J/ApJ/754/136 Light curves of HD 149026b in 3.6-16um (Stevenson+, 2012)
Transit and eclipse analyses of the exoplanet HD 149026b using BLISS mapping.
Stevenson K.B., Harrington J., Fortney J.J., Loredo T.J., Hardy R.A.,
Nymeyer S., Bowman W.C., Cubillos P., Bowman M.O., Hardin M.
<Astrophys. J., 754, 136 (2012)>
=2012ApJ...754..136S 2012ApJ...754..136S
ADC_Keywords: Stars, double and multiple ; Photometry, infrared ; Planets
Keywords: planetary systems; stars: individual: HD 149026;
techniques: photometric
Abstract:
The dayside of HD 149026b is near the edge of detectability by the
Spitzer Space Telescope. We report on 11 secondary-eclipse events at
3.6, 4.5, 3x5.8, 4x8.0, and 2x16µm plus three primary-transit
events at 8.0µm. The eclipse depths from jointly fit models at each
wavelength are 0.040%±0.003% at 3.6µm, 0.034%±0.006% at
4.5µm, 0.044%±0.010% at 5.8µm, 0.052%±0.006% at 8.0µm,
and 0.085%±0.032% at 16µm. Multiple observations at the longer
wavelengths improved eclipse-depth signal-to-noise ratios by up to a
factor of two and improved estimates of the planet-to-star radius
ratio (Rp/R{sstarf}=0.0518±0.0006). We also identify no
significant deviations from a circular orbit and, using this model,
report an improved period of 2.8758916±0.0000014 days.
Chemical-equilibrium models find no indication of a temperature
inversion in the dayside atmosphere of HD 149026b. Our best-fit model
favors large amounts of CO and CO2, moderate heat redistribution
(f=0.5), and a strongly enhanced metallicity. These analyses use
BiLinearly-Interpolated Subpixel Sensitivity (BLISS) mapping, a new
technique to model two position-dependent systematics (intrapixel
variability and pixelation) by mapping the pixel surface at high
resolution. BLISS mapping outperforms previous methods in both speed
and goodness of fit. We also present an orthogonalization technique
for linearly correlated parameters that accelerates the convergence of
Markov chains that employ the Metropolis random walk sampler.
Description:
We observed secondary eclipses of HD 149026b at 3.6, 4.5, 5.8, and
8.0um with the Spitzer Infrared Array Camera (IRAC) and at 16um using
the Infrared Spectrograph's (IRS) photometric blue peak-up array. The
program also observed a primary transit at 8.0um. Including the
four previously analyzed data sets labeled in Table 1, we present 14
observations spanning more than 3.5 years, from 2005 Aug 24 to 2009
Mar 22.
Objects:
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RA (2000) DE Designation(s) (Period)
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16 30 29.62 +38 20 50.3 HD 149026b = HD 149026b (P=2.875892)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 133 14 Observation information
fits/* . 14 Light curves of HD 149026b, in FITS format, in
Spitzer/IRAC 3.6, 4.5, 5.8, 8.0um, and IRS 16um
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See also:
J/A+A/552/A119 : Planet-star and moon-planet interaction (Saur+, 2013)
J/A+A/527/A140 : Mass limits on substellar companions (Reffert+, 2011)
J/MNRAS/414/1278 : Eccentricities of transiting planets (Pont+, 2011)
J/MNRAS/411/L46 : Exoplanet magnetic fields (Vidotto+, 2011)
J/AJ/141/11 : Spitzer obs. of planet-host stars (Dodson-Robinson+, 2011)
J/ApJ/733/68 : Exoplanet masses derived from RVs (Brown+, 2011)
J/ApJ/716/1336 : Stability analysis of single-planet (Kopparapu+, 2010)
J/ApJ/705/1226 : Planet-bearing stars in Spitzer (Bryden+, 2009)
J/ApJ/700/L73 : Photospheric fluxes at 24 and 70µm (Kospal+, 2009)
J/ApJ/692/L9 : Tidal evolution of transiting exoplanets (Levrard+, 2009)
J/ApJ/675/1531 : Transits of super-Neptune HD 149026b (Winn+, 2008)
J/ApJ/666/475 : Extrasolar planet taxonomy (Marchi+, 2007)
J/ApJ/649/1010 : Habitability of known exoplanetary systems (Jones+, 2006)
J/ApJ/646/505 : Catalog of nearby exoplanets (Butler+, 2006)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Label Observation label (HD149b[p/s]NN) (1)
11- 21 A11 "YYYY/MM/DD" Date Observation date
23- 25 I3 min Dur [330/499] Duration
27- 30 F4.1 s Exp [0.4/14] Frame exposure time
32- 36 I5 --- Nfr [1050/70000] Total number of frames
38- 45 A8 --- Pipeline Spitzer pipeline ("S18.7.0" or "S18.18.0")
47- 50 F4.1 um lambda [3.6/16] Observation wavelength
52- 58 A7 --- Ref Previous publications (2)
60- 72 F13.7 d MJD MJD date of observation at start
(JD-2400000.5) (3)
74-133 A60 --- FileName Name of FITS file in subdirectory fits (3)
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Note (1): HD149b designates the planet, p/s specifies primary transit or
secondary eclipse, and "NN" identifies the wavelength and
observation number.
Note (2): Reference as follows:
H07 = Harrington et al. (2007Natur.447..691H 2007Natur.447..691H);
N09 = Nutzman et al. (2009ApJ...692..229N 2009ApJ...692..229N);
C09 = Carter et al. (2009ApJ...696..241C 2009ApJ...696..241C);
K09 = Knutson et al. (2009ApJ...703..769K 2009ApJ...703..769K).
Note (3): Columns added by CDS.
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 05-Mar-2014