Are Planets in Unresolved Candidates of Debris Disks Stars? R. de la Reza (1), C. Chavero (1), C.A.O. Torres (2) & E. Jilinski (1) ( 1) Observatorio Nacional - Rio de Janeiro (2) Laboratorio Nacional de Astrofísica

Properties Debris disks (DD) are evolved disks presenting the following properties: 1) in general absence or few gas content 1) in general absence or few gas content 2) structural pattern dominated by new generation dust produced by 2) structural pattern dominated by new generation dust produced by strong collisions of planetesimals strong collisions of planetesimals 3) in general disks are assymmetrical 3) in general disks are assymmetrical 4) presence of warps and local perturbations of the dust 4) presence of warps and local perturbations of the dust 5) longlife structures 5) longlife structures 6) difficult to be detected, only approximatley 12 are resolved 6) difficult to be detected, only approximatley 12 are resolved

Questions 1) are there planets hidden in their disks ? At present only one planet have been clearly detected around a resolved disk in Epsilon Eridani (Greaves et al. 2005) 2) are these disks failed planetary disks ? 2) are these disks failed planetary disks ? 3) are these disks left over debris of incomplete planetary formation ? 3) are these disks left over debris of incomplete planetary formation ? 4) are hidden planets producing the observed warps and assymmetries, gaps or rings ? 4) are hidden planets producing the observed warps and assymmetries, gaps or rings ? 5) why they are longlived structures ? what maintain their dynamical stability ? is that due to a special configuration of dust maintained in resonances and what is the role of eventual planets ? 5) why they are longlived structures ? what maintain their dynamical stability ? is that due to a special configuration of dust maintained in resonances and what is the role of eventual planets ? 6) when DD evolution begins ? 8 Myr following de la Reza et al ) when DD evolution begins ? 8 Myr following de la Reza et al COROT can in principle detect for the first time the passage of dust structures or planets in unresolved Debris Disks candidates. Motivation

Distance: 3.2 pc SpT: K2V M * :0.8 Msun Planet 1 : Eps Eri b a: 3.3 AU M p : 0.86 M Jup Method : RV Planet 2 : Eps Eri c -Unconfirmed a: 40AU M p : 0.1 M Jup Method : Dust ring morphology 850 microns. 450 microns. Epsilon Eridani Epsilon Eridani The only example of a DD star with a planet close to the star detected by radial velocity surveys. Planet 2 is sheppering the ring?

β Pic The β Pic star with an edge-on disk. This is an example of a convenient geometry for COROT observations.

(Lecavelier et al. 1997) Unique emission absortion event detected on Nov 10 th 1981 by ground based photometric observations

(Lecavelier et al. 1997) 1 First interpretation of the 1981 event; a planet into the disk.

(Lamers et al. 1997) 2 3 Two other geometrical interpretations: 2-a spherical cloud; 3- a cometary cloud falling into the star.

(Lamers et al. 1997) The most successful model (3); a large comet or a fragmented falling comet.

(Galland et al. 2005) Result of a radial velocity survey of the β Pict star

Search for DD candidates stars for COROT: Distribution of resolved DD stars in an IRAS Color-Color diagram BD Myr 1-HR Myr 2 – Bpic - 11 Myr 3 – AB Aur - 4 Myr 4 – HD ? 5 – Fomahault - 200Myr 6 – Vega Myr (1( AeBe – HD Myr A B 1 – HD Myr G M Epsilon Eridani- 850Myr K – Tau Cet - 10Gyr Au Mic - 11Myr B BD A 1-HR Bpic 3 - AB Aur 4 - HD Fomahault 6 - Vega F AeBe- HD G 1- HD Tau Cet K Epsilon Eridani M Au Mic

Unresolved DD candidate stars with high IRAS quality

Conclusions Up to the present only one planet has been discovered in a resolved Debris Disk star (Epsilon Eridani). CoRoT can in principle discover some new cases and give an important insight on studies of the evolution of Debris Disks and on planetary formation. The only problem is the difficulty to find targets for 11<V<14 M type DD candidates obtained from IRASare in general M giants stars We are now looking for hot B/A/F stars with IR excesses. References: De la Reza et al., submitted to the AJ Galland et al., 2005 A&A, 443,337 Lamers et al.., 1997, A&A 328, 321 Lecavelier des Etangs, 1997, A&A, 328, 311