J/ApJ/801/3 Rotation periods for Q3-Q14 KOIs (Mazeh+, 2015)
Photometric amplitude distribution of stellar rotation of KOIs
-Indication for spin-orbit alignment of cool stars and high obliquity for
hot stars.
Mazeh T., Perets H.B., McQuillan A., Goldstein E.S.
<Astrophys. J., 801, 3 (2015)>
=2015ApJ...801....3M 2015ApJ...801....3M
ADC_Keywords: Stars, double and multiple ; Planets
Keywords: methods: observational; planet-star interactions; stars: rotation;
planets and satellites: dynamical evolution and stability;
Abstract:
The observed amplitude of the rotational photometric modulation of a
star with spots should depend on the inclination of its rotational
axis relative to our line of sight. Therefore, the distribution of
observed rotational amplitudes of a large sample of stars depends on
the distribution of their projected axes of rotation. Thus, comparison
of the stellar rotational amplitudes of the Kepler objects of interest
(KOIs) with those of Kepler single stars can provide a measure to
indirectly infer the properties of the spin-orbit obliquity of Kepler
planets. We apply this technique to the large samples of 993 KOIs and
33614 single Kepler stars in temperature range of 3500-6500K. We find
with high significance that the amplitudes of cool KOIs are larger, on
the order of 10%, than those of the single stars. In contrast, the
amplitudes of hot KOIs are systematically lower. After correcting for
an observational bias, we estimate that the amplitudes of the hot KOIs
are smaller than the single stars by about the same factor of 10%. The
border line between the relatively larger and smaller amplitudes,
relative to the amplitudes of the single stars, occurs at about 6000K.
Our results suggest that the cool stars have their planets aligned
with their stellar rotation, while the planets around hot stars have
large obliquities, consistent with the findings of Winn et al.
(2010ApJ...718L.145W 2010ApJ...718L.145W) and Albrecht et al. (2012, J/ApJ/757/18). We
show that the low obliquity of the planets around cool stars extends
up to at least 50 days, a feature that is not expected in the
framework of a model that assumes the low obliquity is due to
planet-star tidal realignment.
Description:
For this work we used the list of the KOIs and their parameters from
the NASA Exoplanet Archive (NEA; Akeson et al. 2013PASP..125..989A 2013PASP..125..989A)
of 2014 March 25.
To measure the rotational periods, we use the public release 14
quarter 3-14 (Q3-Q14; 2009 Sept to 2012) LCs, which were downloaded
from the Kepler mission archive. See section 3.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 80 3355 Stellar rotational periods for the KOIs
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/ApJS/211/24 : Rotation periods of Kepler MS stars (McQuillan+, 2014)
J/MNRAS/436/1883 : Properties of KOI host stars (Walkowicz+, 2013)
J/A+A/560/A4 : Rotation periods of active Kepler stars (Reinhold+, 2013)
J/ApJ/775/L11 : Stellar rotation periods for KOIs (McQuillan+, 2013)
J/A+A/557/L10 : Rotation periods of 12000 Kepler stars (Nielsen+, 2013)
J/MNRAS/432/1203 : Rotation periods of M-dwarf stars (McQuillan+, 2013)
J/ApJ/767/95 : Improved parameters of smallest KIC stars (Dressing+, 2013)
J/ApJS/204/24 : Kepler planetary candidates. III. (Batalha+, 2013)
J/ApJ/757/18 : RVs for 16 hot Jupiter host stars (Albrecht+, 2012)
J/MNRAS/423/2966 : Low-mass stars spectroscopy in NGC 2516 (Jackson+, 2012)
J/AJ/142/160 : Kepler Mission. II. 2165 eclipsing binaries (Slawson+, 2011)
J/AJ/142/112 : KIC photometric calibration (Brown+, 2011)
J/ApJ/733/127 : Four transits of WASP-4b (Sanchis-Ojeda+, 2011)
J/AJ/141/166 : HATNet variability survey of K and M dwarfs (Hartman+, 2011)
J/AJ/141/83 : Eclipsing binaries in Kepler DR1 (Prsa+, 2011)
J/A+A/527/L11 : HAT-P-6 radial velocity curve (Hebrard+, 2011)
J/AJ/141/63 : Relative RVs of HAT-P-4 and HAT-P-14 (Winn+, 2011)
J/A+A/524/A25 : Radial Velocities on 6 exoplanet host stars (Triaud+, 2010)
J/A+A/397/147 : Activity-rotation relationship in stars (Pizzolato+ 2003)
http://exoplanetarchive.ipac.caltech.edu/ : NASA Exoplanet Archive home page
http://archive.stsci.edu/kepler/ : Kepler mission archive home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- KOI [1/6249] Kepler Object of Interest identifier
6- 13 I8 --- KIC Kepler Input Catalog identifier (V/133)
15- 19 I5 K Teff [3089/10949]? KIC effective temperature (1)
21- 25 F5.3 [g/cm3] log(g) [0.03/6.1]? KIC log surface gravity (1)
27- 32 F6.2 d Prot [0.08/154]? Rotational period
34- 38 F5.2 d e_Prot [0/73]? The 1σ uncertainty in Prot
40- 44 I5 ppm Rvar [-9999/96819]? Amplitude of modulation
(-9999 if no reliable amplitude)
46- 53 F8.6 --- LPH [0.01/1.8]? The Local Peak Height value
of the autocorrelation function (ACF)
55- 62 F8.6 --- w [0/1]? Assigned weight (the w value); see text
64 I1 --- D [0/1] "1" if Dressing & Charbonneau 2013
(J/ApJ/767/95) parameters used (1)
66 I1 --- N [0/1] "1" if KIC values missing, so NASA
Exoplanet Archive (NEA) parameters used (1)
68 I1 --- C [0/1] "1" if Centroid motion shows transit and
rotational modulation on different stars
70 I1 --- G [0/1] "1" if star is likely a giant
72 I1 --- T [0/1] "1" if Teff outside 3500-6500K
74 I1 --- F [0/1] "1" if false positive (EB) identified
in this work
76 I1 --- R [0/1] "1" if rejected by visual examination stage
78 I1 --- M1 [0/1] "1" if inconsistent detection in different
quarters
80 I1 --- M2 [0/1] "1" if inconsistent detection with not
high enough peaks
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Note (1): Value from KIC (V/133), unless the column "D" or "N" is set.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 07-Jul-2015