J/AJ/153/149 Broadband photometry of Neptune from K2 (Rowe+, 2017)
Time-series analysis of broadband photometry of Neptune from K2.
Rowe J.F., Gaulme P., Lissauer J.J., Marley M.S., Simon A.A., Hammel H.B.,
Silva Aguirre V., Barclay T., Benomar O., Boumier P., Caldwell D.A.,
Casewell S.L., Chaplin W.J., Colon K.D., Corsaro E., Davies G.R.,
Fortney J.J., Garcia R.A., Gizis J.E., Haas M.R., Mosser B., Schmider F.-X.
<Astron. J., 153, 149-149 (2017)>
=2017AJ....153..149R 2017AJ....153..149R (SIMBAD/NED BibCode)
ADC_Keywords: Planets ; Photometry
Keywords: planetary systems - planets and satellites: gaseous planets
Abstract:
We report here on our search for excess power in photometry of Neptune
collected by the K2 mission that may be due to intrinsic global
oscillations of the planet Neptune. To conduct this search, we
developed new methods to correct for instrumental effects such as
intrapixel variability and gain variations. We then extracted and
analyzed the time-series photometry of Neptune from 49 days of nearly
continuous broadband photometry of the planet. We find no evidence of
global oscillations and place an upper limit of ∼5ppm at 1000µHz
for the detection of a coherent signal. With an observed cadence of 1
minute and a point-to-point scatter of less than 0.01%, the
photometric signal is dominated by reflected light from the Sun, which
is in turn modulated by atmospheric variability of Neptune at the 2%
level. A change in flux is also observed due to the increasing
distance between Neptune and the K2 spacecraft and the solar
variability with convection-driven solar p modes present.
Description:
The K2 C3 field provided the first opportunity to observe the planet
Neptune for up to 80 days with short-cadence (1 minute) sampling (the
C3 campaign had an actual duration of 69.2 days, limited by on-board
data storage). We were awarded sufficient pixel allocation from Guest
Observer Programs GO3060 (PI: Rowe) and GO3057 (PI: Gaulme) to
continuously monitor Neptune for 49 days.
Short-cadence target pixel files were obtained from Mikulski Archive
for Space Telescopes (MAST). The Neptune short-cadence subraster was
spread across 161 FITS files. Each file contained 1 column of
time-series pixel data. Each target pixel file contains observations
starting on 2014 November 15 and finishing on 2015 January 18.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 28 68481 Adopted photometry
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See also:
J/ApJ/784/45 : Kepler's multiple planet candidates. III. (Rowe+, 2014)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 F11.8 d BJD [16.4/65.42] Offset Barycentric Julian Date
(BJD-2456977.10319595)
13- 20 F8.5 --- Flux [-0.0185/0.026] Adopted distance corrected
photometry
22- 28 F7.5 --- e_Flux [0.00035/0.00036] Uncertainty in Flux
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History:
From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 01-Aug-2017