TY - JOUR
T1 - Complex Modulation of Rapidly Rotating Young M Dwarfs
T2 - Adding Pieces to the Puzzle
AU - Günther, Maximilian N.
AU - Berardo, David A.
AU - Ducrot, Elsa
AU - Murray, Catriona A.
AU - Stassun, Keivan G.
AU - Olah, Katalin
AU - Bouma, L. G.
AU - Rappaport, Saul
AU - Winn, Joshua N.
AU - Feinstein, Adina D.
AU - Matthews, Elisabeth C.
AU - Sebastian, Daniel
AU - Rackham, Benjamin V.
AU - Seli, Bálint
AU - Amaury, Amaury H.M.
AU - Gillen, Edward
AU - Levine, Alan M.
AU - Demory, Brice Olivier
AU - Gillon, Michaël
AU - Queloz, Didier
AU - Ricker, George R.
AU - Vanderspek, Roland K.
AU - Seager, Sara
AU - Latham, David W.
AU - Jenkins, Jon M.
AU - Brasseur, C. E.
AU - Colón, Knicole D.
AU - Daylan, Tansu
AU - Delrez, Laetitia
AU - Fausnaugh, Michael
AU - Garcia, Lionel J.
AU - Jayaraman, Rahul
AU - Jehin, Emmanuel
AU - Kristiansen, Martti H.
AU - Kruijssen, J. M.Diederik
AU - Pedersen, Peter Pihlmann
AU - Pozuelos, Francisco J.
AU - Rodriguez, Joseph E.
AU - Wohler, Bill
AU - Zhan, Zhuchang
N1 - Funding Information:
M.N.G. acknowledges support from MIT’s Kavli Institute as a Juan Carlos Torres Fellow and from the European Space Agency (ESA) as an ESA Research Fellow. K.O. and B.S. acknowledge support from the Hungarian National Research, Development and Innovation Office grant OTKA K131508. B.S. is supported by the ÚNKP-19-3 New National Excellence Program of the Ministry for Innovation and Technology. J.N.W. and B.V.R. thank the Heising-Simons Foundation for support. A.D.F. acknowledges the support from the National Science Foundation Graduate Research Fellowship Program under grant No. (DGE-1746045). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. E.G. gratefully acknowledges support from the David and Claudia Harding Foundation in the form of a Winton Exoplanet Fellowship. M.G. is F.R.S.-FNRS Senior Research Associate. B.-O.D. acknowledges support from the Swiss National Science Foundation (PP00P2-163967). J.M.D.K. gratefully acknowledges funding from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) through an Emmy Noether Research Group (grant number KR4801/1-1), the DFG Sachbeihilfe (grant number KR4801/2-1), and the SFB 881 “The Milky Way System” (subproject B2), as well as from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program via the ERC Starting Grant MUSTANG (grant agreement number 714907).
Funding Information:
Funding for the TESS mission is provided by NASA’s Science Mission directorate. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. This paper includes data collected by the TESS mission, which are publicly available from the Mikulski Archive for Space Telescopes (MAST). STScI is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS 5-26555. The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007–2013) ERC Grant Agreement n° 336480, from the European Union’s Horizon 2020 research and innovation program (grant agreement n° 803193/BEBOP), from the ARC grant for Concerted Research Actions financed by the Wallonia-Brussels Federation, from the Balzan Prize Foundation, from F.R.S-FNRS (Research Project ID T010920F), from the Simons Foundation, from the MERAC foundation, and from STFC, under grant number ST/S00193X/1. This work has made use of data from the European Space Agency (ESA) mission Gaia ( https://www.cosmos.esa.int/gaia ), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium ). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement.
Publisher Copyright:
© 2022. The Author(s). Published by the American Astronomical Society.
PY - 2022/4/1
Y1 - 2022/4/1
N2 - New sets of young M dwarfs with complex, sharp-peaked, and strictly periodic photometric modulations have recently been discovered with Kepler/K2 (scallop shells) and TESS (complex rotators). All are part of star-forming associations, are distinct from other variable stars, and likely belong to a unified class. Suggested hypotheses include starspots, accreting dust disks, corotating clouds of material, magnetically constrained material, spots and misaligned disks, and pulsations. Here, we provide a comprehensive overview and add new observational constraints with TESS and SPECULOOS Southern Observatory photometry. We scrutinize all hypotheses from three new angles: (1) We investigate each scenario's occurrence rates via young star catalogs, (2) we study the feature's longevity using over one year of combined data, and (3) we probe the expected color dependency with multicolor photometry. In this process, we also revisit the stellar parameters accounting for activity effects, study stellar flares as activity indicators over year-long timescales, and develop toy models to simulate typical morphologies. We rule out most hypotheses, and only (i) corotating material clouds and (ii) spots and misaligned disks remain feasible-with caveats. For (i), corotating dust might not be stable enough, while corotating gas alone likely cannot cause percentage-scale features and (ii) would require misaligned disks around most young M dwarfs. We thus suggest a unified hypothesis, a superposition of large-amplitude spot modulations and sharp transits of corotating gas clouds. While the complex rotators' mystery remains, these new observations add valuable pieces to the puzzle going forward.
AB - New sets of young M dwarfs with complex, sharp-peaked, and strictly periodic photometric modulations have recently been discovered with Kepler/K2 (scallop shells) and TESS (complex rotators). All are part of star-forming associations, are distinct from other variable stars, and likely belong to a unified class. Suggested hypotheses include starspots, accreting dust disks, corotating clouds of material, magnetically constrained material, spots and misaligned disks, and pulsations. Here, we provide a comprehensive overview and add new observational constraints with TESS and SPECULOOS Southern Observatory photometry. We scrutinize all hypotheses from three new angles: (1) We investigate each scenario's occurrence rates via young star catalogs, (2) we study the feature's longevity using over one year of combined data, and (3) we probe the expected color dependency with multicolor photometry. In this process, we also revisit the stellar parameters accounting for activity effects, study stellar flares as activity indicators over year-long timescales, and develop toy models to simulate typical morphologies. We rule out most hypotheses, and only (i) corotating material clouds and (ii) spots and misaligned disks remain feasible-with caveats. For (i), corotating dust might not be stable enough, while corotating gas alone likely cannot cause percentage-scale features and (ii) would require misaligned disks around most young M dwarfs. We thus suggest a unified hypothesis, a superposition of large-amplitude spot modulations and sharp transits of corotating gas clouds. While the complex rotators' mystery remains, these new observations add valuable pieces to the puzzle going forward.
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U2 - 10.3847/1538-3881/ac503c
DO - 10.3847/1538-3881/ac503c
M3 - Article
AN - SCOPUS:85126081983
SN - 0004-6256
VL - 163
JO - Astronomical Journal
JF - Astronomical Journal
IS - 4
M1 - 144
ER -