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An Updated Ephemeris for K2-138 d

Boyle, Andrew and Christiansen, Jessie L. and Vissapragada, Shreyas and Hardegree-Ullman, Kevin K. (2022) An Updated Ephemeris for K2-138 d. Research Notes of the AAS, 6 (4). Art. No. 71. ISSN 2515-5172. doi:10.3847/2515-5172/ac64fe.

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K2-138 d (EPIC 245950175 d) is one of five planets in a chain of 3:2 mean motion resonances discovered by Christiansen et al. in K2 Campaign 12. An additional planet, confirmed with the Spitzer Space Telescope by Hardegree-Ullman et al., is not in the resonant chain. The near first-order resonances, coupled with the planets being locked in a set of three-body Laplace resonances, make this system a unique target to study for transit timing variations (TTVs). As the predicted transit timing amplitude (∼7 minutes) was below the typical transit timing uncertainty (∼10 minutes) of the K2 data, Christiansen et al. were unable to detect TTVs for K2-138 d in the K2 time series. Here, we describe new observations that allow us to refine the ephemeris for K2-138 d and perform a brief search for TTVs. Our efforts result in a refined orbital period that is 19 times more precise than previously available measurements, but our data are insufficient to confirm a TTV signal for K2-138 d.

Item Type:Article
Related URLs:
URLURL TypeDescription
Boyle, Andrew0000-0001-6037-2971
Christiansen, Jessie L.0000-0002-8035-4778
Vissapragada, Shreyas0000-0003-2527-1475
Hardegree-Ullman, Kevin K.0000-0003-3702-0382
Additional Information:© 2022. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
Group:Infrared Processing and Analysis Center (IPAC)
Subject Keywords:Exoplanets; Transit timing variation method; Exoplanet astronomy; Exoplanet detection methods; Exoplanet systems
Issue or Number:4
Record Number:CaltechAUTHORS:20220412-268547300
Persistent URL:
Official Citation:Andrew Boyle et al 2022 Res. Notes AAS 6 71
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:114231
Deposited By: Tony Diaz
Deposited On:12 Apr 2022 16:48
Last Modified:12 Apr 2022 16:48

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