J/AJ/159/242 Velocities and transit times in the Kepler-88 system (Weiss+, 2020)
The discovery of the long-period, eccentric planet Kepler-88 d and system
characterization with radial velocities and photodynamical analysis.
Weiss L.M., Fabrycky D.C., Agol E., Mills S.M., Howard A.W., Isaacson H.,
Petigura E.A., Fulton B., Hirsch L., Sinukoff E.
<Astron. J., 159, 242 (2020)>
=2020AJ....159..242W 2020AJ....159..242W
ADC_Keywords: Exoplanets; Stars, variable; Radial velocities; Spectra, optical
Keywords: Exoplanet astronomy ; Exoplanets ; Exoplanet systems ;
Exoplanet detection methods
Abstract:
We present the discovery of Kepler-88d (Pd=1403±14days,
Msinid=965±44M⊕=3.04±0.13MJ, ed=0.41±0.03)
based on six years of radial velocity (RV) follow-up from the W.M.Keck
Observatory High Resolution Echelle Spectrometer spectrograph.
Kepler-88 has two previously identified planets. Kepler-88b
(KOI-142.01) transits in the NASA Kepler photometry and has very large
transit timing variations (TTVs). Nesvorny+, performed a dynamical
analysis of the TTVs to uniquely identify the orbital period and mass
of the perturbing planet (Kepler-88c), which was later was confirmed
with RVs from the Observatoire de Haute-Provence (OHP). To fully
explore the architecture of this system, we performed photodynamical
modeling on the Kepler photometry combined with the RVs from Keck and
OHP and stellar parameters from spectroscopy and Gaia. Planet d is not
detectable in the photometry, and long-baseline RVs are needed to
ascertain its presence. A photodynamical model simultaneously
optimized to fit the RVs and Kepler photometry yields the most precise
planet masses and orbital properties yet for b and c:
Pb=10.91647±0.00014days, Mb=9.5±1.2M⊕,
Pc=22.2649±0.0007days, and Mc=214.0±5.3M⊕_. The
photodynamical solution also finds that planets b and c have low
eccentricites and low mutual inclination, are apsidally anti-aligned,
and have conjunctions on the same hemisphere of the star. Continued RV
follow-up of systems with small planets will improve our understanding
of the link between inner planetary system architectures and giant
planets.
Description:
We obtained 44 Radial Velocities (RVs) of Kepler-88 on the High
Resolution Echelle Spectrometer (HIRES) spectrograph at the W.M.Keck
Observatory between the years 2013 and 2020. We used the standard
HIRES setup of the California Planet Search. We used the C2 decker
(0.86"x14", R=60000) to enable sky-subtraction for this relatively
faint (V=13.8) target. Since the target was faint, we only observed in
good conditions (seeing <1.5", clear to thin clouds). For each
spectrum, we achieved a signal-to-noise ratio of at least 50 to ensure
that our Doppler pipeline would deliver RVs with errors of <10m/s.
Barros+, (2014A&A...561L...1B 2014A&A...561L...1B) used the Observatoire de Haute-Provence
(OHP) telescope and SOPHIE high-resolution echelle spectrograph to
measure RVs of the Kepler-88 system.
Objects:
----------------------------------------------------------------
RA (2000) DE Designation(s) (Period)
----------------------------------------------------------------
19 24 35.54 +40 40 09.8 Kepler-88 = KOI-142
19 24 35.54 +40 40 09.8 Kepler-88b = KOI-142.01 (P=10.95)
----------------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 36 55 Kepler-88 RVs
table6.dat 48 452 Kepler-88b transit times and velocities
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/A+A/363/1081 : Non-linear limb-darkening law for LTE models (Claret 2000)
J/A+A/414/351 : ELODIE survey northern extrasolar planets III (Naef+, 2004)
J/ApJ/622/1102 : The planet-metallicity correlation. (Fischer+, 2005)
J/ApJ/693/1084 : Ten new and updated multiplanet systems (Wright+, 2009)
J/ApJS/197/2 : Transit timing observations from Kepler. I. (Ford+, 2011)
J/ApJS/197/8 : Kepler's candidate transiting planets (Lissauer+, 2011)
J/ApJ/750/113 : Kepler TTVs. II. Confirmed multiplanet systems (Ford+, 2012)
J/ApJ/759/19 : Precise radial velocities of ρ1 Cancri (Endl+, 2012)
J/MNRAS/421/2342 : 4 Kepler systems transit timing observations (Steffen+,2012)
J/ApJS/208/16 : Kepler transit timing observations. VIII. (Mazeh+, 2013)
J/ApJ/790/146 : Planets Kepler's multi-transiting systems (Fabrycky+, 2014)
J/ApJS/210/20 : Small Kepler planets radial velocities (Marcy+, 2014)
J/ApJ/784/45 : Kepler's multiple planet candidates. III. (Rowe+, 2014)
J/ApJ/787/47 : 106 Kepler ultra-short-period planets (Sanchis-Ojeda+, 2014)
J/ApJ/821/89 : 12yrs of RVs obs. of exoplanet systems (Bryan+, 2016)
J/ApJS/225/9 : Kepler TTVs. IX. The long-cadence data set (Holczer+, 2016)
J/A+A/586/A93 : WASP41 and WASP47 photo. and RV data (Neveu-VanMalle+, 2016)
J/AJ/154/237 : HARPS-N radial velocities of WASP-47 (Vanderburg+, 2017)
J/A+A/615/A90 : Kepler-419 radial velocities (Almenara+, 2018)
J/AJ/156/264 : California-Kepler Survey VII. Planet rad. gap (Fulton+,2018)
J/AJ/157/52 : Radial velocity obs. in super-Earth systems (Bryan+, 2019)
J/AJ/157/235 : Observations of the Kepler field with TESS (Christ+, 2019)
J/AJ/157/145 : HIRES RVs of 3 compact, multiplanet systems (Mills+, 2019)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 F11.6 d BJD [1575/4014] Barycentric Julian Date BJD-2454900
13- 17 F5.1 m/s RV [-86.7/80.2] Radial velocity (1)
19- 22 F4.1 m/s e_RV [2.1/16.0] Uncertainty in RV (2)
24- 29 F6.4 --- SHK [0.1178/0.208]? The Mt. Wilson SHK value
31- 36 A6 --- Inst Instrument; HIRES or SOPHIE
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Note (1): SOPHIE RVs are from Barros+, 2014A&A...561L...1B 2014A&A...561L...1B.
The SOPHIE RVs have had 20465.0m/s added, with respect to the values
published in Barros+, 2014A&A...561L...1B 2014A&A...561L...1B for easier zero-point
calibration.
HIRES RVs are from this work.
Note (2): Does not include RV jitter.
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Epoch [0/451] Epoch number
5- 13 F9.4 --- T0 [55.08/4996] Transit midepoint time; BJD-2454900
15- 20 F6.4 --- e_T0 [0.0002/0.0344] Uncertainty in T0
22- 27 F6.4 AU b [0.0016/0.0031] Impact parameter
29- 34 F6.4 AU e_b [0.0001/0.0002] Uncertainty in b
36- 41 F6.4 AU/d Vel [0.0507/0.0578] Planet velocity
43- 48 F6.4 AU/d e_Vel [0.0004/0.0005] Uncertainty in Vel
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS] 17-Jun-2020