1. FOMALHAUT Review and evidence for a planetary system Paul Kalas University of California at Berkeley with support from NSF Center for Adaptive Optics NASA Origins Program STScI/AURA GO-9475, GO-9861, GO-9862, GO-10228 kalas (at) astron.berkeley.edu http://astron.berkeley.edu/~kalas

2. An early observation of a debris disk "The light at its brightest was considerably fainter than the brighter portions of the milky way... The outline generally appeared of a parabolic or probably elliptical form, and it would seem excentric as regards the sun, and also inclined, though but slightly to the ecliptic." -- Captain Jacob 1859 Introduction: Vega Phenomenon

3. Leinert & Gruen 1990 Thermal IR excess from Zodiacal dust cloud Introduction: Vega Phenomenon ~150 K

4. The Vega Phenomenon The discovery of excess emission from main sequence stars at IRAS wavelengths (Aumann et al. 1984). Introduction: Vega Phenomenon Backman & Paresce 1993 "The Big Three"

5. Direct Image of  Pic Dust Disk as early as 1983 Smith & Terrile 1984 Introduction: Vega Phenomenon Beta Pic was the Rosetta Stone Debris Disk for 15 years >300 refereed papers

6. And how about Fomalhaut? Optical ground-based coronagraphy No detection. Kalas & Jewitt 1996  Pic would remain the flagship debris disk for 14 years

7. Replenishment Age of system >> lifetime of dust Artymowicz 1997  Pic Introduction: Vega Phenomenon Artymowicz 1997 (Also applicable to Fomalhaut)

8. 0.5  m 2.2  m 10-20  m 850  m  Pic Vega Fomalhaut  Eri HR 4796A HD 141569 Introduction: Vega Phenomenon Resolved images of dust structure linked to unseen planets glow

9. Structure: Effects of unseen planets Dermott et al. 1994 resonant trapping by Earth Rings & Blobs (Zody & KB) Holes (most common) Vertical Warps (  Pic) Mouillet et al. 1997 secular perturbation in beta Pic Roques et al. 1994 resonant trapping and ejection

10. Disk Holes = Planet Formation? (Ozernoy et al. 2000) 850  m Data Links: Structure Planet+dust Simulation 2 M J at 50-60 AU low eccentricity Vega eps Eri 2 M J 0.2 M J

11. FOMALHAUT: IRAS (1984-1990) Extended at 60 microns Backman & Paresce 1993 36" source diameter, ~30 micron grains, T max ~75 K

12. FOMALHAUT: JCMT at 800 microns (1993) Zuckerman & Becklin (1993) Extended north-south, PA = 0˚ ± 30˚

13. FOMALHAUT: Sub-mm (1998) Holland, Greaves, Zuckerman et al. 1998 see also Dent et al. (2000) for modeling and analysis SED Fitting T = 40 K a = 100  m dominant a = 10  m < 10% of total M dust = 1.4 - 1.5 lunar Image Fitting A belt, 100-140 AU radius Sharp outer cutoff  collision =2x10 5 yr at 100 AU Discovery of 2 peaks ~10” radius (77 AU) 60 AU radius cavity

14. FOMALHAUT: Age Barrado y Navascues et al. 1997, 1998 Gliese (1969) suggested that Fomalhaut and Gl 879 (K5Ve) are a physical pair. Castor Moving Group

15. Search for debris disks around AU Mic AU Microscopii - Past Circumstellar Properties Deltorn & Kalas, unpublished.

16. FOMALHAUT: Age Age = age of Gl 879 = 200 ± 100 Myr Isochrones at 3, 10, 35, 70 Myr and ZAMS Barrado y Navascues et al. 1997, 1998

17. FOMALHAUT: Age Between a  Pic and a Kuiper Belt Adapted from Zuckerman 2001 (ARAA) Dust abundance vs. age

18. FOMALHAUT: Revisited at 450 & 850 microns A non-uniform ring Holland et al. 2003; also Wyatt & Dent 2002

19. FOMALHAUT: Inner arc or clump? 3  detection, 100 AU from star, 50 AU in length Model belt: 125-185 AU, peak at 135 AU Flux from arc is 5% of total, ~0.075 lunar mass Offset ring or pericenter glow cannot fit the asymmetry Instead, centered ring, but asymmetric density from 1:1 MMR Holland et al. 2003; also Wyatt & Dent 2002

20. FOMALHAUT: Spitzer spatially resolved at 24, 70 & 160  m Stapelfeldt et al. 2004

21. FOMALHAUT: Spitzer Stapelfeldt et al. 2004 ring eccentricity in model = 0.07 planet orbit:a = 40 AU, e = 0.15 160 70 24

22. FOMALHAUT: 350  m + Spitzer Marsh et al. 2005 69 AU resolution at 350 micron Ring with no inner clump T = 42 K Model fit using Spitzer ( 24, 70, 160  m) & 350  m image suggests 8 AU center of symmetry offset. Planet a = 86 AU, e = 0.07, M > 1 Earth if the inner ring boundary is the location of a 2:3 MMR (Neptune :CKB)

23. HST/ACS Search for Planets "ACS detection of sub-stellar companions around Vega, Fomalhaut and Beta Pic via parallax & proper motion" Cycle 12 GO Program: Kalas, Graham & Clampin Co-moving companions are detectable within a few months using the ACS/HRC (25 mas/pixel, FWHM = 60 mas). The existence of planets is inferred from disk structure observed in the sub-mm With age ~200 Myr and distance ~7.7 pc, thermal flux from cooling Jupiters and brown dwarfs may be detected in the HRC F814W broadband filter (I- band). F814W = 26 mag for 1 Jupiter mass. F814W = 22 mag for 10 Jupiter mass Fomalhaut Field Source May 17 - Sep. 27, 2004 I = 23.5 mag

24. Fomalhaut Optical Discovery

25. HST ACS planet search Hubble Space Telescope JCMT SCUBA 450 micron map (Wyatt & Dent 2002) HST Fomalhaut detection -- consistent with sub-mm maps

26. HST ACS planet search Fomalhaut F814W: 80 min., 17 May, 02 Aug, 27 Oct, 2004 F606W: 45 min., 27 Oct. 2004 25 mas / pix, FWHM = 60 mas = 0.5 AU Kalas, Graham & Clampin 2005, Nature, Vol. 435, pp. 1067 Semi-major axis: a =140.7± 1.8 AU Semi-minor axis: b = 57.5 ± 0.7 AU PA major axis: 156.0˚±0.3˚ Inclination: i = 65.9˚± 0.4˚ Projected Offset: 13.4 ± 1 AU PA of offset: 156.0˚ ± 0.3˚ Deprojected Offset f = 15.3 AU Eccentricity: e = f / a = 0.11 orbital period at 140 AU = 1200 yr No inner clumps

27. HST ACS planet search Model Disk Fitting inner & outer radius inclination to line of sight scattering phase function Grain number density function of radius and height

28. HST ACS planet search Asymmetric Scattering Phase Function |g| = 0.2 Zodiacal Light = +0.2; Forward Scattering Median size ~30 microns (blowout size for Fomalhaut is 7 microns). Model subtraction emphasizes inner dust component. 1-2 mag fainter than Q3. SE is 1.7 times brighter than NW. Inner dust component also detected in thermal infrared by Holland et al. 2003 and Stapelfeldt et al. 2004.

29. HST ACS planet search Belt width as a function of azimuth caveat the missing information: 1) Fomalhaut's belt is narrowest near apastron 2) No clear evidence for azimuthal structure Circular annulus with inner radius 133 AU, outer annulus 158 AU

30. HST ACS planet search Radial cut along 10˚ segment Q2 (apastron), in the illumination corrected image; cut traces the material surface density of the structure rather than its brightness. Cuts were actually made in 2˚ increments such that we show the mean value and the error bars are the standard deviation per measurement. Thus the error bars indicate the degree of azimuthal noise, whereas the overall modulation of points radially indicates the radial noise. Blue line is the model fit: 1)Knife-edge inner edge = 133 AU 2)n(r) = n(r o ) r -9 3)Scale height = 3.5 AU at 133 AU Evidence for a planetary system: Knife-edge inner boundary

31. Evidence for planets: sharp inner edges Kuiper Belt dust models by Moro-Martin & Malhotra 2002 1)Dust produced by KBOs a=35-50 AU, i = 0˚-17˚ 2)1-40  m,  = 2.7 g cm -3 & 3-120  m,  =1 g cm -3 3)7 planet, or no planets 4)Solar gravity, RP, P-R drag, solar wind drag.  = RP / gravity  L * /  s radial cuts no planets planets

32. HST ACS planet search Wyatt et al. 1999 How Observations of circumstellar disk asymmetries can reveal hidden planets:Pericenter glow and its application to the HR 4796A disk Wyatt, M.C. et al. 1999, ApJ, 527, 918 Particle eccentricity composed of a proper (or free) eccentricity, inherent to the particle, and a forced eccentricity due to a perturber. The pericenter also has a free and a forced component. The orbital distribution of particles with common forced elements will be a torus with center, C, offset from the stellar position, S. The forcing is due to an eccentric companion that could be either inside or outside the belt. Infer offset 2 AU for HR 4796A Similarly offset = 0.01 AU for Zodiacal dust disk (e.g. Kelsall et al. 1998). External eccentric perturber can produce the same center of symmetry offset, but not the sharp inner disk boundary. S = stellar position D = center of particle orbit C = center of precession circle P = pericenter of a particle orbit DP = a, semi-major axis of a particle orbit w f = direction of forced pericenter SD = a e SC = a e forced CD = a e proper Torus inner radius = a (1 - e proper ) = 133 AU Torus outer radius = a (1+ e proper ) G. Schneider, STIS Evidence for a planetary system: Center of symmetry offset

33. HST ACS planet search Fomalhaut Simulation Adam Deller & Sarah Maddison (Swinburne University of Technology) Planet Mass = 2 M_jupiter eccentricity = 0.3 semi-major axis = 70 AU

34. Architectures Planetary System Architectures: Solar System vs. Fomalhaut Kuiper Belt: 30 - 50 AU Sedna: Perihelion = 76 AU, Aphelion = 990 AU

35. Fomalhaut & the Kuiper Belt: A fairy tale 1.Truncation of disk by OB stellar radiation or dynamical perturbations in early star forming environment (make the outer edge first). 2.Disk heating and mass loss lead to an unstable system. 3.Unstable systems lead to giant planet migration with larger eccentricities than found in dynamically cold (e=0.001) and massive disks. 4.Outward planet migration stops when disk material runs out, but will continue in more massive disks (makes the large inner edge). Larwood & Kalas 2001 Tsiganis et al. 2005

36. Architectures: Physical extent beta Pic AU Mic Fomalhaut HR 4796A HD 107146 Sun >>800 AU 200 AU 170 AU 160 AU 70 AU 50 AU

37. Disks placed at the same distance: Introduction: Vega Phenomenon

38. HST ACS planet search Fomalhaut's Belt: Significance to Astronomy 1.Fomalhaut's belt is the closest that has been resolved in scattered light. 2.Inclination 66˚ means that it can be studied around its entire circumference 3.B elt characteristics that are consistent with planet-mass objects orbiting Fomalhaut: 1) The belt center is offset from the stellar center by 15 AU ± 1 AU, demanding apsidal alignment by a planet, 2) Disk edges are sharper on the inner boundary compared to the outer boundary and consistent with our scattered light model that simulates a knife-edge inner boundary and dynamical models of planet-disk interactions. 4.Age 200-300 Myr, this is one of the oldest debris disk seen in scattered light. It is probably leaving the clean-up phase and progressing to a configuration similar to that of our solar system. 5.Replace Beta Pictoris as the debris disk Rosetta Stone? 6.Astrophysical Mirror to our Kuiper Belt?

39. Summary Questions: 1.Outer extent of the disk? 2.Color? Main belt vs. inner dust? 3.Width as a function of azimuth? 4.Azimuthal asymmetries? 5.Plausible companion properties? 6.Planet at large radii? 7.Exterior companion? 8.Co-moving blobs? Contact Info: Kalas (at) astron.berkeley.edu More information: http://www.disksite.com/ Reference: Kalas et al. 2005, Nature, Vol. 435, pp. 1067

40. HST ACS planet search Future HST/ACS Observations: Multi-color imaging of the entire belt in Cycle 14 (July - August 2006) Search for azimuthal asymmetries; e.g. Trojans Measure ring width as a function of azimuth Search for color gradients azimuthally and radially Characterize properties of Zodiacal dust analog; dust interior to the belt. Understand grain properties, source regions More Future Work: Are there planets? Detect the planet(s) directly. Keck II AO run in July, October. Are there external perturbers confining the outer belt boundary? Wide field multi- epoch search. What is the origin of the belt? Planet formation theory; migration; resonance vs. ejection. What are the orbital elements of a planet? Is Fomalhaut's belt a mirror of our young Kuiper Belt? What accounts for the factor of three difference in semi-major axis scale?

41. HST ACS planet search Future Work Elliot et al. 1981 Uranus ring occultation