TY - JOUR
T1 - The LHS 1678 System
T2 - Two Earth-sized Transiting Planets and an Astrometric Companion Orbiting an M Dwarf Near the Convective Boundary at 20 pc
AU - Silverstein, Michele L.
AU - Schlieder, Joshua E.
AU - Barclay, Thomas
AU - Hord, Benjamin J.
AU - Jao, Wei Chun
AU - Vrijmoet, Eliot Halley
AU - Henry, Todd J.
AU - Cloutier, Ryan
AU - Kostov, Veselin B.
AU - Kruse, Ethan
AU - Winters, Jennifer G.
AU - Irwin, Jonathan M.
AU - Kane, Stephen R.
AU - Stassun, Keivan G.
AU - Huang, Chelsea
AU - Kunimoto, Michelle
AU - Tey, Evan
AU - Vanderburg, Andrew
AU - Astudillo-Defru, Nicola
AU - Bonfils, Xavier
AU - Brasseur, C. E.
AU - Charbonneau, David
AU - Ciardi, David R.
AU - Collins, Karen A.
AU - Collins, Kevin I.
AU - Conti, Dennis M.
AU - Crossfield, Ian J.M.
AU - Daylan, Tansu
AU - Doty, John P.
AU - Dressing, Courtney D.
AU - Gilbert, Emily A.
AU - Horne, Keith
AU - Jenkins, Jon M.
AU - Latham, David W.
AU - Mann, Andrew W.
AU - Matthews, Elisabeth
AU - Paredes, Leonardo A.
AU - Quinn, Samuel N.
AU - Ricker, George R.
AU - Schwarz, Richard P.
AU - Seager, Sara
AU - Sefako, Ramotholo
AU - Shporer, Avi
AU - Smith, Jeffrey C.
AU - Stockdale, Christopher
AU - Tan, Thiam Guan
AU - Torres, Guillermo
AU - Twicken, Joseph D.
AU - Vanderspek, Roland
AU - Wang, Gavin
AU - Winn, Joshua N.
N1 - Funding Information:
E.A.G. thanks the LSSTC Data Science Fellowship Program, which is funded by LSSTC, NSF Cybertraining Grant #1829740, the Brinson Foundation, and the Moore Foundation; her participation in the program has benefited this work. The material is based upon work supported by NASA under award number 80GSFC21M0002.
Funding Information:
This paper includes data collected with the TESS mission (Ricker et al. ), obtained from the MAST data archive at the Space Telescope Science Institute (STScI). Funding for the TESS mission is provided by NASAs Science Mission Directorate. STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 526555.
Funding Information:
The MEarth Team gratefully acknowledges funding from the David and Lucile Packard Fellowship for Science and Engineering (awarded to D.C.). This material is based upon work supported by the National Science Foundation under grant Nos. AST-0807690, AST-1109468, AST-1004488 (Alan T. Waterman Award), and AST-1616624, and upon work supported by the National Aeronautics and Space Administration under grant No. 80NSSC18K0476 issued through the XRP Program. This work is made possible by a grant from the John Templeton Foundation. The opinions expressed in this publication are those of the authors and do not necessarily reflect the views of the John Templeton Foundation.
Funding Information:
We acknowledge the use of TESS High Level Science Products (HLSP) produced by the Quick-Look Pipeline (QLP) at the TESS Science Office at MIT, which are publicly available from the Mikulski Archive for Space Telescopes (MAST). Funding for the TESS mission is provided by NASA’s Science Mission directorate.
Funding Information:
K.H. acknowledges support from STFC grant No. ST/R000824/1.
Funding Information:
N. A.-D. acknowledges the support of FONDECYT project 3180063.
Funding Information:
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.
Funding Information:
T.D. acknowledges support from MIT’s Kavli Institute as a Kavli postdoctoral fellow.
Funding Information:
This work makes use of observations from the LCOGT network. Part of the LCOGT telescope time was granted by NOIRLab through the Mid-Scale Innovations Program (MSIP). MSIP is funded by NSF.
Publisher Copyright:
© 2022. The Author(s). Published by the American Astronomical Society.
PY - 2022/4/1
Y1 - 2022/4/1
N2 - We present the Transiting Exoplanet Survey Satellite (TESS) discovery of the LHS 1678 (TOI-696) exoplanet system, comprised of two approximately Earth-sized transiting planets and a likely astrometric brown dwarf orbiting a bright (V J = 12.5, K s = 8.3) M2 dwarf at 19.9 pc. The two TESS-detected planets are of radius 0.70 ± 0.04 R ⊕ and 0.98 ± 0.06 R ⊕ in 0.86 day and 3.69 day orbits, respectively. Both planets are validated and characterized via ground-based follow-up observations. High Accuracy Radial Velocity Planet Searcher RV monitoring yields 97.7 percentile mass upper limits of 0.35 M ⊕ and 1.4 M ⊕ for planets b and c, respectively. The astrometric companion detected by the Cerro Tololo Inter-American Observatory/Small and Moderate Aperture Telescope System 0.9 m has an orbital period on the order of decades and is undetected by other means. Additional ground-based observations constrain the companion to being a high-mass brown dwarf or smaller. Each planet is of unique interest; the inner planet has an ultra-short period, and the outer planet is in the Venus zone. Both are promising targets for atmospheric characterization with the James Webb Space Telescope and mass measurements via extreme-precision radial velocity. A third planet candidate of radius 0.9 ± 0.1 R ⊕ in a 4.97 day orbit is also identified in multicycle TESS data for validation in future work. The host star is associated with an observed gap in the lower main sequence of the Hertzsprung-Russell diagram. This gap is tied to the transition from partially to fully convective interiors in M dwarfs, and the effect of the associated stellar astrophysics on exoplanet evolution is currently unknown. The culmination of these system properties makes LHS 1678 a unique, compelling playground for comparative exoplanet science and understanding the formation and evolution of small, short-period exoplanets orbiting low-mass stars.
AB - We present the Transiting Exoplanet Survey Satellite (TESS) discovery of the LHS 1678 (TOI-696) exoplanet system, comprised of two approximately Earth-sized transiting planets and a likely astrometric brown dwarf orbiting a bright (V J = 12.5, K s = 8.3) M2 dwarf at 19.9 pc. The two TESS-detected planets are of radius 0.70 ± 0.04 R ⊕ and 0.98 ± 0.06 R ⊕ in 0.86 day and 3.69 day orbits, respectively. Both planets are validated and characterized via ground-based follow-up observations. High Accuracy Radial Velocity Planet Searcher RV monitoring yields 97.7 percentile mass upper limits of 0.35 M ⊕ and 1.4 M ⊕ for planets b and c, respectively. The astrometric companion detected by the Cerro Tololo Inter-American Observatory/Small and Moderate Aperture Telescope System 0.9 m has an orbital period on the order of decades and is undetected by other means. Additional ground-based observations constrain the companion to being a high-mass brown dwarf or smaller. Each planet is of unique interest; the inner planet has an ultra-short period, and the outer planet is in the Venus zone. Both are promising targets for atmospheric characterization with the James Webb Space Telescope and mass measurements via extreme-precision radial velocity. A third planet candidate of radius 0.9 ± 0.1 R ⊕ in a 4.97 day orbit is also identified in multicycle TESS data for validation in future work. The host star is associated with an observed gap in the lower main sequence of the Hertzsprung-Russell diagram. This gap is tied to the transition from partially to fully convective interiors in M dwarfs, and the effect of the associated stellar astrophysics on exoplanet evolution is currently unknown. The culmination of these system properties makes LHS 1678 a unique, compelling playground for comparative exoplanet science and understanding the formation and evolution of small, short-period exoplanets orbiting low-mass stars.
UR - http://www.scopus.com/inward/record.url?scp=85126692140&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85126692140&partnerID=8YFLogxK
U2 - 10.3847/1538-3881/ac32e3
DO - 10.3847/1538-3881/ac32e3
M3 - Article
AN - SCOPUS:85126692140
SN - 0004-6256
VL - 163
JO - Astronomical Journal
JF - Astronomical Journal
IS - 4
M1 - 151
ER -