TESS FFI search of 46,947 fast-rotating red dwarfs within 150 pc finds 104 new complex periodic variable candidates; the census grows 1.2-1.5x within 50 pc and 2.7-2.9x within 100 pc, not 2x and 10x

Question: Complex periodic variables (CPVs) are young M dwarfs with sharp dips that repeat at the rotation period. Bouma et al. (2024; B24) found CPVs in TESS 2-minute data and predicted that a full-frame-image (FFI) search would increase the CPV census by a factor of 2 within 50 pc and 10 within 100 pc. We tested this prediction. Approach: We searched the TARS FFI light curves of 46,947 red dwarfs (BP-RP > 1.5, M_G > 4, T < 16, d < 150 pc, TARS period < 2 d; 122,351 star-sectors, Sectors 1-96). We counted the dips in each phase curve and required the same shape in the two halves of the sector. These cuts flag 44% of the sectors of known CPVs and 0.75% of random stars. We examined the flagged stars by eye, and then classified 171 stars again with hidden identities. We located each signal in the TESS pixels and measured youth with the CMD, BANYAN Sigma and member lists. Findings: We kept 153 CPVs. 27 are in B24, 22 are in other papers and 104 are new candidates (98 on target). Only 1 new candidate is within 50 pc, and 24 are within 100 pc. 90% of the new candidates have a youth indicator. Capture-recapture with the B24 sample gives census growth factors of 1.24 +/- 0.12 within 50 pc and 2.67 +/- 0.38 within 100 pc. The prediction is too large because it uses the 2-minute coverage of all parent stars at the outer distance. CPVs are young and over-luminous, thus they are bright at a given distance and got 2-minute data more frequently: 10 of 10 CPVs within 50 pc and 18 of 41 within 100 pc have 2-minute data, but only 57% and 22% of the parent stars have these data. Parent stars matched in T, distance and CMD height (dMG > 0.5 mag) predict factors of 1.49 and 2.87. These values agree with capture-recapture. Limitations: Spectra do not confirm the candidates. One person did the visual vetting. Capture-recapture assumes independent searches, but both searches prefer large-amplitude CPVs. Some candidates can be eclipsing binaries, and 6 new candidates are not on target. The package contains the code, tables, figures and reproduction steps.

complex periodic variables · M dwarfs · TESS full-frame images · TARS light curves · stellar rotation · young stars · scallop-shell stars · persistent flux dips · capture-recapture · selection effects · survey completeness · solar neighbourhood census · TESS 2-minute target selection · BANYAN Sigma · Gaia DR3 · pixel-level localisation · eclipsing binary contamination · blind vetting · variable star search

Admitted 2026-11-09 08:00 UTC5 citing publications

References

challengesdoi:10.3847/1538-3881/ad0c4c
B24 predicted that an FFI search would grow the CPV census by about 2x within 50 pc and 10x within 100 pc. Our FFI search and capture-recapture give 1.24 +/- 0.12 and 2.67 +/- 0.38. Matched parent stars give 1.49 and 2.87. We also use the B24 sample limits, CPV table (calibration and literature status) and 2-minute sector range.
usesdoi:10.3847/1538-4365/ae6657
TARS paper. We use its FFI light curves, periods and sector lists for the search.
usesdoi:10.17909/2sff-fn29
TARS HLSP at MAST. We read all FFI light curves from it.
usesdoi:10.5281/zenodo.19917941
TARS Table 2 (feather file). We use it to make the search list.
usesdoi:10.1117/1.JATIS.1.1.014003
TESS mission. All light curves and cutouts are TESS data.
usesdoi:10.1051/0004-6361/202243940
Gaia DR3. We use its astrometry, photometry and neighbour lists.
usesdoi:10.3847/1538-4357/aaae09
BANYAN Sigma. We use it for kinematic membership in young groups.
usesdoi:10.1051/0004-6361/202346285
Hunt & Reffert 2023 cluster members. We use them as a youth indicator.
usesdoi:10.3847/1538-4357/ac0251
Kerr et al. 2021 young-star members. We use them as a youth indicator.
usesdoi:10.1088/0067-0049/208/1/9
Pecaut & Mamajek 2013 dwarf sequence. We use it to calculate the height above the main sequence.
usesdoi:10.3847/0004-6256/152/5/114
Rebull et al. 2016. We use its table for the literature cross-match.
usesdoi:10.3847/1538-3881/aab605
Rebull et al. 2018. We use its table for the literature cross-match.
usesdoi:10.3847/1538-3881/ab893c
Rebull et al. 2020. We use its table for the literature cross-match.
usesdoi:10.3847/1538-3881/ac75f1
Rebull et al. 2022. We use its scallop flags and notes to set the literature status.
usesdoi:10.3847/1538-4357/acb055
Popinchalk et al. 2023. We use its table for the literature cross-match.
usesdoi:10.3847/1538-3881/aa5eb9
Stauffer et al. 2017 CPV (scallop-shell) stars. We use them to set the literature status.
usesdoi:10.3847/1538-3881/aaa19d
Stauffer et al. 2018 CPV stars. We use them to set the literature status.
usesdoi:10.3847/1538-3881/abc7c6
Stauffer et al. 2021 CPV stars. We use them to set the literature status.
usesdoi:10.3847/1538-4357/ab158c
Zhan et al. 2019 CPV stars. We use them to set the literature status.
usesdoi:10.3847/1538-3881/ac503c
Gunther et al. 2022 CPV stars. We use them to set the literature status.
usesdoi:10.3847/2041-8213/ade39a
Bouma & Jardine 2025. We use it in the SIMBAD search for CPV papers.
usesdoi:10.3847/1538-4365/ac324a
Prsa et al. 2022 TESS eclipsing binaries. We flag candidates that are in this catalogue.
usesdoi:10.1051/0004-6361/202245330
Mowlavi et al. 2023 Gaia DR3 eclipsing binaries. We flag candidates that are in this catalogue.
usesdoi:10.1093/mnras/stad915
Green et al. 2023 TESS eclipsing binaries. We flag candidates that are in this catalogue.
usesdoi:10.1017/pasa.2024.72
Driessen et al. 2024 radio stars. We flag candidates that are in this catalogue.
usesdoi:10.3847/2041-8213/ae6ef6
Wang et al. 2026. TIC 365466012 is the optical counterpart of its radio source ASKAP J181335-604720.

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Public catalog entries on Sciscape.

usesThe mean AllWISE W1−W2 contrast has a 95% upper bound of 0.0128 mag for 23 CPV pairs under a t model with independent pairs
The fixed pairs inherit CPV labels and TESS search coverage from this census.
usesGaia DR3 RUWE is above 2 for 7 of 69 CPV candidates and 8 of 69 matched rapid rotators in young groups
We reuse its CPV census, visual labels, pixel localisation, and known-candidate exclusions.
usesRotation alone does not explain CPV youth: M dwarfs (P < 2 d, d < 150 pc) in groups older than 60 Myr have 3 complex periodic variables where 30 are expected for their period, colour, T and sectors
Our TESS FFI census. We use its 46,947 parent stars, their periods, sectors and T magnitudes, and its 153 CPVs.
usesComplex periodic M dwarfs within 150 pc are RACS/VLASS radio sources 3-8 times more often than matched young rapid rotators, also at equal X-ray luminosity, but are not more often eRASS1 X-ray sources
Source of the 46,947 parent stars, the 153 CPVs (class, literature status, youth flags, radio catalogue flags) and the vetted candidate list that defines the excluded group.
usesGaia DR3 data show six candidate stellar pairs at 500–10,000 au among 146 on-target complex periodic variable entries
The unchanged 153-entry TESS FFI census supplies CPV labels and localization flags.