J/A+A/601/A117 Spitzer search for 19 planets (Gillon+, 2017)
The Spitzer search for the transits of HARPS low-mass planets.
II. Null results for 19 planets.
Gillon M., Demory B.-O., Lovis C., Deming D., Ehrenreich D., Lo Curto G.,
Mayor M., Pepe F., Queloz D., Seager S., Segransan D., Udry S.
<Astron. Astrophys. 601, A117 (2017)>
=2017A&A...601A.117G 2017A&A...601A.117G (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing ; Planets ; Photometry, infrared ;
Radial velocities
Keywords: binaries: eclipsing - planetary systems - stars: general -
techniques: radial velocities - techniques: photometric
Abstract:
Short-period super-Earths and Neptunes are now known to be very
frequent around solar-type stars. Improving our understanding of these
mysterious planets requires the detection of a significant sample of
objects suitable for detailed characterization. Searching for the
transits of the low-mass planets detected by Doppler surveys is a
straightforward way to achieve this goal. Indeed, Doppler surveys
target the most nearby main-sequence stars, they regularly detect
close-in low-mass planets with significant transit probability, and
their radial velocity data constrain strongly the ephemeris of
possible transits. In this context, we initiated in 2010 an ambitious
Spitzer multi-Cycle transit search project that targeted 25 low-mass
planets detected by radial velocity, focusing mainly on the
shortest-period planets detected by the HARPS spectrograph. We report
here null results for 19 targets of the project. For 16 planets out of
19, a transiting configuration is strongly disfavored or firmly
rejected by our data for most planetary compositions.We derive a
posterior probability of 83% that none of the probed 19 planets
transits (for a prior probability of 22%), which still leaves a
significant probability of 17% that at least one of them does transit.
Globally, our Spitzer project revealed or confirmed transits for three
of its 25 targeted planets, and discarded or disfavored the transiting
nature of 20 of them. Our light curves demonstrate for Warm Spitzer
excellent photometric precisions: for 14 targets out of 19, we were
able to reach standard deviations that were better than 50ppm per 30
min intervals. Combined with its Earth-trailing orbit, which makes it
capable of pointing any star in the sky and to monitor it continuously
for days, this work confirms Spitzer as an optimal instrument to
detect sub-mmag-deep transits on the bright nearby stars targeted by
Doppler surveys.
Description:
Files rv.dat and the phot/* files contain, respectively, the
radial velocity and photometric time-series supporting the work
presented in the paper.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 131 24 24 of the 25 planets targeted by our Spitzer
multi-cycle transit search
rv.dat 93 3720 Radial velocities
phot/* . 40 Individual Spitzer photometry files
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See also:
J/A+A/518/A25 : Transits of HD40307b by Spitzer (Gillon+, 2010)
J/A+A/528/A111 : GJ3634 radial velocity and 4.5um flux (Bonfils+, 2011)
J/A+A/533/A114 : Transit of super-Earth 55 Cnc e (Demory+, 2011)
J/A+A/539/A28 : New transit photometry for super-Earth 55 Cnc e (Gillon+ 2012)
J/A+A/584/A72 : Transiting rocky planet at 6.5pc from the Sun (Motalebi+ 2015)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Planet Planet name (1)
13- 15 A3 --- r_Planet Reference (4)
17- 20 F4.2 Msun Ms Star mass
22- 25 F4.1 pc d Distance
27- 30 F4.2 mag Kmag K magnitude
32- 35 F4.1 Mgeo Mpsini Planet mass (Mp*sini)
37- 39 I3 ppm Det1 ?=- Mean transit detection threshold in part
per million (2)
40 A1 --- --- [/]
41- 44 F4.2 Rgeo Det2 ?=- Mean transit detection threshold in Earth
radius (2)
45 A1 --- n_Det1 [a] Note when not applicable (3)
47- 50 F4.2 Rgeo radPF Theoretical radius corresponding to a
pure-iron composition
52- 55 F4.2 Rgeo radEl Theoretical radius corresponding to an
Earth-like composition
57- 60 F4.1 % PPrior A priori (geometric) transit probabilities for
the planet, P(tr)
62- 67 F6.2 % PPost A posteriori (after observation) transit
probabilities for the planet, P(tr,D)
69- 77 F9.6 d Per ? Period
79- 86 F8.6 d e_Per ? rms uncertainty on Per
88-101 A14 --- FileName1 Name of the file with Spitzer photometry
(AOR 1) or general in no other files
in subdirectory phot
103-116 A14 --- FileName2 Name of the file with Spitzer photometry
(AOR 2) in subdirectory phot
118-131 A14 --- FileName3 Name of the file with Spitzer photometry
(AOR 3) in subdirectory phot
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Note (1): The first group of 5 planets are the targets for which results were
presented previously. The second group of 19 planets are the targets of this
work.
Note (2): as inferred from injection of transit models in the data
(see Sec. 6 for details)
Note (3): a: Not Applicable: for HD13808 b and HD115617 b (61 Vir b), our
observations did not constrain the (non-)transiting configuration, while for
HD75732 e (55 Cnc e), HD97658 b, and HD219134 b, a transit was firmly detected
in the data.
Note (4): References as follows
1 = Gillon et al., 2010, Cat. J/A+A/518/A25
2 = Bonfils et al., 2011, Cat. J/A+A/528/A111
3 = Demory et al., 2011, Cat. J/A+A/533/A114
4 = Gillon et al., 2012a, Cat. J/A+A/539/A28
5 = Van Grootel et al., 2014ApJ...786....2V 2014ApJ...786....2V
6 = Motalebi et al., 2015, Cat. J/A+A/584/A72
7 = this work
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Byte-by-byte Description of file: rv.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name Star name
11- 28 F18.13 d BJD Barycentric Julian date (BJD-2450000) (TDB)
30- 38 F9.5 km/s RV ? Absolute radial velocity (1)
40- 47 F8.5 km/s dRV ? Relative radial velocity (1)
49- 55 F7.5 km/s e_RV rms uncertainty on RV or dRV
57- 63 F7.5 km/s FWHM ?=0 FWHM span of the CCF
65- 70 F6.3 km/s Contrast ?=0 Contrast span of the CCF
72- 79 F8.5 km/s Span ?=0 Bisector span of the CCF
81- 87 F7.4 --- logR'(HK) ?=0 logR'(HK) activity indicator
89- 93 A5 --- Inst Instrument (2)
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Note (1): Absolute radial velocities for HARPS measurements,
relative radial velocities for other instruments.
Note (2): Instruments are HARPS, Keck, AAT and PFS.
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Byte-by-byte Description of file: phot/*
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Bytes Format Units Label Explanations
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1- 18 F18.13 d BJD Barycentric Julian date (BJD-2450000) UTC
20- 38 F19.17 --- Fnorm Normalized flux
40- 63 E24.18 --- e_Fnorm Normalized flux error
65- 82 F18.15 pix Xpos PSF center x-position (pixels)
84-101 F18.15 pix Ypos PSF center y-position (pixels)
103-120 F18.16 pix FWHMx PSF FWHM x-direction (pixels)
122-139 F18.16 pix FWHMy PSF FWHM y-direction (pixels)
141-158 F18.16 pix FWHM PSF FWHM (pixels)
160-179 F20.17 --- Back Background (el)
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Acknowledgements:
Michael Gillon, michael.gillon(at)ulg.ac.be
References:
Gillon et al., Paper I 2010A&A...518A..25G 2010A&A...518A..25G, Cat. J/A+A/518/A25
(End) Patricia Vannier [CDS] 09-Jan-2017