Properties of Close-In Giant Planets Orbiting Evolved Stars

An exploration of the occurrence of planets orbiting stars 3-8 times the size of the Sun, as measured by the NASA Kepler telescope.

Transcript

1. Properties of Close-In Giant Planets Orbiting Evolved Stars Samuel Grunblatt, Daniel Huber, Eric Gaidos, Eric Lopez, Vincent Van Eylen, Thomas Barclay, Ashley Chontos, Evan Sinukoff, Andrew Howard, Howard Isaacson TASC IV-Aarhus, Denmark July 10, 2018
2. Known planets around red giant stars (2015) RV transit
3. Known planets around red giant stars (2018) K2-97b K2-132b K2-99b K2-39b Kepler-435b RV transit
4. Known planets around red giant stars (2018) K2-97b K2-132b K2-99b K2-39b Kepler-435b “A Search for Giants Orbiting Giants With K2”
5. Asteroseismic stellar parameters:
6. Asteroseismic stellar parameters: 1676 LL giants, σM < 10%, σR < 5% low-luminosity giants
7. 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 +/- 0.11 M⊙
8. 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
9. Where did the inflated Jupiters come from? How did the inflated Jupiters get there?
10. Where did the inflated Jupiters come from? How did the inflated Jupiters get there?
11. Rp increases as star evolves. Grunblatt et al. (2017) Seeing Double with K2:…
12. Rp increases as star evolves. Grunblatt et al. (2017) Seeing Double with K2:…
14. What about orbital parameters?
15. They’re eccentric! (e~0.3) Grunblatt et al. (2018)
16. Grunblatt et al. (2018) They’re eccentric! (e~0.3)
17. Do close-in giant planets orbiting evolved stars prefer eccentric orbits? Grunblatt et al. (2018)
18. Do close-in giant planets orbiting evolved stars prefer eccentric orbits? Grunblatt et al. (2018)
19. Do close-in giant planets orbiting evolved stars prefer eccentric orbits? Grunblatt et al. (2018) e = 0.15 +0.08-0.04
20. Do close-in giant planets orbiting evolved stars prefer eccentric orbits? Grunblatt et al. (2018) e = 0.06 +0.02-0.01 e = 0.15 +0.08-0.04
21. Do close-in giant planets orbiting evolved stars prefer eccentric orbits? Grunblatt et al. (2018)
22. Do close-in giant planets orbiting evolved stars prefer eccentric orbits? Grunblatt et al. (2018)
23. Do close-in giant planets orbiting evolved stars prefer eccentric orbits? Grunblatt et al. (2018)
24. Do close-in giant planets orbiting evolved stars prefer eccentric orbits? Check out AAS Nova and UHIfA Aloha Briefs on Youtube to learn more! arXiv:1805.11620 ApJL, 861, L5
25. How did the inflated Jupiters get there? A combination of tidal heating/migration and increasing stellar irradiation. (Grunblatt+2016,2017,2018) Where did the inflated Jupiters come from?
26. Where did the inflated Jupiters come from? How did the inflated Jupiters get there? A combination of tidal heating/migration and increasing stellar irradiation. (Grunblatt+2016,2017,2018)
27. LLRGB Planet Occurrence Grunblatt (2018b, in prep.)
28. LLRGB Planet Occurrence Grunblatt (2018b, in prep.) planet occurrence decreases with radius around MS stars…
29. LLRGB Planet Occurrence Grunblatt (2018b, in prep.) …but seems to increase with radius around evolved stars! planet occurrence decreases with radius around MS stars…
30. LLRGB Planet Occurrence Grunblatt (2018b, in prep.)
31. LLRGB Planet Occurrence Grunblatt (2018b, in prep.) re-inflation by irradiation
32. LLRGB Planet Occurrence Grunblatt (2018b, in prep.) re-inflation by tidal migration
33. Grunblatt (2018b, in prep.) K2 Survey Completeness
34. Better statistics with TESS! more stars=more complete for short period, small planets
35. Better statistics with TESS! longer baselines=more complete for longer period planets
36. How did the inflated Jupiters get there? Re-inflation, through a combination of tidal heating and increasing stellar irradiation. Where did the inflated Jupiters come from? TESS will tell us.
37. Summary Stellar evolution causes orbital migration and inflates close-in giant planets at late times. (Grunblatt+2016,2017,2018, arXiv:1805.11620, watch the brief @ www.youtube.com/UHIfA) Because of this, unlike main sequence systems planet occurrence increases with Rp for close-in giant planets orbiting evolved stars. (Grunblatt+2018b, in prep.) Where did these late-stage inflated Jupiters come from? TESS to the rescue!
38. EXTRA SLIDES
39. 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
40. Villaver et al. (2014) Do close-in giant planets orbiting evolved stars prefer eccentric orbits?
41. Seeing Double with K2:… they might be eccentric!
42. Seeing Double with K2:… they might be eccentric!
43. Seeing Double with K2:… they might be eccentric!
44. How to calculate occurrence: 1/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 scenario, calculated whether SNR > SNRthreshold for every star in our sample to find n*,j Howard et al. (2012)
45. Injection/Recovery Grunblatt (2018b, in prep.)
46. Grunblatt (2018b, in prep.) K2 Survey Completeness
47. LLRGB Planet Occurrence Grunblatt (2018b, in prep.)
48. Injection/Recovery Grunblatt (2018b, in prep.)
49. LLRGB Planet Occurrence Grunblatt (2018b, in prep.)
50. LLRGB Planet Occurrence Grunblatt (2018b, in prep.) 0.23%
51. LLRGB Planet Occurrence Grunblatt (2018b, in prep.) 0.23% 0.06%
52. LLRGB Planet Occurrence Grunblatt (2018b, in prep.)
53. Tidal inflation: the great unknown Potentially consistent with observations, but need better constraints of Qp and Q* (currently uncertain by 2 orders of magnitude, and potentially variable over time) Goldreich+66, Hut81, Dobbs-Dixon+04, Miller+09, Gallet+17, Fuller17… Very strongly dependent on stellar radius (δe, δa ~ R*8!) Could act together with increased irradiational heating due to stellar evolution Both mechanisms less effective for larger Qp