Identifications

The Minor Planet Center (MPC) uses the term "identification" to refer to the situations when:

  • Two or more tracklets are discovered to be the same underlying object and hence a new designation is created. We refer to this kind of link as ITF-to-ITF.
  • A tracklet is discovered to be the same underlying object as an existing designated object or of a NEOCP object. We refer to this kind of link as ITF-to-DES or ITF-to-NEOCP.
  • Two or more designated orbits are discovered to be the same underlying object and hence an identification is made between their designations. We refer to this kind of link as DES-to-DES.
  • Two or more objects on the NEOCP are linked together. We refer to this kind of link as NEOCP-to-NEOCP.

The Identifications Pipeline

  • The pipeline attempts to automatically process any object type submitted.
    • NEO and MBA linkages are processed automatically.
    • ITF tracklets can be added to an NEOCP candidate.
    • Two NEOCP candidates can be linked to one another while on the NEOCP.
    • NEOCP candidates can be linked to a known object (and will subsequently be removed from the NEOCP).
    • NEOCP candidates can be labeled as artificial, as long as sat_id identifies them as well. The same applies to ITF tracklets.
    • The automated processing will fail for parabolic and hyperbolic orbits.
    • The automated processing will likely fail for distant objects (such as TNOs) and Natural Satellites.
    • Comets are not processed automatically.
    • If an NEOCP candidate is matched with a known one-opposition NEO and new astrometry extends the arc to multiple-opposition, a recovery MPEC is issued if new astrometry provides two distinct nights: two nights are defined when the arc length of the NEOCP object covers more than 0.75 days (or covers more than 0.5 day when the astrometry if from at least three distinct obscodes).
    • Single tracklets or shorter arcs extending NEO or TNO from one-opposition to multi-oppositions are moved to the recovery page.
    • Identifications of numbered objects with unnumbered objects are processed immediately by the pipeline, but only published during MPCs.
  • If a linkage is approved for a Comet, Natural Satellite, or a TNO which requires an MPEC, the object is sent to a manual queue for publication.
  • We strongly discourage the submission of links that only provide single tracklet on a new apparition - that could be a false positive. At least two tracklets on the same apparition usually proves the link is correct.

Processing Timelines and Status

  • The current status of the identification pipeline can be viewed here.
  • The identification pipeline runs every 5 minutes, fetching unprocessed submissions, prioritizing NEOCP submissions. We suggest submitting smaller batches (<= 100 identifications) and waiting until the batches are processed before submitting new ones.
  • Designation-to-Designation linking (DES-DES) is suspended while MPC publications are being prepared. Submitted linkages will be processed after the MPCs are published.
  • The identifications pipeline is paused while the DAILY ORBIT UPDATE (DOU) is being prepared (12:00 UTC), the pause takes usually 20-60 minutes.
  • The MPC reviews every week all the submissions that have failed in the pipeline. As a result, additional linkages may be manually accepted. Please note that the fraction of failed identifications is very small, usually between 1% and 2%.
  • Comets, Natural Satellites, and (most) TNOs are manually processed. This may take a few weeks. If your linkage is time critical in some way, please submit a Jira ticket.
  • If you have any doubts about the status of your submission, please contact us using the Jira Helpdesk.

Submitting Identifications

Please note the submission form does not currently support:

  • The deletion of identifications.
  • Designations that need to be retired.
  • Identifications where some tracklets need to be redesignated before the identification can be processed.

Failed submissions

If you'd like to receive an automated message when your submitted linkaged failed in the ID pipeline, please add the following text in the comment section: REPLY_EMAIL and don't forget to submit your email address as well in the submission header.
Potential reasons for failures:

  • The User has submitted the observations of a single night that extends one apparition to two oppositions. This is not allowed.
  • Short arc issue: minimum conditions not met (See the criteria.)
  • The User has requested to link two one apparitions TNOs. This is not allowed.
  • The User has submitted an arc extension for a one apparition TNO. At present, this is not automated and it won't be handled by the pipeline.
  • Near duplicates present - detection(s) of submitted ITF tracklet as part of a submitted linkage is very close (spacially - 2 arc seconds, temporaly - 2 seconds) to another ITF or published detection(s).
  • The orbit fit failed.
  • The following designation is not allowed <DESIGNATION> - e.g. designations starting with K15B and K14W cannot be currently created until the Extended Packed Provisional Designation Scheme is not implemented.
  • NEW NEO Identified from ITF to ITF: MPEC Needed (MPEC for NEO is issued manually)
  • Not enough nights in a multi-apparition ITFITF orbit (See the criteria.)
  • ITF to ITF object is too large - New ITFITF objects that are unusually large (measured by the absolute magnitude H) are left for manual processing: NEOs H<17, Mars-Crossers H<16.5, inner and central MB H<16, outer MB H<15.5, Hildas and Trojans H<14).
  • Designation does not exist

Double Designations

A subset of identifications is made between objects designated within the same opposition. Historically, the MPC referred to these as "double designations". An example involves the double designation/identification made between 2017 SL83 and 2017 UH33.

As of June 1, 2020, the MPC will cease to use the "double designation" terminology and will simply refer to them as identifications.

Summary of Linkages


Every year, the MPC creates a summary report of all the identifications that have been submitted, accepted by our pipeline and then published.

2021 Summary
2022 Summary
2023 Summary
2024 Summary


The Isolated Tracklet File (ITF)

The Isolated Tracklet File (ITF) containing Isolated Tracklets can be downloaded from here. Please ensure you have read this document.

The Minor Planet Center is hosted by the Center for Astrophysics | Harvard & Smithsonian.
The Minor Planet Center is funded by NASA.