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The Outer Solar System Origins Survey (OSSOS)

Observations are ongoing for 13B discoveries! Check the Survey Overview for our progress in getting & processing photons.

Overview

Team members should read the Accepted Proposal (access restricted).

OSSOS is a four-year project beginning spring 2013 (first observations were in February 2013), operating on the Megaprime CCD mosaic (1x1 degrees) on the Canada-France-Hawaii Telescope. The discovery and tracking of essentially all the detected targets over two oppositions of observation (actually about 16 months of arc) will occur on this telescope. In both 2013A and 2013B two `blocks' of 21 sq deg will be observed; one near/on the ecliptic and another at some off-ecliptic latitude (the latitude of which will likely be different in the two semesters). Thus, the first year will search 84 sq deg of sky, with an expected depth of m_r = 24.5 to 40% detection efficiency, with 100% of the targets brighter than this limit be tracked (this is based on performance in a 2011B pathfinder program).

The collaboration structure consists of a Core Team and a set of Topic Teams (each of which is led by a Team Leader). The Core Team is in charge of programming observations, reducing the acquired data, detecting objects in a precisely measured way, and providing the various Topic Teams with information on the detected objects and a characterization via a survey simulator (like was done for the CFEPS Survey). For some Topic Team science goals, the data from the core team is all they need to pursue their goals, but for other topic teams additional telescope time at other facilities will be required. (It will be very hard to get CFHT time for such projects in the 2013-2016 period.)

Field Layout

2013A

• OSSOS April 2013 preliminary field layout plot (here for reference. As in the proposal; varied very slightly from the observed location)
• OSSOS 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

2013B

• OSSOS October 2013 field layout plot. The field positions and known TNO locations at October 2013 new moon (4 October).

The project will be surveying two sets of fields, spring and fall. For great detail, see the OSSOSurveyDraft.

In each season a 7x3 block of fields will be positioned near the ecliptic plane and a second group of fields will be positioned off the plane. Each set of fields will be observed repeatedly through-out the semester (a few nights per dark run for 5 dark runs centered on the April/May dark runs for the on/off ecliptic fields). These fields will then be re-observed in 2014A to obtain a high-precision orbits on all KBOs detected in the field. The discovery triplet (near opposition) is the crucial portion, because this is the only place where the magnitude performance will be measured; tracking of objects with detection magnitudes brighter than the 40% efficiency should be >95%.

In addition to deep imaging done to discover and track the TNOs, a heavily-overlapping set of shallower imaging (grey boxes in the layout figure) will allow an extremely precise internal astrometric (and relative photometric) solution in each patch, tied to Sloan. Based on a pathfinder project, this yields orbits of 0.1-1% semimajor axis uncertainty inside the first 5 months, and a factor of 10-30 better by the end of the second year. (RMS residuals are 30-50 milli-arcseconds for bright targets, and 80-100 for fainter ones).

OSSOS will go deeper than previous 4-meter class surveys due to both operations in queue mode and (after mid 2013) the expected IQ improvement provided by CFHT's dome venting (which will lower the median IQ from the current 0.72" to the range 0.6-0.65"). With an expected 40% detection efficiency at r-band magnitude 24.4-24.5, in the ecliptic OSSOS will yield something like 3-4 objects per square degree, with about half that sky density for the off-ecliptic fields.

MPC Release

In September 2013 the Teams will receive the object list for the 2013 as a summary table of internal designations with orbital elements and uncertainties (by this time, the typical object will have a semimajor axis uncertainty of 0.1-1%). Dynamical classification using the SSBN 2008 classification will be provided. Teams will also have the ability to access the full astrometry and the imaging data for each detection should they wish.

MPC codes used in flagging astrometry

Some topic teams will then wish to immediately propose observations to other telescopes for 2014A studies of the 2013A sample; this will likely be the only instant where the topic teams have a proposal advantage over the world. The ephemerides at the time of proposal will be good (in most cases) to +/- 1 arcmin, but if observations occur after March 2014 the 2014A CFHT recovery of all objects will drop uncertainties to a few arcseconds by the time P.I.-led exploitation observations occur.

• September 2013: Teams receiving the discoveries

• Sept-Oct 2013 : Teams propose exploitation observations for 2014A.

• Feb-June 2014: CFHT OSSOS will provide additional astrometry for 2013A discoveries.

• Early 2014: Various telescopes are observing OSSOS targets.

• August 1, 2014: 2013A imaging becomes public to world.

• August 2014: All OSSOS imaging on 2013A targets is now acquired.

MPC submission proposal

 The MPC will get all observations of a given semester 6 months after
 the end of the semesters.  For 2013A, this means an MPC submission
 at the end of January 2014.  This gives observers on quarterly systems a 
  chance to propose for telescope deadlines as late as Feb 1/2014 with
 no competition (basically, one cycle).  It also gives the theory teams
 5 months to work before world sees the MPC release.  A second MPC submission 
 in August 2014 provides the Feb-July 2014 recoveries of the 2013 detections.

Topic Teams

How to join OSSOS

The OSSOS project is divided into topic-teams that are each responsible for ensuring that a particular aspect of the survey science is fully exploited. At the start of the survey each member of the project has elected to participate in one or two topic teams, based on their science interests as stated at the start of the survey. By joining a topic team the science team member is committing to helping the Team in this area of science exploitation. Each team selects one of the team members to be the Team Leader who will act as the principle information conduit back to the survey and is responsible for keeping the topic team focused, organized, and sharing information so that progress is made.

 Team members MUST have a precise well-defined role for what they are committed to do in that Topic Team,
 and agree to openly collaborate with other members of that Topic Team who share similar interests.
 The OSSOS collaborational agreement (to be electronically signed early April 2013 to get access to the data flow) 
 must be accepted by each OSSOS collaborator that wishes access to the target list and OSSOS Survey Simulator 
 before the world release.

OSSOS collaboration, alphabetical listing

Full list of OSSOS collaborators is available.

Core Team

Core

Observation acquisition, moving object detection, orbit linkage, characterization

The OSSOS LP proposal is available on the Core Team's page.

Alphabetical Topic Team list

Binaries

mutual orbits, separation, colours. Leader: A. Parker.

Cometary Activity

Search for coma. Leader: P. Rousselot.

Light curves

Time variable TNOs, phase curves. Leader: S. Benecchi.

Catalogs

Objects slower than OSSOS rate cut) + non-moving object variation (eg. variable stars). Leader: L. Jones.

Nearby objects

Search for and tracking of objects moving faster than OSSOS cuts (roughly, inside 8 AU). SUSPENDED.

Occultations

Predictions, observing campaigns. Leader: W. Fraser.

Resonant Populations

relative populations, libration amplitude distributions. Leader: R. Murray-Clay.

Scattering

Centaurs, Scattering Disk, Oort cloud connection. Leader: N. Kaib

Classical Belt, structure and SDF

H-mag distributions, dependence on class. ABSORBED INTO CORE: Petit as leader.

Surfaces

Colours, NIR spectra. Leader: A. Delsanti.

Thermal Modeling

Thermal evolution of objects. Leader: A. Guilbert

Publications and Proposals

Survey and Team logos for use in presentations etc (high-res PNGs). The font is (free!) Sofia Pro Light. Download it here.

Publications and Proposals should be entered on this link.

Principle Contacts

At the current time, the principle contact for each team member should be their Topic Team's Team Leader. Team Leader's can contact any of the three core-team members:

Brett Gladman

JJ Kavelaars

Jean-Marc Petit

Timeline and Upcoming Deadlines

• June 6/2012: OSSOS was number 1 ranked CFHT Large program. 560hr awarded.

• Feb. 2013 - Aug 2013 : 2013A data acquisition.
• Aug 2013 - late Jan 2014 : 2013B data acquisition.

• Oct 6/2013: Second OSSOS team meeting, at 2013 DPS meeting in Denver.

Help

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