Author Topic: ESA - Gaia updates  (Read 34185 times)

Offline Star One

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Re: ESA - Gaia updates
« Reply #100 on: 02/15/2017 07:05 PM »
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[Toronto] Using a novel method and data from the Gaia space telescope, astronomers from the University of Toronto have estimated that the speed of the Sun as it orbits the centre of the Milky Way Galaxy is approximately 240 kilometres per second.
In turn, they have used that result to calculate that the Sun is approximately 7.9 kiloparsecs from the Galaxy’s centre—or almost twenty-six thousand light-years.

Using data from the Gaia space telescope and the RAdial Velocity Experiment (RAVE) survey, Jason Hunt and his colleagues determined the velocities of over 200,000 stars relative to the Sun. Hunt is a Dunlap Fellow at the Dunlap Institute for Astronomy & Astrophysics, University of Toronto.

http://www.dunlap.utoronto.ca/missing-stars-in-the-solar-neighbourhood-reveal-the-suns-speed-and-distance-to-the-centre-of-the-milky-way-galaxy/

Offline Star One

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Re: ESA - Gaia updates
« Reply #101 on: 03/06/2017 07:53 PM »
Gaia Data Release 1. Open cluster astrometry: performance, limitations, and future prospects

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Context. The first Gaia Data Release contains the Tycho-Gaia Astrometric Solution (TGAS). This is a subset of about 2 million stars for which, besides the position and photometry, the proper motion and parallax are calculated using Hipparcos and Tycho-2 positions in 1991.25 as prior information. Aims. We investigate the scientific potential and limitations of the TGAS component by means of the astrometric data for open clusters. Methods. Mean cluster parallax and proper motion values are derived taking into account the error correlations within the astrometric solutions for individual stars, an estimate of the internal velocity dispersion in the cluster, and, where relevant, the effects of the depth of the cluster along the line of sight. Internal consistency of the TGAS data is assessed. Results. Values given for standard uncertainties are still inaccurate and may lead to unrealistic unit-weight standard deviations of least squares solutions for cluster parameters. Reconstructed mean cluster parallax and proper motion values are generally in very good agreement with earlier Hipparcos-based determination, although the Gaia mean parallax for the Pleiades is a significant exception. We have no current explanation for that discrepancy. Most clusters are observed to extend to nearly 15 pc from the cluster centre, and it will be up to future Gaia releases to establish whether those potential cluster-member stars are still dynamically bound to the clusters. Conclusions. The Gaia DR1 provides the means to examine open clusters far beyond their more easily visible cores, and can provide membership assessments based on proper motions and parallaxes. A combined HR diagram shows the same features as observed before using the Hipparcos data, with clearly increased luminosities for older A and F dwarfs.

https://arxiv.org/abs/1703.01131

Offline bolun

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Re: ESA - Gaia updates
« Reply #102 on: 04/13/2017 12:23 PM »
Two million stars on the move

12 April 2017

The changing face of our Galaxy is revealed in a new video from ESA’s Gaia mission. The motion of two million stars is traced 5 million years into the future using data from the Tycho-Gaia Astrometric Solution, one of the products of the first Gaia data release. This provides a preview of the stellar motions that will be revealed in Gaia's future data releases, which will enable scientists to investigate the formation history of our Galaxy.

http://sci.esa.int/gaia/59004-two-million-stars-on-the-move/


Offline bolun

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Re: ESA - Gaia updates
« Reply #103 on: 06/10/2017 12:51 PM »
The future of the Orion constellation

9 June 2017

A new video, based on measurements by ESA’s Gaia and Hipparcos satellites, shows how our view of the Orion constellation will evolve over the next 450 000 years.

Stars are not motionless in the sky: their positions change continuously as they move through our Galaxy, the Milky Way. These motions, too slow to be appreciated with the naked eye over a human lifetime, can be captured by high-precision observations like those performed by ESA’s billion-star surveyor, Gaia.

By measuring their current movements, we can reconstruct the past trajectories of stars through the Milky Way to study the origins of our Galaxy, and even estimate stellar paths millions of years into the future.

This video provides us with a glimpse over the coming 450 000 years, showing the expected evolution of a familiar patch of the sky, featuring the constellation of Orion, the Hunter.

http://www.esa.int/Our_Activities/Space_Science/Gaia/The_future_of_the_Orion_constellation


Offline Ben the Space Brit

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Re: ESA - Gaia updates
« Reply #104 on: 06/11/2017 04:31 PM »
That Orion one has one major bit of speculation in it: No-one knows how long Betelgeuse has left!
"Oops! I left the silly thing in reverse!" - Duck Dodgers

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The time for words has passed; The time has come to put up or shut up!
DON'T PROPAGANDISE, FLY!!!

Offline Star One

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ESA - Gaia updates
« Reply #105 on: 07/08/2017 08:54 PM »
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With the help of software that mimics a human brain, ESA's Gaia satellite spotted six stars zipping at high speed from the centre of our Galaxy to its outskirts. This could provide key information about some of the most obscure regions of the Milky Way.

http://sci.esa.int/gaia/59263-artificial-brain-helps-gaia-catch-speeding-stars/

« Last Edit: 07/08/2017 09:04 PM by Star One »

Offline bolun

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Re: ESA - Gaia updates
« Reply #106 on: 08/21/2017 11:03 AM »
Preview of Gaia’s sky in colour

This map is a preview of Gaia’s measurements of the sky in colour.

The image includes preliminary data from 18.6 million bright stars observed by Gaia between July 2014 and May 2016, and it shows the middle value of the colours of all stars that are observed in each pixel. The colour of each star is estimated by comparing the total amount of blue and red light recorded by Gaia.

The Galactic Plane, corresponding to the most densely populated region of our Milky Way galaxy, stands out as the roughly horizontal feature across the image. The reddest regions in the map, mainly found near the Galactic Centre, correspond to dark areas in the density of stars: these are clouds of dust that obscure part of the starlight, especially at blue wavelengths, making it appear redder. It is also possible to see the two Magellanic Clouds – small satellite galaxies of our Milky Way – in the lower part of the map.

Gaia’s first full-colour all-sky map, based on data for more than 1 billion stars, will be unleashed in its highest resolution in April 2018.

Full story: Sneak peek of Gaia's sky in colour

http://www.esa.int/spaceinimages/Images/2017/08/Preview_of_Gaia_s_sky_in_colour

Image credit: ESA/Gaia/DPAC/CU5/CU8/DPCI/F. De Angeli, D.W. Evans, M. Riello, M. Fouesneau, R. Andrae, C.A.L. Bailer-Jones

Online jebbo

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Offline bolun

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Re: ESA - Gaia updates
« Reply #108 on: 12/27/2017 10:35 AM »

Offline Star One

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Tags: gaia