J/AJ/155/255 Radial velocity and activity measurements of HAT-P-11 (Yee+, 2018)
HAT-P-11: discovery of a second planet and a clue to understanding exoplanet
obliquities.
Yee S.W., Petigura E.A., Fulton B.J., Knutson H.A., Batygin K., Bakos G.A.,
Hartman J.D., Hirsch L.A., Howard A.W., Isaacson H., Kosiarek M.R.,
Sinukoff E., Weiss L.M.
<Astron. J., 155, 255 (2018)>
=2018AJ....155..255Y 2018AJ....155..255Y (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing ; Stars, dwarfs ; Stars, K-type ;
Radial velocities ; Spectroscopy ; Exoplanets
Keywords: planetary systems - planets and satellites: detection -
planets and satellites: dynamical evolution and stability -
stars: individual (HAT-P-11)
Abstract:
HAT-P-11 is a mid-K dwarf that hosts one of the first Neptune-sized planets
found outside the solar system. The orbit of HAT-P-11b is misaligned with
the star's spin-one of the few known cases of a misaligned planet orbiting
a star less massive than the Sun. We find an additional planet in the
system based on a decade of precision radial velocity (RV) measurements
from Keck/High Resolution Echelle Spectrometer. HAT-P-11c is similar
to Jupiter in its mass (MPsin i=1.6±0.1 MJ) and orbital period
(P=9.3-0.5+1.0 year), but has a much more eccentric orbit
(e=0.60±0.03). In our joint modeling of RV and stellar activity, we found
an activity-induced RV signal of ∼7 m/s, consistent with other active
K dwarfs, but significantly smaller than the 31 m/s reflex motion due to
HAT-P-11c. We investigated the dynamical coupling between HAT-P-11b and c
as a possible explanation for HAT-P-11b's misaligned orbit, finding that
planet-planet Kozai interactions cannot tilt planet b's orbit due to
general relativistic precession; however, nodal precession operating
on million year timescales is a viable mechanism to explain HAT-P-11b's
high obliquity. This leaves open the question of why HAT-P-11c may have
such a tilted orbit. At a distance of 38 pc, the HAT-P-11 system offers
rich opportunities for further exoplanet characterization through
astrometry and direct imaging.
Description:
The California Planet Search (CPS; Howard et al. 2010ApJ...721.1467H 2010ApJ...721.1467H)
has observed the HAT-P-11 system since 2007 August with the High
Resolution Echelle Spectrometer (HIRES; Vogt et al. 1994SPIE.2198..362V 1994SPIE.2198..362V)
at the Keck I 10 m telescope on Maunakea. We collected a total of 253
spectra with an iodine cell in front of the spectrometer, which imprints
iodine absorption lines to serve as a wavelength reference against
which RVs can be measured precisely. The spectra have signal-to-noise
ratios between 100 and 130 per pixel on blaze near 5500 Å.
Objects:
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RA (ICRS) DE Designation(s)
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19 50 50.25 +48 04 51.1 HAT-P-11 = BD+47 2936
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 58 253 Radial velocity and activity measurements
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See also:
J/ApJ/710/1724 : Follow-up photometry for HAT-P-11 (Bakos+, 2010)
J/ApJ/723/L223 : Radial velocities of HAT-P-11 (Winn+, 2010)
J/ApJ/785/126 : HIRES radial velocity measurements (Knutson+, 2014)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 14 F14.6 d BJD Barycentric Julian Date; TDB
16- 21 F6.2 m/s RV [-57.41/22.81] Barycentric radial velocity (1)
23- 26 F4.2 m/s e_RV [0.92/2.97] Uncertainty in RV (1)
28- 33 F6.4 --- SHK [0.454/0.6502] The SHK index (1)
35- 40 F6.4 --- e_SHK [0.0045/0.0065] Uncertainty in SHK (1)
42- 48 F7.5 --- HaInd [0.04458/0.04668] The Hα index (1)
50- 56 F7.5 --- e_HaInd [0.0002/0.00035] Uncertainty in HaInd (1)
58 I1 --- Flag [0/1]? Data flag (2)
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Note (1): Radial velocities and activity measurements calculated from HIRES
observations.
Note (2): Flag as follows:
1 = The data point was used in our analysis;
0 = The data point was not used in our analysis.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 07-Jan-2019