The Gaia catalogues are star catalogues created using the results obtained by Gaia space telescope.
The catalogues are released in stages that will contain increasing amounts of information; the early releases also miss some stars, especially fainter stars located in dense star fields. [1] Data from every data release can be accessed at the Gaia archive. [2]
The Initial Gaia Source List (IGSL) is a star catalogue of 1.2 billion objects created in support of the Gaia mission. The mission should have delivered a catalogue based entirely on its own data. For the first catalogue, Gaia DR1, a way was needed to be able to assign the observations to an object and to compare them with the objects from other star catalogues. For this purpose, a separate catalog of objects from several other catalogues was compiled, which roughly represents the state of knowledge of astronomy at the beginning of the Gaia mission. [3]
The Attitude Star Catalog is a subset of the IGSL, required for the first approximation in the iterative evaluation of the Gaia data. A first version was created in 2013, a more refined version in April 2014. In total, the Attitude Star Catalog contains 8,173,331 entries with information on position, proper motion and magnitude. [4] Starting with Gaia DR2, the Attitude Star Catalog was replaced with a new list generated from the Gaia Main Data Base (MDB), using the same criteria.
IGSL contains a list of about 200 stars of different spectral classes and magnitudes needed for calibration of the photometric measurements. It is the result of the Gaia Spectrophotometric Standard Stars Survey (SPSS), a selection of stars using Earth-based data in advance of the Gaia mission. Previous catalogues for calibrating magnitudes could not be used for the mission because many of these objects are too bright for Gaia to detect. It was anticipated that some of the stars selected may be previously unrecognized doubles or variable stars that would need to be deleted from the catalogue; for this reason the list contains more stars than necessary. [5] [6] For Gaia EDR3 (Early Data Release 3), a selection was made from more than 100,000 objects that were used for the calibration. These are well-observed objects selected according to Stetson Secondary Standards, but only Gaia data were used. [7]
A list of quasars based on the Large Quasar Astrometric Catalog was prepared for IGSL. This in turn goes back to the Sloan Digital Sky Survey. From the more than one million objects, a selection of 150,000 quasars was made, which are in the region of Gaia's magnitude limit. The selected objects are already well observed and documented. In most cases, quasars are very far away, so that their proper motions and parallaxes are negligibly small. [8] [9]
Gaia Ecliptic Pole Catalogue (GEPC) was created for measuring the poles. The southern part of the catalogue was compiled from observations made with the MPG/ESO telescope at the Max Planck Institute for Astronomy in La Silla, Chile. It contains precise positions, UBV I photometry for the southern field and the corresponding magnitudes. The northern part was created with the Canada–France–Hawaii Telescope on Mauna Kea, Hawaii.
The GEPC v3.0 catalogue contains 612,946 objects from a field of one square degree each at the north and south poles. The north pole is relatively sparse and contains 164,468 objects, while the south pole is still in the region of the Large Magellanic Cloud and contains 448,478 objects. [10] The GEPC data was needed right at the beginning of the mission for the initial calibration. The commissioning phase of the Gaia space probe ended on July 18, 2014. This was followed by a calibration phase of 28 days, during which the ecliptic poles were measured intensively. During this time, Gaia was operated in Ecliptic Poles Scan Law mode (EPSL), in which the two poles were measured twice during each revolution. The initial catalogue was used for Gaia DR1 to match Gaia-found objects to previous star catalogues.
Gaia DR1, the first data release based on 14 months of observations made through September 2015, took place on 13 September 2016. [11] [12] It includes "positions and magnitudes in a single photometric band for 1.1 billion stars using only Gaia data, positions, parallaxes and proper motions for more than 2 million stars" based on a combination of Gaia and Tycho-2 data for those objects in both catalogues, "light curves and characteristics for about 3000 variable stars, and positions and magnitudes for more than 2000 extragalactic sources used to define the celestial reference frame". [13] [14]
The second data release (DR2), which occurred on 25 April 2018, [15] [16] is based on 22 months of observations made between 25 July 2014 and 23 May 2016. It includes positions, parallaxes and proper motions for about 1.3 billion stars and positions of an additional 300 million stars in the magnitude range g = 3–20, [17] red and blue photometric data for about 1.1 billion stars and single colour photometry for an additional 400 million stars, and median radial velocities for about 7 million stars between magnitude 4 and 13. It also contains data for over 14,000 selected Solar System objects. [18] [19]
The coordinates in DR2 use the second Gaia celestial reference frame (Gaia–CRF2), which is based on observations of 492,006 sources believed to be quasars and has been described as "the first full-fledged optical realisation of the ICRS ... built only on extragalactic sources." [20] Comparison of the positions of 2,843 sources common to Gaia–CRF2 and a preliminary version of the ICRF3 shows a global agreement of 20 to 30 μas, although individual sources may differ by several mas. [21] Since the data processing procedure links individual Gaia observations with particular sources on the sky, in some cases the association of observations with sources will be different in the second data release. Consequently, DR2 uses different source identification numbers than DR1. [22] A number of issues have been identified with the DR2 data, including small systematic errors in astrometry and significant contamination of radial velocity values in crowded star fields, which may affect some one percent of the radial velocity values. Ongoing work should resolve these issues in future releases. [23] A guide for researchers using Gaia DR2, which collected "all information, tips and tricks, pitfalls, caveats and recommendations relevant to" DR2, was prepared by the Gaia Helpdesk in December 2019. [17]
Due to uncertainties in the data pipeline, the third data release, based on 34 months of observations, has been split into two parts so that data that was ready first, was released first. The first part, EDR3 (Early Data Release 3), consisting of improved positions, parallaxes and proper motions, was released on 3 December 2020. [24] The coordinates in EDR3 use a new version of the Gaia celestial reference frame (Gaia–CRF3), based on observations of 1,614,173 extragalactic sources, [24] 2,269 of which were common to radio sources in the third revision of the International Celestial Reference Frame (ICRF3). [25] Included is the Gaia Catalogue of Nearby Stars (GCNS), containing 331,312 stars within (nominally) 100 parsecs (330 light-years). [26] [27]
The full DR3, published on 13 June 2022, includes the EDR3 data plus Solar System data; variability information; results for non-single stars, for quasars, and for extended objects; astrophysical parameters; and a special data set, the Gaia Andromeda Photometric Survey (GAPS), providing a photometric time series for about 1 million sources located in a 5.5-degree radius field centered on the Andromeda galaxy. [28] [29] The release dates of EDR3 and DR3 were delayed by the effects of the COVID-19 pandemic on the Gaia Data Processing and Analysis Consortium. [30] [31]
Gaia Focused Product Release from October 2023 focused on Omega Centauri and contained more that half a million stars from that region. [32]
The full data release for the five-year nominal mission, DR4, will include full astrometric, photometric and radial-velocity catalogues, variable-star and non-single-star solutions, source classifications plus multiple astrophysical parameters for stars, unresolved binaries, galaxies and quasars, an exo-planet list and epoch and transit data for all sources. [1] Most measurements in DR4 are expected to be 1.7 times more precise than DR2; proper motions will be 4.5 times more precise. [33]
The last catalogue, DR5, assuming an additional two-year extension of the Gaia mission until late-2024, will consist of full ten years of data. It will be 1.4 times more precise than DR4, while proper motions will be 2.8 times more precise than DR4. [33] It will be published not earlier than three years after the end of the mission.
The Gaia Archive is a catalogue that contains positions and brightnesses for 1.7 billion stars, including distances and proper motions for more than 1.3 billion stars. [34]
An outreach application, Gaia Sky , has been developed to explore the galaxy in three dimensions using Gaia data. [35]
Gaia is a space observatory of the European Space Agency (ESA), launched in 2013 and expected to operate until 2025. The spacecraft is designed for astrometry: measuring the positions, distances and motions of stars with unprecedented precision, and the positions of exoplanets by measuring attributes about the stars they orbit such as their apparent magnitude and color. The mission aims to construct by far the largest and most precise 3D space catalog ever made, totalling approximately 1 billion astronomical objects, mainly stars, but also planets, comets, asteroids and quasars, among others.
21 Aquilae is a solitary variable star in the equatorial constellation of Aquila. It has the variable star designation V1288 Aql; 21 Aquilae is its Flamsteed designation. This object is visible to the naked eye as a dim, blue-white hued star with a baseline apparent visual magnitude of about 5.1. The star is located at a distance of around 680 light-years from Earth, give or take a 20 light-year margin of error. It is moving closer to the Earth with a heliocentric radial velocity of –5 km/s.
9 Aurigae is a star system in Auriga (constellation). It has an apparent magnitude of about 5, making it visible to the naked eye in many suburban skies. Parallax estimates made by the Hipparcos spacecraft put it at about 86 light-years from the solar system, although individual Gaia Data Release 3 parallaxes place all three components at 88 light years.
40 Boötis is a single star located 166.5 light years away from the Sun in the northern constellation of Boötes. It is visible to the naked eye as a dim, yellow-white hued star with an apparent visual magnitude of 5.64. The star is moving away from the Earth with a heliocentric radial velocity of +12 km/s.
N Centauri is a binary star in the southern constellation of Centaurus. The brighter star is dimly visible to the naked eye with an apparent visual magnitude of 5.26, and it is approximately 304 light years away based on parallax. It has an absolute magnitude of +0.76 and is drifting further away from the Sun with a radial velocity of +27 km/s. It is a candidate member of the Sco OB2 moving group.
HD 155035 is the Henry Draper Catalogue designation for a star in the constellation Ara, the Altar. It is located at a distance of approximately 1,450 light-years from Earth and has an apparent visual magnitude of 5.92, making it is faintly visible to the naked eye. This is a red giant star with a stellar classification of M1.5 III. It an irregular variable that changes brightness over an amplitude range of 0.12 magnitudes.
HD 27245, also known as HR 1335 or rarely 25 H. Camelopardalis is a solitary red-hued star located in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 5.4, making it faintly visible to the naked eye. Gaia DR3 Parallax measurements place it approximately 607 light years away from it the Solar System and is drifting further away with a heliocentric radial velocity of 25.2 km/s. At its current distance, HD 27245's brightness is diminished by 0.36 magnitudes due to extinction from interstellar dust. It has an absolute magnitude of −0.27.
74 Cygni is a visual binary star system in the northern constellation Cygnus, located around 249 light years distant from the Sun. It is visible to the naked eye as a faint, white-hued star with a combined apparent visual magnitude of 5.04. The pair orbit each other with a period of 1.57 years and an eccentricity of 0.5. The system is a source of X-ray emission, which is most likely coming from the secondary component.
HD 63399 is an orange hued star located in the southern constellation Puppis, the poop deck. It has an apparent magnitude of 6.45, placing it near the limit for naked eye visibility. Based on parallax measurements from Gaia DR3, the object is estimated to be 445 light years distant. It appears to be receding with a spectroscopic radial velocity of 28.5 km/s. At its current distance, HD 63399 is diminished by 0.29 magnitudes due to interstellar dust.
V915 Scorpii is an orange hypergiant variable star in the constellation Scorpius.
HD 39901 is an orange hued star located in the constellation Columba. It is also called HR 2069, which is the star's Bright Star Catalog designation. Eggen (1989) lists it as a member of the old disk population.
HD 155448 is a quintuple star system consisting of 5 young B-type stars. With an apparent magnitude of 8.72, it is too dim to be visible with the naked eye.
HD 1, also known as HIP 422, is the first star catalogued in the Henry Draper Catalogue. It is located in the northern circumpolar constellation Cepheus and has an apparent magnitude of 7.42, making it readily visible in binoculars, but not to the naked eye. The object is located relatively far away at a distance of 1,220 light years but is approaching the Solar System with a spectroscopic radial velocity of −27.3 km/s.
Chi Octantis, Latinized from χ Octantis, is a solitary star located in the southern circumpolar constellation Octans. It is faintly visible to the naked eye as an orange-hued star with an apparent magnitude of 5.28. The object is located relatively close at a distance of 261 light years based on Gaia EDR3 parallax measurements, but it is receding with a heliocentric radial velocity 33.6 km/s. At its current distance, Chi Octantis' brightness is diminished by 0.24 magnitudes due to interstellar dust. It has an absolute magnitude of +0.81.
12 Trianguli is a solitary star located in the northern constellation Triangulum, with an apparent magnitude of 5.37, making it faintly visible to the naked eye under ideal conditions. The star is situated 160 light years away but is approaching with a heliocentric radial velocity of −24.8 km/s. It is calculated to be about 2.19 Gyr old with a stellar classification of F0 III, making it an F-type giant. It has 1.6 times the mass of the Sun and shines at 14 times the luminosity of the Sun from its photosphere at an effective temperature of 7,199 K.
10 Delphini is a solitary star in the equatorial constellation Delphinus. It has an apparent magnitude of 6.00, allowing it to be faintly seen with the naked eye. Parallax measurements put the object at a distance of 493 light years but is drifting closer with a heliocentric radial velocity of −32 km/s.
15 Delphini is a star in the equatorial constellation Delphinus. It has an apparent magnitude of 5.99, allowing it to be faintly seen with the naked eye. The star is relatively close at a distance of 99 light years but is receding with a heliocentric radial velocity of 4.1 km/s.
HD 194612 is a solitary orange hued star located in the southern circumpolar constellation Octans. It has an apparent magnitude of 5.9, making it visible to the naked eye under ideal conditions. Parallax measurements place it at a distance of 760 light years and it has a low heliocentric radial velocity of 0.3 km/s.
8 Leonis Minoris is a solitary, red hued star located in the northern constellation Leo Minor. It has an apparent magnitude 5.37, making it faintly visible to the naked eye. Based on parallax measurements from the Gaia satellite, the object is estimated to be 492 light years distant. It is receding with a heliocentric radial velocity of 40 km/s. At its current distance, 8 LMi is diminshed by 0.12 magnitudes due to interstellar dust.
HD 198716, also known as HR 7987 or 33 G. Microscopii, is a solitary star located in the southern constellation Microscopium. Eggen (1993) lists it as a member of the Milky Way's old disk population.
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