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MethodsSpace photometry / transit modellingDip-shape model comparison and asymmetry statistic
Method · space photometry / transit modelling

Dip-shape model comparison and asymmetry statistic

Ask whether a dip's shape is that of a hard body crossing a limb-darkened disc or of a diffuse cloud, independently of colour information, and place it among the Kepler dips.

Space photometry / transit modellingVersion 1.0Licence MIT1 runUsed on 1 mystery

Questions it answers

Code Python

Download module (.py)dip_shape.pyView source

Runs and results 1 run

RunMysteryMeasuredResultAgainstDate
RUN0DEC25RSHDJ9Tabby'sBIC per model; derived transit parameters; ingress/egress ratio and deficit fraction before minimum per dip{'dBIC': {'planet': 0, 'gaussian': 195.8, 'skewgauss': 201, 'trapezoid': 26.8}, 'planet': {'b': 0.79, 'a_rs': 296, 'rp_rs': 0.11, 't0_BTJD': 1730.156, 'depth_pct': 1.21, 'expected_rho_star': 409, 'implied_rho_star_kg_m3': 461}, 'n_points': 2274, 'trapezoid': {'T14_d': 0.856, 'egress_d': 0.29, 'depth_pct': 1.17, 'ingress_d': 0.186}, 'planet_chi2': 2365, 'skewgauss_asymmetry': 0.89, 'asymmetry_2019_binned': {'A': 1.29, 'depth_pct': 1.25, 'deficit_before': 0.59}, 'asymmetry_kepler_deep': {'D140': [0.75, 0.44], 'D792': [0.77, 0.42], 'D1495': [0.6, 0.38], 'D1519': [0.65, 0.36], 'D1540': [0.57, 0.36], 'D1568': [0.6, 0.35]}}

Applied to

Tabby's star (KIC 8462852)
2 datasetsKepler long-cadence light curve of KIC 8462852, Quarters 0-17, as one CSV, TESS light curves of TIC 185336364 (KIC 8462852), Sectors 14-82, as flat CSV

References

  1. Boyajian, T., LaCourse, D., Rappaport, S. et al. 2016. Planet Hunters IX. KIC 8462852 – where's the flux?. Monthly Notices of the Royal Astronomical Society 457(4), 3988–4004.
  2. arXiv:2607.20643 (July 2026). Models the symmetric 1.1 per cent dip in TESS Sector 15 (September 2019) as a planetary transit and combines it with archival and new radial velocities: a 2.3-sigma companion of about 9 Jupiter masses and 1.7 Jupiter radii with a period of at least about 1030 days, in several allowed period windows. Independently recovered in this department's TESS search.
  3. arXiv:2610.34806 (October 2026). Fits the 2019 TESS transit with a 1.1 Jupiter-radius planet carrying a ring out to 3-4 planetary radii.
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