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Properties of Hot, Giant Planet Planets Orbiting Evolved Stars

Properties of Hot, Giant Planet Planets Orbiting Evolved Stars

Seminar at the University of Tokyo Department of Astronomy

skgrunblatt

March 30, 2018
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  1. Properties of Hot, Giant Planets Orbiting Low Luminosity Red Giant

    Branch (LLRGB) Stars Samuel Grunblatt, Daniel Huber, Eric Gaidos, Eric Lopez, Filipe Pereira, Tiago Campante Institute for Astronomy, University of Hawaii— Manoa, Honolulu, HI, USA
  2. Stellar activity: 10-30 m/s Planetary signal: 1.5 m/s HARPS-N HIRES

    My experience: Gaussian process RV analysis Grunblatt et al. (2015)
  3. K2: Extension to the NASA Kepler Mission high precision photometry

    from space (~30-100 ppm precision) 80 day observing campaigns, 30 minute cadence community chosen targets
  4. A SEARCH FOR GIANTS ORBITING GIANTS WITH K2 ➤ 10,000

    targets in C1-10 ➤ K2 limit for asteroseismology: 283 μHz (~3 Rsun) ➤ Transit detection limit: ~10 Rsun ➤ Temperature limits: 4500—5500 K 
 (avoids horizontal branch stars) Huber et al. (2016)
  5. Seeing Double with K2: Two Remarkably Similar Planets Orbiting Red

    Giant Branch Stars Grunblatt et al. (2017)
  6. Grunblatt et al. (2017) Seeing Double with K2:… Rs =

    3.85 +/- 0.13 R⊙ Ms = 1.08 +/- 0.08 M⊙ Rs = 4.20 +/- 0.14 R⊙ Ms = 1.16 +/- 0.12 M⊙
  7. Gaussian process lightcurve fitting Used squared exponential and simple harmonic

    oscillator GP kernel functions to account for granulation & oscillation noise no GP
  8. Gaussian process lightcurve fitting Used squared exponential and simple harmonic

    oscillator GP kernel functions to account for granulation noise SE GP
  9. Gaussian process lightcurve fitting Used squared exponential and simple harmonic

    oscillator GP kernel functions to account for granulation noise SHO GP
  10. Combined transit + GP models Used squared exponential and simple

    harmonic oscillator GP kernel functions to account for astrophysical noise Grunblatt et al. (2017) Simple Harmonic Oscillator GP Squared Exponential GP
  11. SHO model tells us about star, too Simple harmonic oscillator

    GP model traces stellar granulation & oscillation signals: estimate of νmax from time-domain! Grunblatt et al. (2017) νmax, pipeline = 245.65 ± 3.51 μHz νmax, GP = 239.4 ± 1.8 μHz
  12. SHO model tells us about star, too Simple harmonic oscillator

    GP model traces stellar granulation & oscillation signals: estimate of νmax from time-domain! Grunblatt et al. (in prep.) νmax, pipeline = 245.65 ± 3.51 μHz νmax, GP = 239.4 ± 1.8 μHz
  13. Grunblatt et al. (2017) Seeing Double with K2:… Rs =

    3.85 +/- 0.13 R⊙ Ms = 1.08 +/- 0.08 M⊙ Rp = 1.30 +/- 0.07 RJ Rs = 4.20 +/- 0.14 R⊙ Ms = 1.16 +/- 0.12 M⊙ Rp = 1.31 +/- 0.11 RJ
  14. Charbonneau et al. (2000) “The derived value of Rp =

    1.27 +/- 0.02 RJup is in excellent agreement with the early predictions of Guillot et al. (1996), who calculated the radius for a strongly irradiated radiative/convective extrasolar planet for a variety of masses.”
  15. Lopez & Fortney (2016) maximum expected radius highly inflated not

    inflated Inflated Hot Jupiters are ubiquitous.
  16. The Mechanism of Planet Inflation e.g., Bodenheimer+ (2001), Showman &

    Guillot (2002),
 Batygin & Stevenson (2010), Ginzburg & Sari (2016) Class I: planet interior inflated directly by increased stellar irradiation Class II: cooling delayed after planet formation e.g., Burrows+ (2000), Chabrier & Baraffe (2007), Leconte & Chabrier (2012), Wu & Lithwick (2013)
  17. How to distinguish between Classes I and II? Class I:

    re-inflation Class II: no re-inflation
  18. Are they re-inflated? Grunblatt et al. (2017) avg incident flux

    on main sequence: K2-97b: 
 170 +140-60 F EPIC2287b: 190 +150-80 F
  19. typical incident flux range for 1.3 RJ planets current incident

    flux: K2-97b: 
 900 +200-150 F EPIC2287b: 850 +250-140 F current incident fluxes Grunblatt et al. (2017) Are they re-inflated?
  20. Need to delay cooling by different rates in every case

    to explain observed planet radii. ] Grunblatt et al. (2017) different delayed cooling models Are they re-inflated?
  21. Data implies significant post-MS planet heating. But how? delayed cooling

    ] re-inflation Grunblatt et al. (2017) Are they re-inflated? Probably.
  22. Grunblatt et al. (2017) Seeing Double with K2:… Mp =

    0.48 +/- 0.07 MJ Mp = 0.49 +/- 0.06 MJ
  23. Seeing Double with K2:… they might be eccentric! Implications for

    re-inflation? Implications for re-inflation?
  24. How to calculate occurrence: pj = a/R*, n*,j = number

    of stars searched where SNR(transit) > some threshold (determined by injection/recovery here) Made grid of periods and planet radii, and for each grid cell, calculated whether SNR > SNRthreshold for every star in our sample to find n* Howard et al. (2012)
  25. Completeness in our sample: almost all inflated Jupiters, ~60% of

    Jupiter-sized planets, Neptunes in best cases
  26. Summary Combining asteroseismology and transit analysis with a Gaussian process

    framework provides uniquely well- characterized exoplanet systems. Among ~4500 LLRGB stars, 2 (remarkably similar) close- in, transiting, likely re-inflated giant planets found: related to eccentricity? indicative of unique evolutionary pathway among evolved stars? Planet occurrence of LLRGB stars roughly comparable to MS, but effects of evolution could be appearing…TESS is the answer!
  27. Appendix. Why are K2-97b, K2-132b so similar? 0.01 0.10 1.00

    10.00 planet mass (Jupiters) 0.0 0.2 0.4 0.6 0.8 1.0 survey bias factor Short answer: probably survey bias * intrinsic planet occurrence
  28. Appendix. Why is planet transit depth poorly constrained? Different lightcurves

    treat systematics differently. Somewhat accounted for with GP model Grunblatt et al. (2016)
  29. Asteroseismic stellar parameters: are they accurate? Next project: calibrate asteroseismic

    relations with interferometry, bolometric fluxes from spectra, and Gaia parallaxes ~300 spectra in hand now (~500 wanted!)