Solar System Objects in Gaia DR2

 

Figure 1a: Plot of the orbits of the asteroids in Gaia Data Release 2. Left image is coloured according to perihelion distance (the distance of the asteroid in its orbit where it is closest to the Sun). Right image is coloured following the albedo of the asteroids. ESA/Gaia/DPAC, P. Tanga

Figure 1b: Zooms of the plot of the orbits as shown in Figure 1a. Left image is coloured according to perihelion distance. Right image is coloured following the albedo of the asteroids. ESA/Gaia/DPAC, P. Tanga

 

By the dawn of the 19th century, our Solar System was still a relatively unpopulated place, containing only a small bunch of big celestial bodies: the planets. But on that January 1st, 1801, this picture started to change thanks to the discovery, by the priest astronomer Giuseppe Piazzi, of a “minor planet”. He named it as “Ceres”, after the Roman goddess of grain and fertility.

As we know today Ceres is just the largest member (975 km in diameter) of a large population of asteroids, reaching more than 750.000 objects and still growing fast, as smaller and smaller objects are observed. The development of modern telescopes and detectors has strongly enhanced the pace of discoveries over the last year. To have an example of that, it is sufficient to look at the second Data Release of Gaia, in which the observations of 14.099 asteroids are published, collected in less than 2 years. But, it took nearly two centuries after Piazzi’s finding (i.e. till the mid-1990s), to discover as many asteroids from the ground!

The published Gaia data set in data release 2 only contains a selected sample of asteroids, as the observations of many more have already been collected, and will become available in future releases. By the end of the mission there will most probably be more than 300.000, and the accurate positions, 100s times better than in the past, will disclosing new possibility of investigation.

The pictures above (Figure 1a and b) show a colorful plot of the orbits of the asteroids in Gaia’s second data release, between the Sun and Jupiter. As usual in scaled plots, the Solar System appears crowded and individual lines merge in the region of the Main Belt, between Mars and Jupiter, where most asteroids concentrate. In reality, of course, these asteroid trajectories are millions of km apart.

In the plot at the left, orbits are colored according to the perihelion distance, in other words their minimum distance from the Sun. Blue trajectories are rather eccentric and belong to Near Earth Asteroids. The green population is the Main Belt. Farther away from the Sun, the gravitational perturbations induced by Jupiter prevent to have a stable population, with the exception of the Trojan asteroids (in red) that precede and follow the planet on its orbit in safe regions of stability.

In the plot to the right, asteroid orbits are colored following their albedo, i.e. the “lightness” of the surface of an asteroid. The fingerprint of a gradient of composition appears, with dark asteroids (in red) dominating the external regions, while lightest bodies are in the inner main belt. This pattern is probably inherited from the formation of the Solar System, however on the top of it a certain degree of mixing appears. The short-lived Near Earth Asteroids sample populations of different albedos.

The data on albedos are produced from the Wide Infrared Space Explorer (WISE) of NASA, but in future data releases Gaia will also provide asteroid spectra and permit a complete characterization of the asteroid belt. The combination of dynamical and physical data by Gaia, plus other surveys, is offering an unprecedented opportunity to better understand the origin and the evolution of the Solar System.

Figure 2. For this plot, all the observations of an asteroid, from both ground-based telescopes and Gaia, are used to determine its precise orbit. The figure represents the spread around the position of the asteroid, derived from this orbital model, for the archive data (in blue) and for Gaia (in red). All Gaia data points are scattered in a tiny circle, about 300 times smaller than the previous data. This difference illustrates well the typical, dramatic increase in accuracy brought by DR2. Credits: ESA/Gaia/DPAC, F. Spoto

 

For the Data Release 2 of Gaia, the main focus is on astrometry. Figure 2 and 3 illustrate the accuracy of the measurement of asteroids and the breakthrough that they represent. An orbit has been adjusted to all Gaia measurements of all asteroids present in Data Release 2. An example of the results is shown in Figure 2. Figure 3 represents the residuals (the difference between the observation and the position provided by the orbit) for each observation. On average, the residuals increase with magnitude: fainter objects are more difficult to measure and give larger errors. However, one can notice that the measurements are always more precise than 10 mas, and the residuals fall below 1 mas in the range of magnitude below G~18.

It is the first time that such a massive amount of sub-miliarcsecond measurements is available. Many applications will strongly benefit from them, such as the search of the signature of subtle non-gravitational perturbations modifying asteroid orbits, or the prediction of stellar occultations (when an asteroid briefly passes in front of a star). Through these approaches, Gaia is going to impact at a large extent our understanding of the small body population and of their physical properties.

Figure 3. Average residuals of the orbital fit to the asteroid observations published in DR2. Each point represents a different transit on the Gaia focal plane, and the residuals are measured in the direction of the Gaia scan (AL, along scan). Colors are related to the density of points, and the black line is the average value. For DR2, effects due to the asteroid size and motion are not yet taken into account in the data processing and require more efforts to be corrected. Improvements can be expected in future releases. Credits: ESA/Gaia/DPAC, P. Tanga, F. Spoto

 

 

Credits: ESA/Gaia/DPAC, P. Tanga, F. Spoto, the entire CU4 team, and co-authors of the paper "Gaia Data Release 2: Observations of Solar System objects"

Additional credits: The Wide-field Infrared Survey Explorer is a joint project of the University of California, Jet Propulsion Laboratory/California Institute of Technology, funded by NASA.

Published 25 April 2018

 

 

Gaia Sky video: Tour through the Gaia DR2 asteroids

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A Guide for Scientists - Gaia DR2 Solar System Objects

 

Selected asteroids detected by Gaia between August 2014 and May 2016

Image of the Week Archive

2024

02/04: The Gaia Cataclysmic Variable hook

2023

19/12: 10 Science topics to celebrate Gaia's 10 years in space

31/10: Gaia observes cosmic clock inside a heavenly jewel

10/10: Gaia Focused Product Release stories

27/09: Does the Milky Way contain less dark matter than previously thought?

22/09: Mass-luminosity relation from Gaia's binary stars

13/09: Gaia DPAC CU8 seminars

13/06: Gaia's multi-dimensional Milky Way

18/05: Mapping the Milky Way

15/05: Goonhilly station steps in to save Gaia science data

25/04: The Gaia ESA Archive

05/04: Dual quasar found to be hosted by an ongoing galaxy merger at redshift 2.17

21/03: GaiaVari: a citizen science project to help Gaia variability classificaton

09/02: Missing mass in Albireo Ac: massive star or black hole?

31/01: Gaia reaches to the clouds – 3D kinematics of the LMC

25/01: Meet your neighbours: CNS5 - the fifth catalogue of nearby stars

18/01: A single-object visualisation tool for Gaia objects

2022

25/11: 100 months of Gaia data

23/11: The astonishment

09/11: Gamma-Ray Burst detection from Lagrange 2 point by Gaia

04/11: Gaia's first black hole discovery: Gaia BH1

26/10: Are Newton and Einstein in error after all?

21/10: Gaia ESA Archive goes live with third data release

06/10: Mapping the interstellar medium using the Gaia RVS spectra

26/09: Gaia on the hunt for dual quasars and gravitational lenses

23/09: Gaia's observation of relativistic deflection of light close to Jupiter

13/06: Gaia Data Release 3

10/06: MK classification of stars from BP/RP spectrophotometry across the Hertzsprung-Russell diagram

09/06: BP/RP low-resolution spectroscopy across the Hertzsprung-Russell diagram

27/05: Cepheids and their radial velocity curves

23/05: The Galaxy in your preferred colours

19/05: GaiaXPy 1.0.0 released, a tool for Gaia's BP/RP spectra users

11/05: Systemic proper motions of 73 galaxies in the Local group

28/03: Gaia query statistics

16/03: Gaia's first photo shooting of the James Webb Space Telescope

08/03: Gaia's women in science - coordination unit 8

25/02: Not only distances: what Gaia DR3 RR Lyrae stars will tell us about our Galaxy and beyond

11/02: Gaia's women in science

31/01: Astrometric orbit of the exoplanet-host star HD81040

12/01: The Local Bubble - source of our nearby stars

05/01: A Milky-Way relic of the formation of the Universe

2021

23/12: Signal-to-Noise ratio for Gaia DR3 BP/RP mean spectra

22/12: The 7 October 2021 stellar occultation by the Neptunian system

01/12: Observation of a long-predicted new type of binary star

24/09: Astrometric microlensing effect in the Gaia16aye event

22/09: the power of the third dimension - the discovery of a gigantic cavity in space

16/09: An alternative Gaia sky chart

25/08: Gaia Photometric Science Alerts and Gravitational Wave Triggers

09/07: How Gaia unveils what stars are made of

23/06: Interviews with CU3

27/04: HIP 70674 Orbital solution resulting from Gaia DR3 processing

30/03: First transiting exoplanet by Gaia

26/03: Apophis' Yarkovsky acceleration improved through stellar occultation

26/02: Matching observations to sources for Gaia DR4

2020

22/12: QSO emission lines in low-resolution BP/RP spectra

03/12: Gaia Early Data Release 3

29/10: Gaia EDR3 passbands

15/10: Star clusters are only the tip of the iceberg

04/09: Discovery of a year long superoutburst in a white dwarf binary

12/08: First calibrated XP spectra

22/07: Gaia and the size of the Solar System

16/07: Testing CDM and geometry-driven Milky Way rotation Curve Models

30/06: Gaia's impact on Solar system science

14/05: Machine-learning techniques reveal hundreds of open clusters in Gaia data

20/03: The chemical trace of Galactic stellar populations as seen by Gaia

09/01: Discovery of a new star cluster: Price-Whelan1

08/01: Largest ever seen gaseous structure in our Galaxy

2019
20/12: The lost stars of the Hyades
06/12: Do we see a dark-matter like effect in globular clusters?
12/11: Hypervelocity star ejected from a supermassive black hole
17/09: Instrument Development Award
08/08: 30th anniversary of Hipparcos
17/07: Whitehead Eclipse Avoidance Manoeuvre
28/06: Following up on Gaia Solar System Objects
19/06: News from the Gaia Archive
29/05: Spectroscopic variability of emission lines stars with Gaia
24/05: Evidence of new magnetic transitions in late-type stars
03/05: Atmospheric dynamics of AGB stars revealed by Gaia
25/04: Geographic contributions to DPAC
22/04: omega Centauri's lost stars
18/04: 53rd ESLAB symposium "the Gaia universe"
18/02: A river of stars
2018
21/12: Sonification of Gaia data
18/12: Gaia captures a rare FU Ori outburst
12/12: Changes in the DPAC Executive
26/11:New Very Low Mass dwarfs in Gaia data
19/11: Hypervelocity White Dwarfs in Gaia data
15/11: Hunting evolved carbon stars with Gaia RP spectra
13/11: Gaia catches the movement of the tiny galaxies surrounding the Milky Way
06/11: Secrets of the "wild duck" cluster revealed
12/10: 25 years since the initial GAIA proposal
09/10: 3rd Gaia DPAC Consortium Meeting
30/09: A new panoramic sky map of the Milky Way's Stellar Streams
25/09: Plausible home stars for interstellar object 'Oumuamua
11/09: Impressions from the IAU General Assembly
30/06: Asteroids in Gaia Data
14/06: Mapping and visualising Gaia DR2

25/04: In-depth stories on Gaia DR2

14/04: Gaia tops one trillion observations
16/03: Gaia DR2 Passbands
27/02: Triton observation campaign
11/02: Gaia Women In Science
29/01: Following-up on Gaia
2017
19/12: 4th launch anniversary
24/11: Gaia-GOSA service
27/10: German Gaia stamp in the making
19/10: Hertzsprung-russell diagram using Gaia DR1
05/10: Updated prediction to the Triton occultation campaign
04/10: 1:1 Gaia model arrives at ESAC
31/08: Close stellar encounters from the first Gaia data release
16/08: Preliminary view of the Gaia sky in colour
07/07: Chariklo stellar occultation follow-up
24/04: Gaia reveals the composition of asteroids
20/04: Extra-galactic observations with Gaia
10/04: How faint are the faintest Gaia stars?
24/03: Pulsating stars to study Galactic structures
09/02: Known exoplanetary transits in Gaia data
31/01: Successful second DPAC Consortium Meeting
2016
23/12: Interactive and statistical visualisation of Gaia DR1 with vaex
16/12: Standard uncertainties for the photometric data (in GDR1)
25/11: Signature of the rotation of the galactic bar uncovered
15/11: Successful first DR1 Workshop
27/10: Microlensing Follow-Up
21/10: Asteroid Occultation
16/09: First DR1 results
14/09: Pluto Stellar Occultation
15/06: Happy Birthday, DPAC!
10/06: 1000th run of the Initial Data Treatment system
04/05: Complementing Gaia observations of the densest sky regions
22/04: A window to Gaia - the focal plane
05/04: Hipparcos interactive data access tool
24/03: Gaia spots a sunspot
29/02: Gaia sees exploding stars next door
11/02: A new heart for the Gaia Object Generator
04/02: Searching for solar siblings with Gaia
28/01: Globular cluster colour-magnitude diagrams
21/01: Gaia resolving power estimated with Pluto and Charon
12/01: 100th First-Look Weekly Report
06/01: Gaia intersects a Perseid meteoroid
2015
18/12: Tales of two clusters retold by Gaia
11/11: Lunar transit temperature plots
06/11: Gaia's sensors scan a lunar transit
03/11: Celebrity comet spotted among Gaia's stars
09/10: The SB2 stars as seen by Gaia's RVS
02/10: The colour of Gaia's eyes
24/09: Estimating distances from parallaxes
18/09: Gaia orbit reconstruction
31/07: Asteroids all around
17/07: Gaia satellite and amateur astronomers spot one in a billion star
03/07: Counting stars with Gaia
01/07: Avionics Model test bench arrives at ESOC
28/05: Short period/faint magnitude Cepheids in the Large Magellanic Cloud
19/05: Visualising Gaia Photometric Science Alerts
09/04: Gaia honours Einstein by observing his cross
02/04: 1 April - First Look Scientists play practical joke
05/03: RR Lyrae stars in the Large Magellanic Cloud as seen by Gaia
26/02: First Gaia BP/RP deblended spectra
19/02: 13 months of GBOT Gaia observations
12/02: Added Value Interface Portal for Gaia
04/02: Gaia's potential for the discovery of circumbinary planets
26/01: DIBs in three hot stars as seen by Gaia's RVS
15/01: The Tycho-Gaia Astrometric Solution
06/01: Close encounters of the stellar kind
2014
12/12: Gaia detects microlensing event
05/12: Cat's Eye Nebula as seen by Gaia
01/12: BFOSC observation of Gaia at L2
24/11: Gaia spectra of six stars
13/11: Omega Centauri as seen by Gaia
02/10: RVS Data Processing
12/09: Gaia discovers first supernova
04/08: Gaia flag arrives at ESAC
29/07: Gaia handover
15/07: Eclipsing binaries
03/07: Asteroids at the "photo finish"
19/06: Calibration image III - Messier 51
05/06: First Gaia BP/RP and RVS spectra
02/06: Sky coverage of Gaia during commissioning
03/04: Gaia source detection
21/02: Sky-background false detections in the sky mapper
14/02: Gaia calibration images II
06/02: Gaia calibration image I
28/01: Gaia telescope light path
17/01: First star shines for Gaia
14/01: Radiation Campaign #4
06/01: Asteroid detection by Gaia
2013
17/12: Gaia in the gantry
12/12: The sky in G magnitude
05/12: Pre-launch release of spectrophotometric standard stars
28/11: From one to one billion pixels
21/11: The Hipparcos all-sky map
15/10: Gaia Sunshield Deployment Test
08/10: Initial Gaia Source List
17/09: CU1 Operations Workshop
11/09: Apsis
26/08: Gaia arrival in French Guiana
20/08: Gaia cartoons
11/07: Model Soyuz Fregat video
01/07: Acoustic Testing
21/06: SOVT
03/06: CU4 meeting #15
04/04: DPCC (CNES) 
26/03: Gaia artist impression 
11/02: Gaia payload testing  
04/01: Space flyby with Gaia-like data
2012
10/12: DPAC OR#2. Testing with Planck
05/11: Galaxy detection with Gaia
09/10: Plot of part of the GUMS-10 catalogue
23/07: "Gaia" meets at Gaia
29/06: The Sky as seen by Gaia
31/05: Panorama of BAM clean room
29/03: GREAT school results
12/03: Scanning-law movie
21/02: Astrometric microlensing and Gaia
03/02: BAM with PMTS
12/01: FPA with all the CCDs and WFSs
2011
14/12: Deployable sunshield
10/11: Earth Trojan search
21/10: First Soyuz liftoff from the French Guiana
20/09: Fast 2D image reconstruction algorithm
05/09: RVS OMA
10/08: 3D distribution of the Gaia catalogue
13/07: Dynamical Attitude Model
22/06: Gaia's view of open clusters
27/05: Accuracy of the stellar transverse velocity
13/05: Vibration test of BAM mirrors
18/04: L. Lindegren, Dr. Honoris Causa of the Observatory of Paris
19/01: Detectability of stars close to Jupiter
05/01: Delivery of the WFS flight models
2010
21/12: The 100th member of CU3
17/11: Nano-JASMINE and AGIS
27/10: Eclipsing binary light curves fitted with DPAC code
13/10: Gaia broad band photometry
28/09: Measuring stellar parameters and interstellar extinction
14/09: M1 mirror
27/08: Quest for the Sun's siblings
 
Please note: Entries from the period 2003-2010 are available in this PDF document.