Exo-MerCat: The Exoplanet Merged Catalog

Exo-MerCat: The Exoplanet Merged Catalog#

Exo-MerCat is a Python software designed to generate a catalog of known and candidate exoplanets, where data is merged from various exoplanet catalogs.

Exo-MerCat retrieves a common name for the planet target, linking its host star name with the preferred identifier in the most well-known stellar databases. This makes the merging of different input sources possible and it has allowed the release of a standardized catalog containing data from the major input catalogs used in the community: the Exoplanets Encyclopaedia[1], the NASA Exoplanet Archive[2], the Open Exoplanet Catalogue[3], the TESS Objects of Interest Catalog[4] and the EPIC/K2 Objects of Interest Catalog[5].

Warning

Because of the nature of the merge, this catalog is not self-consistent (i.e., all measurements for the same target don’t belong to the same reference paper). Rather, it is a collection of the most precise estimates for each planetary parameter (mass, minimum mass, radius, period, semi-major axis, eccentricity, inclination), based on the lowest relative error, and the corresponding reference for each preferred estimate.

Exo-MerCat assigns a main identifier from SIMBAD or TESS Input Catalog v8.2, performing name- and coordinate-based queries. The information on each target collected from any of the original input sources is then collapsed to form a single Exo-MerCat entry.

The catalog is available via TAP (see Get Exo-MerCat from TAP for more info). The user can also download the source file from the GitHub and run Exo-MerCat locally (see Run Exo-MerCat locally).

Note

If you use Exo-MerCat, please cite the following papers: Alei et al. 2020, Alei et al. 2025

Changelog#

v2.1.0#

  • Hotfix to accomodate on changes on NASA Exoplanet Archive. The NASA and EPIC tables now have two different columns, gaia_dr2_id and gaia_dr3_id, instead of the earlier version which only had gaia_id displaying Gaia DR2 identifiers. Both Gaia DR2 and Gaia DR3 identifiers are now included in Exo-MerCat’s aliases when available. Edited nasa.py and epic.py and related unit tests.

  • New minor feature: Improved check_binary_mismatch after encountering instance where coordinates were above the default tolerance. Added related warning in logs. Refactored test__check_binary_mismatch accordingly.

v2.0.1#

  • Bugfix on main_id_alias column.

v2.0.0 (see Alei et al. 2025)#

  • Added TESS Project Candidates Table as input source; promoted EPIC/K2 Planets and Candidates Table to input source; removed Exoplanet Orbit Database (now retired); updated interfaces with NASA Exoplanet Archive, Kepler Objects of Interest catalog, and Exoplanet Encyclopaedia.

  • Increased number of entries and improved completeness of parameter estimates in Exo-MerCat catalog.

  • Main identifier now searched in SIMBAD and TESS Input Catalog v8.2 for both name- and coordinate-based queries; coordinate-based queries now use a smaller tolerance radius (1 arcsec instead of 36 arcsec), reducing errors.

  • Grouping of entries now considers estimates of period or semi-major axis, ensuring more accurate merging and resolving discrepancies in planet letters.

  • Exo-MerCat now produces a filtered catalog excluding brown dwarf candidates with mass smaller than 20 MJup, along with additional flags for custom filtering.

  • Script generates more user-friendly log files, allowing users to handle corrections through ancillary files, adding flexibility.

  • Code restructured into modules and functions, facilitating future input source integration.

  • Exo-MerCat released as open-source, fully tested, and documented.

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