J/A+A/640/A32 WASP-148 velocity curve (Hebrard+, 2020)
Discovery and characterization of the exoplanets WASP-148b and c.
A transiting system with two interacting giant planets.
Hebrard G., Diaz R.F., Correia A.C.M., Collier Cameron A., Laskar J.,
Pollacco D., Almenara J.-M., Anderson D.R., Barros S.C.C., Boisse I.,
Bonomo A.S., Bouchy F., Boue G., Boumis P., Brown D.J.A., Dalal S.,
Deleuil M., Demangeon O., Doyle A.P., Haswell C.A., Hellier C., Osborn H.,
Kiefer F., Kolb U.C., Lam K., Lecavelier des Etangs A., Lopez T.,
Martin-Lagarde M., Maxted P., McCormac J., Nielsen L.D., Palle E.,
Prieto-Arranz J., Queloz D., Santerne A., Smalley B., Turner O., Udry S.,
Verilhac D., West R., Wheatley P.J., Wilson P.A.
<Astron. Astrophys. 640, A32 (2020)>
=2020A&A...640A..32H 2020A&A...640A..32H (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Radial velocities
Keywords: planetary systems - techniques: radial velocities -
techniques: photometric - techniques: spectroscopic -
Abstract:
We present the discovery and characterization of WASP-148, a new
extrasolar system that includes at least two giant planets. The
host star is a slowly rotating inactive late-G dwarf with a
V=12 magnitude. The planet WASP-148b is a hot Jupiter of 0.72RJup
and 0.29MJup that transits its host with an orbital period of
8.80-days. We found the planetary candidate with the SuperWASP
photometric survey, then characterized it with the SOPHIE
spectrograph. Our radial velocity measurements subsequently revealed a
second planet in the system, WASP-148c, with an orbital period of
34.5-days and a minimum mass of 0.40MJup. No transits of this outer
planet were detected. The orbits of both planets are eccentric and
fall near the 4:1 mean-motion resonances. This configuration is stable
on long timescales, but induces dynamical interactions so that the
orbits differ slightly from purely Keplerian orbits. In particular,
WASP-148b shows transit-timing variations of typically 15 minutes,
making it the first interacting system with transit-timing variations
that is detected on ground-based light curves. We establish that the
mutual inclination of the orbital plane of the two planets cannot be
higher than 35, and the true mass of WASP-148c is below 0.60MJup. We
present photometric and spectroscopic observations of this system that
cover a time span of ten years. We also provide their Keplerian and
Newtonian analyses; these analyses should be significantly improved
through future TESS observations.
Description:
Located on La Palma in the Canary Islands, Spain, SuperWASPNorth
consists of eight Canon 200mm f/1.8 focal lenses coupled to e2v
20482048 pixel CCDs with 13.7" pixels and a field of view of
7.8°x7.8°, associated with a custom-built photometric
reduction pipeline. It observes with a broadband filter (400-700nm),
and secured thousands of photometric points over several seasons per
star. Periodic signatures of possible planetary transits are
identified in these light curves using the algorithms presented by
Collier Cameron et al. (2006MNRAS.373..799C 2006MNRAS.373..799C). With this facility and
procedure, WASP-148 was identified as the host star of a promising
candidate for a transiting planet.
After its identification from SuperWASP photometry, we started an RV
follow-up of WASP-148 with the SOPHIE spectrograph at the 1.93m
telescope of the Observatoire Haute-Provence, France.
Objects:
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RA (2000) DE Designation(s)
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16 56 31.34 +44 18 09.5 WASP-148 = 2MASS J16563135+4418095
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 49 116 SOPHIE measurements of WASP-148
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 9 F9.4 d BJD Barycentric Julian Day (UTC) of the measurement
(BJD-2450000)
13- 18 F6.3 km/s RV Radial velocity
22- 26 F5.3 km/s e_RV 1-sigma uncertainty of the radial velocity
30- 35 F6.3 km/s BIS Bisector span
39- 42 I4 s TimeExp Exposure time
46- 49 F4.1 --- S/N Signal-to-noise ratio per pixel at 550nm
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Acknowledgements:
Guillaume Hebrard, hebrard(at)iap.fr
(End) Patricia Vannier [CDS] 21-Jul-2020