictions and observed luminosities of TDEs. The radio observations resolve an expanding and decelerating jet, probing the jet formation and evolution around a SMBH.

http://science.sciencemag.org/content/early/2018/06/13/science.aao4669

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Re: Astronomy Thread
« Reply #464 on: 06/15/2018 08:02 PM »
Long suspected theory about the Moon holds water

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A team of Japanese scientists led by Masahiro Kayama of Tohoku University's Frontier Research Institute for Interdisciplinary Sciences, has discovered a mineral known as moganite in a lunar meteorite found in a hot desert in northwest Africa.

This is significant because moganite is a mineral that requires water to form, reinforcing the belief that water exists on the Moon.

"Moganite is a crystal of silicon dioxide and is similar to quartz. It forms on Earth as a precipitate when alkaline water including SiO2 is evaporated under high pressure conditions," says Kayama. "The existence of moganite strongly implies that there is water activity on the Moon."

https://www.tohoku.ac.jp/en/press/moon_holds_water.html

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Re: Astronomy Thread
« Reply #465 on: 06/18/2018 08:36 PM »
EXPLOSIVE VOLCANOES SPAWNED MYSTERIOUS MARTIAN ROCK FORMATION

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Explosive volcanic eruptions that shot jets of hot ash, rock and gas skyward are the likely source of a mysterious Martian rock formation, a new study finds. The new finding could add to scientistsí understanding of Marsís interior and its past potential for habitability, according to the studyís authors.

The Medusae Fossae Formation is a massive, unusual deposit of soft rock near Marsís equator, with undulating hills and abrupt mesas. Scientists first observed the Medusae Fossae with NASAís Mariner spacecraft in the 1960s but were perplexed as to how it formed.

https://news.agu.org/press-release/explosive-volcanoes-spawned-mysterious-martian-rock-formation/