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

Questions1) 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 ? 3) are these disks left over debris of incomplete planetary formation ? 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 ? 6) when DD evolution begins ? 8 Myr following de la Reza et al. 2005

Motivation

COROT can in principle detect for the first time the passage of dust structures or planets in unresolved Debris Disks candidates.

-- Epsilon Eridani

distance 3.2 pcSpT K2V0.8 Msun

Planet 1 : Eps Eri bSemimajor axis 3.3 AUMass : 0.86 M JupiterMethod : Radial Velocities

Planet 2 : Eps Eri cUnconfirmedMass : 0.1 M JupiterMethod : Dust ring morphologySemimajor axis 40 AU

850 microns.

450 microns.

Superposedblack squares suggested BG features

AU Mic(Liu et al. 2004)

Beta Pic

(Lecavelier et al. 1997)

(Lecavelier et al. 1997)

(Lamers et al. 1997)

(Lamers et al. 1997)

(Lamers et al. 1997)

(Galland et al. 2005)

BD+31643 - 2Myr

1-HR4796 - 8Myr

2 – Bpic - 11Myr

3 – AB Aur - 4Myr

4 – HD32297 - ?5 – Fomahault - 200Myr

6 – Vega - 300Myr(123

4

5

6

AeBe – HD141569 - 5Myr

A

B

1 – HD107146 - 300Myr G

M Epsilon Eridani- 850Myr

K

1

2

2 – Tau Cet - 10Gyr

Au Mic - 11Myr

60 -

25

25 -12

Conclusions

Up to the present only one planet has been discovered in a resolved Debris Disk star (Epsilon Eridani).

One in a non resolved Debris Disk star (55 Cranc)

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 are in general M giants

We are now looking for hot B/A/F stars with IR excesses.