Stellar 'swarms' help astronomers understand the evolution of stars

August 28, 2018, Carnegie Institution for Science
Credit: CC0 Public Domain

New work from Carnegie's Jonathan Gagné and the American Museum of Natural History's Jacqueline Faherty identified nearly a thousand potential members and 31 confirmed members of stellar associations—stars of similar ages and compositions that are drifting together through space—in our own corner of the Milky Way. Their work, published in the Astrophysical Journal, could help astronomers understand the evolution of stars and the properties of future exoplanet discoveries.

"Like a swarm of birds flying together in the sky, the common velocities of stars in an association tell us that us that they are related," Gagné explained. "This teaches us something about their age and their compositions,"

Thanks to internal similarities between group members and external differences between different groups—particularly when it comes to member ages—astronomers can use stellar associations to glean information about the history of star formation in our corner of the Milky Way. These stars' ages vary from a few million to a billion years old, depending on the group, a range that offers astronomers a sweeping view of among our neighbors.

Gagné and Faherty combed through data from the European Space Agency's three-dimensional mapping mission of our galaxy, Gaia, which was released earlier this year, to discover this goldmine of confirmed and potential .

"Our sample is mostly comprised of stars called red dwarfs, which are smaller than our Sun and relatively cool," Gagné said. "Because of their size, they can be difficult to observe, although we know that they are extremely common in the galaxy, which is why the Gaia data is such a great windfall."

Credit: Visualization rendered by Dan Tell from the California Academy of Sciences using SCISS Uniview software and directed/written by Jackie Faherty from the American Museum of Natural History.

What they learn about these stars could also inform astronomers' understanding of planets or planet-like objects found within their associations by upcoming space-based missions.

"If future missions like NASA's Transiting Exoplanet Survey Satellite, or TESS, are able to find exoplanets orbiting our , the information we've gathered about their ages based on their membership in one of these associations, will be able to teach us a great deal about what planetary system evolution looks like at different points in time," added Faherty, who is a Carnegie alumna.

In addition to the bonanza of red dwarf members of neighboring stellar associations, Gagné and Faherty discovered 111 that are part of these local associations. Brown dwarfs are sometimes called failed stars or super Jupiters. They're smaller than —too small to sustain the hydrogen fusion process—but more massive than giant planets. As such, they provide a natural link between astronomy and planetary science and are of great interest to scientists.

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7 comments

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Nik_2213
4.5 / 5 (2) Aug 28, 2018
And no onward link ?
Sad...
jonesdave
3.9 / 5 (11) Aug 28, 2018
And no onward link ?
Sad...


After some searching, I'm guessing this is it;

BANYAN. XIII. A First Look at Nearby Young Associations with Gaia Data Release 2
Gagne, J & Faherty, J. K.
http://iopscience...7/aaca2e
Nik_2213
5 / 5 (7) Aug 28, 2018
Thank you, thank you. Although that article is pay-walled, it led me to...
https://arxiv.org...1715.pdf

I've had a passion for nearby stars' exoplanets since the BIS Daedalus Project. I remember how Van de Kamp's early candidates were cruelly dashed by the discovery of instrument error...
cantdrive85
1.4 / 5 (10) Aug 28, 2018
Like a swarm of birds flying together in the sky, the common velocities of stars in an association tell us that us that they are related," Gagné explained. "This teaches us something about their age and their compositions,"

It tells us they are likely powered by the same Birkeland current.
rrwillsj
5 / 5 (2) Aug 29, 2018
Sorry cant but you are confusing a Planetary phenomena of Birkeland currents with different Galactic Phenomena. The Birkland currents do not scale up to interstellar proportions. But rather are a very local cause and effect.

It's like students learning about magnets. Then imagining that a very local repellent effect can be scaled up to lift and propel a flying car. Only on F/x'ed youtube videos.

Oh, and their mothers want their pie pans returned!
cantdrive85
2.3 / 5 (3) Aug 30, 2018
Plasma processes are in fact scalable, galactic size Birkeland currents are well within applicability of this scalability. Not only do Birkeland currents scale to interstellar proportions but they also scale up to intergalactic proportions, they are what power galaxies.
rrwillsj
not rated yet Aug 30, 2018
Well cant, I don't see the possibility but this wouldn't be the first time I guessed wrong.

What analysis are you basing your assumptions upon? I like the taste of crow. Feed me supporting data and confirming research.

"Similar" is not "equivalent". Speculations are a dime a dozen. Stellar "clouds" of dust and plasma are not the same as atmospheric "clouds" of water vapor.

This conflation of language is something I have been complaining about for many years.

The use of terms such as 'clouds', blackhole', dark matter/energy, and a multitude of similar abuses of the Britanerican language.

Are a combination of unimaginatively sloppy shorthand descriptions for still poorly understood phenomena. And the need for clickbait headlines to grab the mayfly attention of the public.

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