Comparing asteroids, comets, moons & planets as WD pollution progenitors

Transcription

1 NASA/JPL-Caltech M. Kornmesser Comparing asteroids, comets, moons & planets as WD pollution progenitors Dimitri Veras (University of Warwick) ESO /

2 Start with observables Number of confirmed WD planets Mullally et al. (2008) Hogan et al. (2009) 0! Debes et al. (2011) Faedi et al. (2011) Steele et al. (2011) Number of WD dust discs Zuckerman & Becklin (1987); Becklin et al. (2005) 30 Kilic et al. (2005) Reach et al. (2005) Farihi et al. (2009) Number of WD gas discs! Gänsicke et al. (2006) Gänsicke et al. (2007) Gänsicke et al. (2008) 7 Debes et al. (2012) Brinkworth et al. (2012) Melis et al. (2012)

3 Location of WD discs See Debes talk on Wed! SUN (FOR SCALE) DISC WD VERY COMPACT!

4 Metal pollution in white dwarf atmospheres Widespread Diverse Sometimes Earth-like Sometimes water-rich Zuckerman et al. (2003, 2010), Koester et al. (2014) See Zuckerman talk on Fri! e.g. Gänsicke et al. (2012) See Gänsicke talk on Thurs! e.g. Klein et al. (2010) Farihi et al. (2013), See Raddi talk on Fri!

5 Goal: Reproduce Observables Accretion occurs early and late in DA WDs Koester, Gänsicke, Farihi (2014)

6 Goal: Reproduce Observables Accretion of up to g over 1 Myr in DB WDs Girven et al. (2012) DBZ DAZ

7 What causes WD pollution? NASA/JPL-Caltech Asteroids NASA/JPL-Caltech Comets Planets Gemini Observatory Jon Lomberg Compositionally Dynamically

8 What causes WD pollution? NASA/JPL-Caltech Asteroids Graham et al. (1990) Jura (2003, 2008) Bonsor et al. (2011) Debes et al. (2012) Bear & Soker (2013) Frewen & Hansen (2014) Veras et al. (2014a,b) NASA/JPL-Caltech Comets Planets Gemini Observatory Jon Lomberg

9 Asteroid Challenges Unknown accompanying planet(s) One planet + One belt Bonsor, Mustill & Wyatt (2011) Kuiper belt scattered inward Debes, Walsh & Stark (2012) Resonant diffusion towards WD Frewen & Hansen (2014) Planet mass and eccentricity dependence

10 Asteroid Challenges Unknown accompanying debris Veras, Jacobson, Gänsicke (Submitted to MNRAS) 100m - 10km asymmetric asteroids

11 Asteroid Challenges Unknown accompanying debris Veras, Jacobson, Gänsicke (Submitted to MNRAS)

12 Asteroid Challenges Need self-consistent size Wyatt, Farihi, Pringle & Bonsor (2014) Mass power law exponent q t 2 sink + t2 disc (yr)

13 Asteroid Challenges Depleted during main-sequence Debes, Walsh & Stark (2012) Number of Exo-belts Median mass = 820MSS-belt log (M/M SS belt )

14 Asteroid Challenges Need to numerically resolve very close pericentre passages Veras, Leinhardt, Bonsor, Gänsicke (Submitted to MNRAS) Disruption Spreading

15 Asteroid Challenges Need to numerically resolve very close pericentre passages Veras, Leinhardt, Bonsor, Gänsicke (Submitted to MNRAS) time / years Formation timescale of eccentric rings Breakup distance / RWD

16 What causes WD pollution? NASA/JPL-Caltech Asteroids Alcock et al. (1986) Parriott & Alcock (1998) Jura (2011) Stone et al. (2014) Veras et al. (2014c) NASA/JPL-Caltech Comets Planets Gemini Observatory Jon Lomberg

17 Comet Challenges Need to incorporate Galactic tides, stellar flybys and mass loss Main sequence TMSyr orbital period / yr Regions of Motion for 0.02 Veras, Evans, Wyatt, Tout (2014) [ Great Escape III ] Beyond Hill Axes x z Nonadiabatic PostMS Rkpc TPAGB Adiabatic Nonadiabatic Galactic MS Orbit Crossin g with Clo sest Stellar Flyby 8M 1M M 0 1M M 0 8M Bulge Disc Halo Distance to Galactic Centre / kpc

18 Comet Challenges Exo-Oort clouds not massive enough Veras, Shannon, Gänsicke (Submitted to MNRAS)

19 Comet Challenges Exo-Oort clouds not massive enough Veras, Shannon, Gänsicke (Submitted to MNRAS) GB Start

20 Distance / au Comet Challenges Composition-dependent dynamics Stone, Metzger & Loeb (Submitted to MNRAS) Sublimation distances comet comet ice comet rock WD cooling age / yr See Stone poster for more details! (#56) See Shannon poster for Oort cloud rockets! (#6)

21 What causes WD pollution? NASA/JPL-Caltech Asteroids Debes & Sigurdsson (2002) Veras et al. (2013) Voyatzis et al. (2013) Mustill et al. (2014) NASA/JPL-Caltech Comets Planets Gemini Observatory Jon Lomberg Next talk!

22 What about moons? Contains more mass than asteroids Regular delivery to WD dynamically unlikely (?) Hardest to model numerically (and perhaps analytically) See Payne poster! (#52)

23 Conclusions Origin of WD debris still mystery Dynamically, exo-oort cloud comets cannot be primary Total mass and delivery timescales still issues for asteroids Post-main-sequence planetary architectures largely unexplored

24 Semimajor axis in astronomical units Tidal engulfment distance for 1 planet Mustill & Villaver (2012) Time (Myr) Giant Planets Survive Planets Crash Stellar Radius Pulses

25 Semimajor axis in astronomical units Minimum mass in Jupiter masses Surviving the giant branch phases ENGULFED SURVIVED Exoplanets Solar System Planets Asteroid Belt Kuiper Belt Sedna Will planets be swallowed? Giant Mass in Jupiter masses ME MA V E

26 Planet motion: Mass- loss 2-body problem Giant Gyldén (1884) ; Mestschersky (1893) ; Jeans (1924)

27 Regimes of motion Veras, Wyatt, Mustill, Bonsor, Eldridge (2011) Giant Orbital Period << Mass Loss Timescale ADIABATIC REGIME Semimajor axis increases Eccentricity is constant Orbital Period >> Mass Loss Timescale RUNAWAY REGIME Semimajor axis increases more Eccentricity no longer constant

28 Adiabatic regime Veras, Wyatt, Mustill, Bonsor, Eldridge (2011) Giant Planet Planet AU 100 True Anomaly (deg) fdegrees Star Star AU Star Time/1000 yr Time (1000 yr)

29 Runaway regime Veras, Wyatt, Mustill, Bonsor, Eldridge (2011) Giant Planet Planet AU True Anomaly (deg) fdegrees AU Star Star Star Time/1000 yr Time (1000 yr)

30 The Solar System s Critical semimajor axis in 10 3 au a AU Stability Boundary The Solar System s Stability Boundary DANGER OF EJECTION BOUNDED Thermally Pulsing AGB Veras & Wyatt (2012) Model Η Number Early AGB RGB Giant

31 Anisotropic mass loss Giant Veras, Hadjidemetriou, Tout (2013)

32 :1 5:4 4:3 3:2 5:3 Initial Semimajor Axis Ratio Lo g 10 tinstyr Instability Times for M t 0 6M MS WD Hill Stability Boundary Veras, Mustill, Bonsor, Wyatt (2013) Full-lifetime simulations

33 Observation Motivation Disc shape change Gänsicke, Koester, Marsh, Southworth, Rebassa-Mansergas (2008) WD

34 Link with observations WD Veras, Mustill, Bonsor, Wyatt (2013) EjectionHyper Orbit PlanPlan Hit WD Collision 25 Number of of Unstable unstable Systems WD systems M 0 5M SIMULATED Log 10 White Dwarf Cooling Ageyr Log 10 [White Dwarf Cooling Age] /yr An Observed Polluted WD Sample OBSERVED SAMPLE Number of WD polluted systems Number of WD Polluted Systems Log 10 White Dwarf Cooling Ageyr

35 Hill Stability Marchal & Bozis (1982) Milani & Nobili (1983) Gladman (1993) Georgakarakos (2008) MS Donnison (2011) Veras, Mustill, Bonsor, Wyatt (2013)

36 Lagrange Stability Barnes & Greenberg (2006, 2007) Raymond et al. (2009) Veras & Mustill (2013) MS log 10 x 5.2 µ M J /M 0.18

37 Many planets Chambers et al. (1996) Chatterjee et al. (2008) Smith & Lissauer (2009) MS

38 How big? Giant Veras, Mustill, Bonsor, Wyatt (2013) Sun

39 How much mass lost? Giant Veras, Mustill, Bonsor, Wyatt (2013) All stars lose over half of their mass

40 Mutual Hill Radii Multi-planet instability 8 Debes & Sigurdsson (2002) Giant Log t (orbits) Without Mass Loss With Constant Mass Loss

41 Multi-planet instability from strong mass loss Giant Voyatzis, Hadjidemetriou, Veras, Varvoglis (2013) Mass Loss Stopped Planet 1 Planet 2 Time (kyr)

42 Multi-planet instability MS Mustill, Veras, Villaver (2014) Giant WD

43 Initial Semimajor Axis Ratio Veras, Mustill, Bonsor, Wyatt (2013) 30 Survivor Orbits for M t 0 5M Semimajor WD 25 Axes DistanceAU Pericentres Max AGB Radius

44 1 planet, 1 star, 0 discs Veras, Evans, Wyatt, Tout (2014)

45 Veras, Shannon, Gänsicke (Submitted to MNRAS 2014) Exo-Oort clouds Extends from 10 4 au 10 5 au Radial distributions a 1,a 1.5,a 2 Inclinations sin i Eccentricities random Orbital angles random # of comets per sim: 5000

46 Veras, Shannon, Gänsicke (Submitted to MNRAS 2014) Comet escape from close flyby

47 Observation Motivation Bowler et al. (2010) Absence of planets at low semimajor axes Giant Star Stellar Mass Planets

48 Observation Motivation Gänsicke, Marsh, Southworth, Rebassa-Mansergas (2006) Gaseous discs Points =Ca II emission line profiles

49 Observation Motivation Koester (2013) Typical WDs DB He lines DA H lines

50 Atmospheric sinking time / yr Observation Motivation Wyatt, Farihi, Pringle, Bonsor (2014) Sinking timescales He-dominated DB H-dominated DA Time after becoming white dwarf / yr

51 Observation Motivation Gänsicke et al. (2012) Metal pollution is diverse

52 Observation Motivation Klein, Jura, Koester, Zuckerman, Melis (2010) Some pollution is Earth-like White dwarf GD 40

53 Observation Motivation Farihi, Gänsicke, Koester (2013) Some pollution includes water White Dwarf

54 Age/yr Fate of Earth Schröder & Connon Smith (2008) Giant Earth Orbit Mass of Sun log 10 (d/r ) Red Giant Branch Asymptotic Giant Branch

55 Asteroid Challenges Circularising eccentric rings Veras, Leinhardt, Gänsicke (In Prep) Sublimation + PR-Drag 10 Semimajor axis decrease from radiation 1 aau R 10 4 m R 10 3 m R 10 2 m R 10 1 m R 10 0 m R 10 2 m R 10 4 m R 10 6 m tmyr