Questions tagged [gaia]

Questions about the space observatory GAIA.

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1answer
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Gaia/Hipparcos overlap

Is there any kind of concordance available between the sources in the Hipparcos catalog and the Gaia DR2 catalog? I.e., mapping the Gaia DR2 source_id to the Hipparcos HIP number?
4
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1answer
181 views

Distance to Proxima Centauri (Gaia VS New Horizons parallax program)

The current best parallax measurement for the nearest star to the Solar System, Proxima Centauri, has been given by the European Space Agency's Gaia mission. This is $768.5004\; \pm \; 0.2030 \; mas$ (...
14
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2answers
3k views

Why not send a Gaia-like mission to Mars?

This answer to the question why we didn't send Gaia to Neptune's orbit raises the question of why we don't send a Gaia-like mission to the orbit of Mars. It seems like it doesn't have the problems ...
40
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5answers
9k views

Why is Gaia operating around Earth orbit? Why not send it to Neptune's orbit?

Gaia is an astrometry spacecraft that's currently operating around the Sun-Earth L2 Lagrangian point. Question: why here? Why not the Sun-Neptune L2 Lagrangian point? By orbiting the Sun at a larger ...
3
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0answers
46 views

Why is it hard to reconcile Gaia DR2 with the HIP data set

I'm trying to get a database of about 20 million of the brightest stars in the sky for a project I'm working on, and I want to reconcile it with the Hipparcos data set. Currently, I'm only using the ...
4
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1answer
216 views

Obtaining TESS input catalog (TIC) IDs for Gaia `source_ids`?

The TESS input catalog (TIC) "uses the GAIA DR2 catalog as a base" according to the catalog's website. The Gaia DR2 database provides source_ids for each ...
1
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1answer
120 views

How can GAIA's accuracy for position, parallax, and annual proper motion for a given star be the same number?

Per Wikipedia's Gaia (spacecraft); Objectives: Determine the position, parallax, and annual proper motion of 1 billion stars with an accuracy of about 20 microarcseconds (µas) at 15 mag, and 200 ...
2
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1answer
53 views

What has GAIA found out about the dwarf galaxy heritage of stars in the Milky Way, if anything?

I ran across the image below in the August 2000 ESA Bulletin # 103 GAIA – Unravelling the Origin and Evolution of Our Galaxy Figure 3. This simulation shows how a galaxy halo, like our own, may ...
7
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1answer
168 views

Is there an optimum orbit for a hipparcos/GAIA-like parallax observatory

The GAIA spacecraft is currently mapping the stars in the Milky Way by parallax. It orbits in the Earth-Sun L2 lagrange point. The parallax observed from the spacecraft orbiting around the sun allows ...
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0answers
76 views

Plotting GAIA barycentric radial velocity data with python

Does anybody know of a good tutorial on how to use python and astropy to generate plots of GAIA, RAVE or any other database of barycentric (heliocentric) radial velocity data of stars in our galaxy? ...
3
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1answer
205 views

Why no Polaris distance in GAIA DR2?

Querying GAIA DR2 for Polaris (for example using https://gea.esac.esa.int/archive/) yields empty parallax columns. Anyone knows why it was not measured/published?
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0answers
109 views

How to calculate the various properties of a star?

I am wanting to plot a velocity profile (a plot of velocity against the star's distance from the galactic core) from the Gaia DR2, but so far my efforts have been disappointing. The information I ...
3
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1answer
404 views

Gaia Gbp - Grp: why does it get larger as star gets redder?

As an enthusiastic amateur scientist, I'm plowing my way through a cool Gaia DR2-based paper, "An Empirical Measurement of the Initial-Final Mass Relation with Gaia White Dwarfs". I'm doing all right, ...
6
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4answers
1k views

What is the proper interpretation of a negative parallax?

The Gaia data release 2 dataset has some parallaxes listed as negative. What is the proper interpretation of this? Should they be discarded as bad data? Use their absolute value to calculate the ...
4
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1answer
330 views

Very near GAIA DR2 sources - has Proxima Centauri been dethroned?

I made an extract of GAIA DR2 data for parallaxes greater than 500mas. Surprisingly I see a very significant number of sources with parallax greater that 1000, making them much closer than Proxima. ...
2
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2answers
140 views

How many GAIA Data Release 2 files are there?

I am using this index page to download GDR2 data files. http://cdn.gea.esac.esa.int/Gaia/gdr2/gaia_source/csv/ But it keeps giving a different number of links. Sometimes it shows 16,000 files, ...
2
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0answers
155 views

Open cluster membership determination via parallaxes

I'm working in my final course project and I'm using the recently released GAIA DR2 data. I want to determine open clusters membership and I know this has mainly been done using proper motions and ...
2
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1answer
55 views

How is interstellar gas density mapped from GAIA data?

I found the image below in Space.com's article This 3D Color Map of 1.7 Billion Stars in the Milky Way Is the Best Ever Made. The caption for this image reads: The Gaia spacecraft gathered ...
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0answers
46 views

What a grating on GAIA RVS spectroscope?

What size of the grating on GAIA RVS spectroscope ? How many lines on mm, or what defraction angle for 850 nm wavelenth light ? I find some more details here: http://sci.esa.int/gaia/44092-gaia-rvs-...
1
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0answers
165 views

Photometry data from Gaia

I am trying to get data from Gaia. Especially for Cepheids or RR Lyrae. On Gaia websites it say they have released some of the data however I cannot find it. I am looking for two columns with time and ...
2
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0answers
173 views

A question about using both the Simbad and the Gaia archive

It seems a bunch of people, including myself, have got it into our heads to create a 3D visualisation of the stars around us - one where you get to fly around them rather than view them from the ...
4
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1answer
256 views

Gaia Parallax data

When the Gaia parallax data (especially for Cepheid stars) become accessible to public? If it is already released for some parts, where can I find it?
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2answers
596 views

Did Gaia actually generate complete light curves for 212 Cepheids in other galaxies?

The recent BBC news item Gaia clocks speedy cosmic expansion says that a recent Gaia measurement of 212 Cepheid variables in other galaxies within the local group yields a Hubble constant of ~73 km/s/...
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3answers
782 views

Calculating the distance of objects using the Gaia DR1

The Gaia DR1 was released middle of September with ~1.1 billion objects. The schema contains right ascension, declination and parallax, which could be used to calculate Cartesian co-ordinates (xyz). ...
4
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1answer
171 views

How would a small TCO (temporarily captured orbiter) or other natural Earth satellite most likely be detected?

A sentence from the abstract of The population of natural Earth satellites states: At any given time there should be at least one NES of 1-meter diameter orbiting the Earth. The average temporarily-...
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3answers
663 views

Why does Gaia use only calcium NIR lines for stellar radial velocity measurements?

I was reading this overview article about the Gaia spacecraft and I saw the following statement: These spectra provide radial velocity information that are used to study the kinematic and dynamic ...
4
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1answer
215 views

Will Gaia detect inactive neutron stars?

Will the astrometric precision of the Gaia space telescope be able to detect the gravitational influence of cold old solitary neutron stars on the movements of stars? At least in a statistical sense ...