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Main Authors: Decocq, Emeline, Swain, Mark, Dang, Lisa, Ciardi, David R., Bryden, Geoffrey
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2605.10427
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author Decocq, Emeline
Swain, Mark
Dang, Lisa
Ciardi, David R.
Bryden, Geoffrey
author_facet Decocq, Emeline
Swain, Mark
Dang, Lisa
Ciardi, David R.
Bryden, Geoffrey
contents We present a comparison of the two most recent and comprehensive Spitzer phase curve studies - Dang et al. (2025) and Swain et al. (2025) - which report analyses of the Spitzer 4.5 $μ$m phase curves. The studies employ different approaches for correcting instrument systematics and they also use different approaches for selecting the optimal exoplanet system parameters. To evaluate the level of consistency between the two studies, we compared the constraints on the ratio of planet-to-star radii ($R_P/R_\star$), eclipse depth ($F_P/F_\star$), phase curve amplitude ($A$), and phase curve offset ($ϕ$). We find that the two studies produce similar results at the population level although results for individual planets can vary, especially for phase curve offset values. We examined the difference of planet system parameters to see if inconsistencies in individual planet results were due to data reduction methods or system parameter choices. We also examined whether the system parameters used by both studies were consistent with Kepler's third law. During this comparison, we identified one case where stellar mass, planet semi-major axis, and orbital period did not follow Kepler's law even though the values were all compiled from the same publication. To assess whether this kind of discrepancy was recurrent, we recalculated the orbital periods using Kepler's third law and compared them with the values listed in the NASA Exoplanet Archive. Our detailed analysis of archival system parameters strongly suggests that testing reported/selected parameters for consistency with Kepler's third law is worthwhile.
format Preprint
id arxiv_https___arxiv_org_abs_2605_10427
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Comparing Results from Two Uniform Phase Curve Surveys
Decocq, Emeline
Swain, Mark
Dang, Lisa
Ciardi, David R.
Bryden, Geoffrey
Earth and Planetary Astrophysics
We present a comparison of the two most recent and comprehensive Spitzer phase curve studies - Dang et al. (2025) and Swain et al. (2025) - which report analyses of the Spitzer 4.5 $μ$m phase curves. The studies employ different approaches for correcting instrument systematics and they also use different approaches for selecting the optimal exoplanet system parameters. To evaluate the level of consistency between the two studies, we compared the constraints on the ratio of planet-to-star radii ($R_P/R_\star$), eclipse depth ($F_P/F_\star$), phase curve amplitude ($A$), and phase curve offset ($ϕ$). We find that the two studies produce similar results at the population level although results for individual planets can vary, especially for phase curve offset values. We examined the difference of planet system parameters to see if inconsistencies in individual planet results were due to data reduction methods or system parameter choices. We also examined whether the system parameters used by both studies were consistent with Kepler's third law. During this comparison, we identified one case where stellar mass, planet semi-major axis, and orbital period did not follow Kepler's law even though the values were all compiled from the same publication. To assess whether this kind of discrepancy was recurrent, we recalculated the orbital periods using Kepler's third law and compared them with the values listed in the NASA Exoplanet Archive. Our detailed analysis of archival system parameters strongly suggests that testing reported/selected parameters for consistency with Kepler's third law is worthwhile.
title Comparing Results from Two Uniform Phase Curve Surveys
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2605.10427