J/ApJ/807/170 Prograde vs retrogade motions. II. KOIs (Holczer+, 2015)
Time variation of Kepler transits induced by stellar spots
--A way to distinguish between prograde and retrograde motion.
II. Application to KOIs.
Holczer T., Shporer A., Mazeh T., Fabrycky D., Nachmani G., McQuillan A.,
Sanchis-Ojeda R., Orosz J.A., Welsh W.F., Ford E.B., Jontof-Hutter D.
<Astrophys. J., 807, 170 (2015)>
=2015ApJ...807..170H 2015ApJ...807..170H (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Planets ; Photometry
Keywords: planetary systems; stars: activity; stars: rotation;
techniques: photometric
Abstract:
Mazeh et al. (Paper I: 2015ApJ...800..142M 2015ApJ...800..142M) have presented an approach
that can, in principle, use the derived transit timing variation (TTV)
of some transiting planets observed by the Kepler mission to
distinguish between the prograde and retrograde motion of their orbits
with respect to their parent stars' rotation. The approach utilizes
TTVs induced by spot-crossing events that occur when the planet moves
across a spot on the stellar surface, looking for a correlation
between the derived TTVs and the stellar brightness derivatives at the
corresponding transits. This can work even in data that cannot
temporally resolve the spot-crossing events themselves. Here, we apply
this approach to the Kepler KOIs, identifying nine systems where the
photometric spot modulation is large enough and the transit timing
accurate enough to allow detection of a TTV-brightness-derivatives
correlation. Of those systems, five show highly significant prograde
motion (Kepler-17b, Kepler-71b, KOI-883.01, KOI-895.01, and
KOI-1074.01), while no system displays retrograde motion, consistent
with the suggestion that planets orbiting cool stars have prograde
motion. All five systems have impact parameter 0.2≲b≲0.5, and all
systems within that impact parameter range show significant
correlation, except HAT-P-11b where the lack of a correlation follows
its large stellar obliquity. Our search suffers from an observational
bias against detection of high impact parameter cases, and the
detected sample is extremely small. Nevertheless, our findings may
suggest that stellar spots, or at least the larger ones, tend to be
located at low stellar latitude, but not along the stellar equator,
similar to the Sun.
Description:
We used the transit timing catalog obtained by T. Holczer et al.
(2015, in preparation) publicly available at:
ftp://wise-ftp.tau.ac.il/pub/tauttv/TTV/ver_112
2600 KOIs where selected from the NASA Exoplanet Archive.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 46 224133 Light curve local slope for KOI transits
table2.dat 93 2600 Statistical parameters of the transit timing
variations (TTVs) and the stellar rotation
of the KOIs
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/ApJ/801/3 : Rotation periods for Q3-Q14 KOIs (Mazeh+, 2015)
J/ApJ/784/45 : Kepler's multiple planet candidates. III. (Rowe+, 2014)
J/ApJS/211/24 : Rotation periods of Kepler MS stars (McQuillan+, 2014)
J/ApJS/210/25 : TTVs for 15 planetary pairs. II. (Xie, 2014)
J/ApJS/208/16 : Kepler transit timing observations. VIII. (Mazeh+, 2013)
J/ApJ/775/L11 : Stellar rotation periods for KOIs (McQuillan+, 2013)
J/other/Sci/337.1511 : Kepler-47 transits (Orosz+, 2012)
J/ApJ/757/18 : RVs for 16 hot Jupiter host stars (Albrecht+, 2012)
J/ApJ/750/114 : Kepler TTVs. IV. 4 multiple-planet systems (Fabrycky+, 2012)
J/ApJ/750/113 : Kepler TTVs. II. Confirmed multiplanet systems (Ford+, 2012)
J/ApJ/749/15 : The Kepler-20 planetary system (Gautier+, 2012)
J/MNRAS/421/2342 : 4 Kepler systems transit timing obs. (Steffen+, 2012)
J/ApJS/197/2 : Transit timing observations from Kepler. I. (Ford+, 2011)
J/ApJ/733/127 : Four transits of WASP-4b (Sanchis-Ojeda+, 2011)
J/AJ/142/160 : Kepler Mission. II. 2165 eclipsing binaries (Slawson+, 2011)
J/AJ/141/83 : Eclipsing binaries in Kepler first data release (Prsa+, 2011)
J/A+A/527/L11 : HAT-P-6 radial velocity curve (Hebrard+, 2011)
J/A+A/524/A25 : Radial Velocities on 6 exoplanet host stars (Triaud+, 2010)
J/ApJ/723/L223 : Radial velocities of HAT-P-11 (Winn+, 2010)
http://exoplanetarchive.ipac.caltech.edu/ : NASA exoplanet archive
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 F7.2 --- KOI [1.01/5970.01] Planet KOI number (NNNN.NN)
9- 12 I4 --- n [0/2503] Transit number
14- 24 F11.6 d tt Expected mid transit time of the linear ephemeris
(BJD-2454900) (1)
26- 34 F9.1 ppm/d s [-266900/297600] Derived local slope,
parts per million per day
36- 42 F7.1 ppm/d e_s [3/30000] Uncertainty in derived local slope, s
44 I1 --- deg [1/6] Polynomial degree, fitted
46 I1 --- flag [0/1] 0 = ok, 1 = identified as an outlier
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Note (1): Following Holczer et al. (2015, in preparation)
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 F7.2 --- KOI [1.01/5970.01] Planet candidate KOI number (NNNN.NN)
9- 17 F9.5 d Porb [0.5/298.5] Orbital period
19- 23 I5 --- Depth [27/97317] Transit depth in parts per million
25- 29 F5.2 d Prot [0.8/50]? Rotational period
31- 35 I5 ppm Arot [0/32015]? Rotational semi amplitude,
parts per million (1)
37 I1 --- flag [0/2]? Rotational Flag (2)
39- 49 F11.2 min/d gS ? Global slope
51- 60 F10.2 min/d e_gS [0.5/1500000]? Global slope uncertainty
64 A1 --- f_(p-S) Upper limit Flag on (p-S)
66- 69 F4.1 [-] (p-S) [-7/-0]? log of the p-value of the (gS/e_gS) ratio
71- 75 F5.2 min TTV [0/15.8]? Maximum expected TTV due to spot crossing
77- 82 F6.2 min e_TTV [0.06/292.1] Median of TTV uncertainties
84- 87 I4 --- N [1/1502] Number of transit time measurements
89- 93 F5.1 --- TTVs [0/292.1]? TTV sensitivity
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Note (1): Rotational semi amplitude derivation from McQuillan, Mazeh, and
Aigrain (2013ApJ...775L..11M 2013ApJ...775L..11M, 2014ApJS..211...24M 2014ApJS..211...24M).
Note (2): Rotation Flag, based on the findings of McQuillan, Mazeh, and Aigrain
(2013ApJ...775L..11M 2013ApJ...775L..11M, 2014ApJS..211...24M 2014ApJS..211...24M) as follows:
0 = KOI was analyzed and no period was identified,
1 = A rotation period was detected,
2 = KOI was not analyzed.
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History:
From electronic version of the journal
References:
Mazeh et al. Paper I. 2015ApJ...800..142M 2015ApJ...800..142M
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 22-Oct-2015