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Spitzer Secondary Eclipse Depths with Multiple Intrapixel Sensitivity Correction Methods: Observations of WASP-13b, WASP-15b, WASP-16b, WASP-62b, and HAT-P-22b

Kilpatrick, Brian M. and Lewis, Nikole K. and Kataria, Tiffany and Deming, Drake and Ingalls, James G. and Krick, Jessica E. and Tucker, Gregory S. (2017) Spitzer Secondary Eclipse Depths with Multiple Intrapixel Sensitivity Correction Methods: Observations of WASP-13b, WASP-15b, WASP-16b, WASP-62b, and HAT-P-22b. Astronomical Journal, 153 (1). Art. No. 22. ISSN 1538-3881.

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We measure the 4.5 μm thermal emission of five transiting hot Jupiters, WASP-13b, WASP-15b, WASP-16b, WASP-62b, and HAT-P-22b using channel 2 of the Infrared Array Camera (IRAC) on the Spitzer Space Telescope. Significant intrapixel sensitivity variations in Spitzer IRAC data require careful correction in order to achieve precision on the order of several hundred parts per million (ppm) for the measurement of exoplanet secondary eclipses. We determine eclipse depths by first correcting the raw data using three independent data reduction methods. The Pixel Gain Map (PMAP), Nearest Neighbors (NNBR), and Pixel Level Decorrelation (PLD) each correct for the intrapixel sensitivity effect in Spitzer photometric time-series observations. The results from each methodology are compared against each other to establish if they reach a statistically equivalent result in every case and to evaluate their ability to minimize uncertainty in the measurement. We find that all three methods produce reliable results. For every planet examined here NNBR and PLD produce results that are in statistical agreement. However, the PMAP method appears to produce results in slight disagreement in cases where the stellar centroid is not kept consistently on the most well characterized area of the detector. We evaluate the ability of each method to reduce the scatter in the residuals as well as in the correlated noise in the corrected data. The NNBR and PLD methods consistently minimize both white and red noise levels and should be considered reliable and consistent. The planets in this study span equilibrium temperatures from 1100 to 2000 K and have brightness temperatures that require either high albedo or efficient recirculation. However, it is possible that other processes such as clouds or disequilibrium chemistry may also be responsible for producing these brightness temperatures.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Kilpatrick, Brian M.0000-0003-4220-600X
Lewis, Nikole K.0000-0002-8507-1304
Kataria, Tiffany0000-0003-3759-9080
Deming, Drake0000-0001-5727-4094
Ingalls, James G.0000-0003-4714-1364
Tucker, Gregory S.0000-0002-6954-6947
Additional Information:© 2016. The American Astronomical Society. Received 2016 July 14; revised 2016 November 14; accepted 2016 November 22; published 2016 December 21. BMK acknowledges Brown University for its financial support of his contributions to this work. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. We also acknowledge that part of this work was completed at the Space Telescope Science Institute (STScI) operated by AURA, Inc. This research has made use of the Exoplanet Orbit Database and the Exoplanet Data Explorer at
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Brown UniversityUNSPECIFIED
Subject Keywords:atmospheric effects; methods: numerical; planets and satellites: atmospheres; planets and satellites: detection; techniques: photometric
Issue or Number:1
Record Number:CaltechAUTHORS:20170213-152013719
Persistent URL:
Official Citation:Brian M. Kilpatrick et al 2017 AJ 153 22
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:74267
Deposited By: George Porter
Deposited On:13 Feb 2017 23:39
Last Modified:13 Nov 2019 20:02

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