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OSSOS observing ended in 2017.

Survey observations were acquired between 2013 and 2017 by the Canada France Hawaii Telescope and are processed and distributed using the Canadian Advanced Network For Astronomical Research. For additional public information is available from our public web site

Refereed Journal Articles

  1. II. A Sharp Transition in the Absolute Magnitude Distribution of the Kuiper Belt’s Scattering Population (2016) Shankman et al.
  2. III—Resonant Trans-Neptunian Populations: Constraints from the first quarter of the Outer Solar System Origins Survey (2016) Volk et al.
  3. Outer Solar System Origins Survey. I. Design and First-quarter Discoveries (2016) Bannister et al.
  4. IV. Discovery of a Dwarf Planet Candidate in the 9:2 Resonance with Neptune (2016) Bannister et al.
  5. V. Diffusion in the Orbit of a High-perihelion Distant Solar System Object (2017) Bannister et al.
  6. VI. Striking Biases in the Detection of Large Semimajor Axis Trans-Neptunian Objects (2017) Shankman et al.
  7. VIII. The Transition between Two Size Distribution Slopes in the Scattering Disk (2018) Lawler et al.
  8. VII. 800+ Trans-Neptunian Objects—The Complete Data Release (2018) Bannister et al.
  9. X. How to use a Survey Simulator: Statistical Testing of Dynamical Models Against the Real Kuiper Belt (2018) Lawler et al.
  10. IX. Two Objects in Neptune's 9:1 Resonance—Implications for Resonance Sticking in the Scattering Population (2018) Volk et al.
  11. XI. No active centaurs in the Outer Solar System Origins Survey (2019) Cabral et al.
  12. XIII. Fossilized Resonant Dropouts Tentatively Confirm Neptune’s Migration Was Grainy and Slow (2019) Lawler et al.
  13. XV. Probing the Distant Solar System with Observed Scattering TNOs (2019) Kaib et al.
  14. XIV. The Plane of the Kuiper Belt (2019) Van Laerhoven et al.
  15. XIX. Testing Early Solar System Dynamical Models Using OSSOS Centaur Detections (2019) Nesvorný et al.
  16. XII. Variability Studies of 65 Trans-Neptunian Objects Using the Hyper Suprime-Cam (2019) Alexandersen et al.
  17. XVIII. Constraining Migration Models with the 2:1 Resonance Using the Outer Solar System Origins Survey (2019) Chen et al.
  18. dearth of small members in the Haumea family revealed by OSSOS (2020) Pike et al.
  19. XX: The Meaning of Kuiper Belt Colors (2020) Nesvorný et al.
  20. XVII. An upper limit on the number of distant planetary objects in the Solar System (2021) Ashton et al.
  21. XXI. Collision Probabilities in the Edgeworth-Kuiper Belt (2021) Abedin et al.
  22. The eccentricity and inclination distributions of the stable Neptunian Trojans (2021) Lin et al.
  23. Finds an Exponential Cutoff in the Size Distribution of the Cold Classical Kuiper Belt (2021) Kavelaars et al.
  24. XXIII. 2013 VZ70 and the Temporary Coorbitals of the Giant Planets (2021) Alexandersen et al.
  25. XXV: Large Populations and Scattering-Sticking in the Distant Trans-Neptunian Resonances (2022) Crompvoets et al.
  26. XXVI. On the Lack of Catastrophic Collisions in the Present Kuiper Belt (2022) Abedin et al.
  27. Hot Main Kuiper Belt Size Distribution from OSSOS (2023) Petit et al.
  28. XXVII. Population Estimates for Theoretically Stable Centaurs between Uranus and Neptune (2023) Dorsey et al.

Data Releases


The Teams will receive the object list for each semester's discoveries as a summary table of internal designations with orbital elements and uncertainties. At release, a typical object will have a semimajor axis uncertainty of 0.1-1%. Dynamical classification using the SSBN 2008 classification will be provided. Core will also provide access to the full astrometry and the imaging data for each detection.

Some topic teams will then wish to propose observations to other telescopes for next-semester studies of the sample; this will likely be the only time when the topic teams have a proposal advantage over the world. At the time of proposal, the ephemerides of most objects will be good to +/- < 30"; the half-year-later CFHT recovery of all objects will have dropped these uncertainties to a few arcseconds by the time P.I.-led exploitation observations occur.


We aim to submit all observations of a given semester to the MPC 6 months after the end of the semester, except for the first semester (2013), which was delayed longer. This gives observers on quarterly systems a chance to propose for telescope deadlines a cycle later with no competition. It also gives the theory teams 5 months to work before the world sees the MPC release. Recovery observations will be sent as a batch to the MPC with the same time delay.

CFHT imaging becomes public a year after the end of each semester, e.g. on August 1, 2016, the 2015A CFHT imaging becomes public to the world.

Collaboration Teams

The principle contact for each team member should be their topic team's leader.

Team leaders can contact the Core.

Full list of OSSOS collaborators
CFHT image acquisition, moving object detection, orbit linkage, characterisation. (Teleconference minutes)
- Classical Belt, structure and SDF
H-mag distributions, dependence on class. ABSORBED INTO CORE: Petit as leader.
Objects slower than OSSOS rate cut) + non-moving object variation (eg. variable stars). Leader: L. Jones.
mutual orbits, separation, colours. Leader: K. Noll.
Cometary Activity
Search for coma. Leader: P. Rousselot.
Light curves
Time variable TNOs, phase curves. Leader: M. Schwamb.
Predictions, observing campaigns. Leader: W. Fraser.
Resonant Populations
relative populations, libration amplitude distributions. Leader: R. Murray-Clay
Centaurs, Scattering Disk, Oort cloud connection. Leader: N. Kaib
Colours, NIR spectra. Leader: A. Delsanti.


Nearby objects
Search for and tracking of objects moving faster than OSSOS cuts (roughly, inside 8 AU). SUSPENDED.
Thermal Modeling
Thermal evolution of objects. Leader: A. Guilbert ALL FUNCTIONS MERGED INTO SURFACES
Jovian Trojans
Proposed Leader: F. Yoshida. Work tasks and worker list never finalized. Does not yet formally exists.

How to join OSSOS

See the main OSSOS web site:

Publications and Proposals


Observations have concluded.

Original proposals: see the survey draft and the Accepted Proposal (access restricted to collaboration only).

Figures for presentations etc.


  • April 2013 preliminary field layout plot (here for reference. As in the proposal; varied very slightly from the observed location)
  • April 2013 observed plot - as the O and E fields have oppositions a month apart, the E field is shown at its 9 April moon-dark location, and the O field at its 8 May moon-dark location. The known TNOs plotted are for new moon, May 9.
  • 13AE discoveries plot - all positions for 9 April 2013




  • June 6/2012: OSSOS was number 1 ranked CFHT Large program. 560hr awarded.
  • Jan 2013: OSSOS began observation.
  • Oct 6/2013: Second OSSOS team meeting, at 2013 DPS meeting in Denver.
  • June 25-27 2014: OSSOS team workshop in Beaune, France. Meeting Website
  • Nov 2014: Third OSSOS team meeting, 2014 DPS in Tucson.
  • Nov 2015: Fourth OSSOS team meeting, 2015 DPS in Washington DC.
  • Oct 2016: Fifth OSSOS team meeting just before 2016 DPS/EPSC in Pasedena
  • Jan 31/2017: End of 4-year CFHT OSSOS LP allocation
  • July 2017: Sixth OSSOS team meeting in Belfast, UK.
  • Dec 2017: OSSOS concluded observation.


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