J/ApJ/770/36 APOSTLE transits of XO-2 system (Kundurthy+, 2013)
APOSTLE: longterm transit monitoring and stability analysis of XO-2b.
Kundurthy P., Barnes R., Becker A.C., Agol E., Williams B.F., Gorelick N.,
Rose A.
<Astrophys. J., 770, 36 (2013)>
=2013ApJ...770...36K 2013ApJ...770...36K
ADC_Keywords: Stars, double and multiple ; Planets ; Photometry, RI
Keywords: eclipses; methods: numerical; planetary systems;
planets and satellites: fundamental parameters;
planets and satellites: individual: XO-2b
Abstract:
The Apache Point Survey of Transit Lightcurves of Exoplanets (APOSTLE)
observed 10 transits of XO-2b over a period of 3yr. We present
measurements that confirm previous estimates of system parameters like
the normalized semi-major axis (a/R*), stellar density (ρ*),
impact parameter (b), and orbital inclination (iorb). Our errors on
system parameters like a/R* and ρ* have improved by ∼40%
compared to previous best ground-based measurements. Our study of the
transit times show no evidence for transit timing variations (TTVs)
and we are able to rule out co-planar companions with masses
≥0.20M⊕ in low order mean motion resonance with XO-2b. We
also explored the stability of the XO-2 system given various orbital
configurations of a hypothetical planet near the 2:1 mean motion
resonance. We find that a wide range of orbits (including Earth-mass
perturbers) are both dynamically stable and produce observable TTVs.
We find that up to 51% of our stable simulations show TTVs that are
smaller than the typical transit timing errors (∼20s) measured for
XO-2b, and hence remain undetectable.
Description:
XO-2b was observed by members of the APOSTLE team on 10 occasions over
a timespan of 3yr from early 2008 until the spring of 2011. All
observations of XO-2 were carried out using AGILE, a high-speed
frame-transfer CCD, on the ARC 3.5m telescope at Apache Point, New
Mexico. Early observations were made in the I-band (λ0=805nm).
Early in 2010, the observing strategy changed to longer readouts
(typically 45-75s) to reduce the level of correlated noise
(red-noise), and were made using the r'-band which is similar to the
SDSS r filter (λ0=626nm).
Objects:
---------------------------------------------------------------
RA (ICRS) DE Designation(s) (Period)
---------------------------------------------------------------
07 48 06.47 +50 13 33.0 XO-2 = TYC 3413-5-1 (P=2.615860)
---------------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 49 3326 APOSTLE lightcurve data for XO-2
table10.dat 85 3600000 Data on the stability simulations of the XO-2 system
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See also:
J/A+A/552/A119 : Planet-star and moon-planet interaction (Saur+, 2013)
J/ApJ/764/8 : APOSTLE transit lightcurves of TrES-3b (Kundurthy+, 2013)
J/ApJ/757/161 : Spectroscopy of 56 exoplanet host stars (Torres+, 2012)
J/MNRAS/426/1291 : Physical properties of 38 exoplanets (Southworth, 2012)
J/MNRAS/422/2024 : X-ray-age relation & exoplanet evaporation (Jackson+, 2012)
J/A+A/529/A75 : Limb-darkening coefficients (Claret+, 2011)
J/PASP/123/412 : Exoplanet Orbit Database (Wright+, 2011)
J/MNRAS/414/1278 : Eccentricities of transiting planets (Pont+, 2011)
J/MNRAS/411/L46 : Exoplanet magnetic fields (Vidotto+, 2011)
J/ApJ/731/123 : APOSTLE light curve of GJ 1214b (Kundurthy+, 2011)
J/ApJ/716/1336 : Stability analysis of single-planet (Kopparapu+, 2010)
J/AJ/137/4911 : Six transits of the exoplanet XO-2b (Fernandez+, 2009)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- TNum [1/10] Transit Number
4- 13 F10.7 d T-T0 [-0.16/0.14] Time - Mid Transit Time; BJD (1)
15- 25 F11.9 --- NFlux [0.98/1.01] Normalized flux ratio
27- 37 F11.9 --- e_NFlux Error in NFlux
39- 49 F11.9 --- MFlux [0.98/1] Transit Model
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Note (1): To get time stamps, add mid transit times from table with TMCMC
(Transit Markov Chain Monte Carlo analyzer, see section 3.3) fits
from the section on Transit Timing Variations.
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Byte-by-byte Description of file: table10.dat
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Bytes Format Units Label Explanations
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1- 7 I7 --- SimID [0/3599999] Simulation identifier (1)
9- 12 F4.1 Mgeo Mp Mass of perturber; Earth masses (2)
14- 19 F6.4 AU a Semi-major axis (2)
21- 23 F3.1 --- e Eccentricity (2)
25- 26 I2 deg i Orbital inclination (2)
28- 32 F5.1 deg Omega Argument of pericenter (2)
34- 36 I3 deg omega Longitude of ascending node (2)
38- 40 I3 deg M Mean anomaly (2)
42 I1 --- Stab [0/1] Stability outcome (1=stable) (3)
44- 52 E9.4 --- ECons [0/2.7] Energy conservation (3)
54- 63 E10.4 s stdTTV [0/370800]?=-1 Standard deviation of transit
timing variations (3)
65- 74 E10.4 --- stdTDV [0/0.01]?=-1 Standard deviation of transit
depth variations (3)
76- 85 E10.4 --- stdTBV [0/0.07]?=-1 Standard deviation of transit
impact parameter (b) variations (3)
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Note (1): This Machine readable table contains data from 3.6 Million
simulations of the XO-2 system. The set of initial configurations
are noted in Table 9:
------------------------------------------------
Param Unit Min Max Delta N
------------------------------------------------
Mass M⊕ 1 10 1 10
a AU 0.055 0.062 0.0016 5
e --- 0 0.8 0.1 9
iorb ° 0.001 70 10 8
Ω ° 0 324 36 10
ω ° 0 324 36 10
M ° 0 324 36 10
------------------------------------------------
Note (2): These columns note the configuration of a given Simulation ID number.
Also see the section on dynamics in the paper.
Note (3): These columns are properties from a given Simulation. Where stability
of 1 or 0 indicates whether the simulation was stable or unstable
respectively. ECons documents the maximum relative change in
energy between a step (dE/E), in the simulation.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 08-Jan-2015