Author Topic: ESA - Gaia updates  (Read 46523 times)

Offline Star One

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Re: ESA - Gaia updates
« Reply #160 on: 05/03/2018 07:53 PM »
Evidence for Unresolved Exoplanet-hosting Binaries in Gaia DR2

Quote
This note describes an effort to detect additional stellar sources in known transiting exoplanet (TEP) systems, which are unresolved or barely resolved in the Gaia Data Release 2 (DR2) catalog (Gaia Collaboration et al. 2016, 2018). The presence of multiple unresolved stars in photometric and spectroscopic observations of a transiting planetary system biases measurements of the planet's radius, mass, and atmospheric conditions (e.g., Buchhave et al. 2011; Evans et al. 2016; Southworth & Evans 2016). In addition to the effect on individual planetary systems, the presence of unresolved stars across the sample of known exoplanets biases our overall understanding of planetary systems, due to the systematic underestimation of both masses and radii (Ciardi et al. 2015).

http://iopscience.iop.org/article/10.3847/2515-5172/aac173/meta

Offline Star One

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Re: ESA - Gaia updates
« Reply #161 on: 05/07/2018 07:45 PM »
Gaia Reveals Evidence for Merged White Dwarfs

We use Gaia Data Release 2 to identify 13,928 white dwarfs within 100 pc of the Sun. The exquisite astrometry and photometry from Gaia reveals for the first time a bifurcation in the observed white dwarf sequence in both Gaia and the Sloan Digital Sky Survey passbands. The latter is easily explained by a helium atmosphere (DB) white dwarf fraction of 36%. However, the bifurcation in the Gaia passbands cannot be explained by DB white dwarfs. We simulate theoretical color-magnitude diagrams for single and binary white dwarfs using a population synthesis approach and demonstrate that the only way to explain the bifurcation in the Gaia data is through a significant contribution from single white dwarfs that formed through mergers. This is the first direct detection of such a population in the solar neighborhood.

https://arxiv.org/abs/1805.01227

Offline AegeanBlue

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Re: ESA - Gaia updates
« Reply #162 on: 05/10/2018 09:09 PM »
Spain's contribution to Gaia DPAC:

https://www.res.es/en/news/gaia-creates-richest-star-map-our-galaxy-participation-two-res-nodes

There is also a large number of discoveries coming out of GaiaDR2. A twitter search for the hashtag #GaiaDR2 reveals quite a number of papers out. New stellar streams, new open star clusters, error margins in the DR2 parallaxes and other stuff. The typical method seems to be run a script on DR2, pull out interesting stars, cross check with other catalogs or at best a couple of days of observations and then publish your findings.

Offline philw1776

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Re: ESA - Gaia updates
« Reply #163 on: 05/15/2018 04:45 PM »
Generic public article on early Gaia papers & results...
https://www.sciencenews.org/article/gaia-delivers-trove-data-revealing-secrets-milky-way

Couple of favorites interesting to me...

Improved radii for Kepler stars & exoplanets
https://arxiv.org/abs/1805.00231


Better Cepheid distances and problems with cosmic expansion rates
https://arxiv.org/abs/1804.10655

"Including the DR2 parallaxes with all prior distance ladder data raises the current tension between the late and early Universe route to the Hubble constant to 3.8 sigma (99.99 %)."
“When it looks more like an alien dreadnought, that’s when you know you’ve won.”

Offline Star One

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Re: ESA - Gaia updates
« Reply #164 on: 05/18/2018 03:42 PM »
ESA Euronews: Gaia’s revolution in astronomy


Tags: gaia