The MEarth Project


MEarth Photometric Data Release

The MEarth team is pleased to release to the community all our M dwarf light curves taken during the first ten official years of the survey. We have used these light curves to search for transiting planets, eclipsing binaries, and photometric rotation periods, but maybe you can find something we missed!

Note on MEarth light curves of TOIs

These data releases do not include MEarth follow-up light curves of TESS objects of interest (TOIs). Instead, these are uploaded immediately to ExoFOP-TESS and can be found there. The same file format is used but we provide a choice of photometric apertures not provided in the standard releases to aid in analysis of blends. All postings to ExoFOP-TESS are under tfopwg permissions as part of subgroup 1 (SG1) of the TESS follow-up observing program (TFOP) and are accessible to TFOP members immediately and the public after 1 year.

Release Schedule

Each year of MEarth-North observations is punctuated by a summer monsoon season in Arizona. Shut-down and start-up dates vary from year-to-year, but no observations are ever gathered during the month of August, when the observatory is officially closed. The data released here comprise observations gathered starting after the end of the 2008 monsoon and leading up until the start of the 2018 monsoon. In the years to come, we plan to release new light curves one year after the monsoon following the year in which they were taken. For consistency, we have adopted the same schedule for MEarth-South, even though it is possible to gather data there year-round.

This page contains MEarth's Data Release 8 (DR8), which was posted 1 September 2019. It has been superseded by a more up-to-date data release. Click here for the most recent MEarth Data Release!.

Before you Begin

Please read the release notes! We strongly encourage anyone interested in using MEarth light curves to do so. In addition to descriptions of the format and organization of the light curve files, they contain important information regarding the properties and limitations of the data. Additionally, see Irwin et al. (2011) and Newton et al. (2016) for a general discussion of measuring rotation periods in MEarth light curves and Berta et al. (2012) for issues pertaining to transit-finding in MEarth data. For interested readers, we also include a description of the data processing pipeline.

Light Curves

The light curves are presented in four batches, grouped by hemisphere, season and by which filter was used to gather the observations (see release notes). For ease of reading, light curves are presented as plain text ASCII files. On the following four pages, you will have the option either to download light curves (and finder charts) for individual stars of interest or to download the entire sample of light curves as a gzipped tar file:

2008-2010 MEarth-North Target Light Curves (broad RG715 filter)
2010-2011 MEarth-North Target Light Curves (interference filter)
2011-2018 MEarth-North Target Light Curves (broad RG715 filter)
2014-2018 MEarth-South Target Light Curves (broad RG715 filter)

The files available for download should be thought of as working copies of the MEarth light curves. As we identify improvements that can be made to the data reduction, we may reprocess the data and post the updates here, in addition to our regularly scheduled yearly releases. Archives of all previous releases will remain available through this site. No additional reprocessing was done for DR8 on the 2008-2011 data, so the first two links above point to DR2.

Known Objects

Among the ensemble of MEarth M dwarfs included here for download, this data release includes discovery and/or characterization light curves of the super-Earth GJ1214b (=LSPMJ1715+0457), the eclipsing brown dwarf NLTT41135 (=one component of LSPMJ1546+0441, unresolved in MEarth photometry), the short-period double-lined eclipsing binary GJ3236 (=LSPMJ0337+6910), and the 41-day double-lined eclipsing binary LSPMJ1112+7626.

The light curves contributing to our samples of photometric rotation periods for Northern and Southern field M dwarfs are also contained within this data release.


If your work with these data results in a publication, please consider inviting us to join that publication as coauthors. This is not a requirement for using the data, but having put a lot of effort making MEarth data useful for public analysis, we would appreciate the courtesy. At a minimum, please cite Berta et al. (2012) as a qualitative description of the dataset and include the following statement of acknowledgement in your paper: "This paper makes use of data from the MEarth Project, which is a collaboration between Harvard University and the Smithsonian Astrophysical Observatory. The MEarth Project acknowledges funding from the David and Lucile Packard Fellowship for Science and Engineering, the National Science Foundation under grants AST-0807690, AST-1109468, AST-1616624 and AST-1004488 (Alan T. Waterman Award), and the John Templeton Foundation."