Are Planets in Unresolved CandidatesAre Planets in Unresolved Candidates

of Debris Disks Stars? of Debris Disks Stars?

R. de la Reza R. de la Reza (1)(1), C. Chavero , C. Chavero (1)(1), , C.A.O. Torres C.A.O. Torres (2)(2) & E. Jilinski & E. Jilinski (1)(1)

((1)1) Observatorio Nacional - Rio de Janeiro Observatorio Nacional - Rio de Janeiro (2)(2) Laboratorio Nacional de Astrofísica Laboratorio Nacional de Astrofísica

PropertiesProperties

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

QuestionsQuestions1)1) are there planets hidden in their disks ? At present only one planet are there planets hidden in their disks ? At present only one planet have been clearly detected around a resolved disk in have been clearly detected around a resolved disk in Epsilon Eridani Epsilon Eridani (Greaves (Greaves et al. 2005)et al. 2005) 2)2) are these disks failed planetary disks ? are these disks failed planetary disks ? 3)3) are these disks left over debris of incomplete planetary formation ? are these disks left over debris of incomplete planetary formation ? 4)4) are hidden planets producing the observed warps and assymmetries, are hidden planets producing the observed warps and assymmetries, gaps or rings ?gaps or rings ? 5)5) why they are longlived structures ? what maintain their dynamical why they are longlived structures ? what maintain their dynamical stability ? is that due to a special configuration of dust maintained in stability ? is that due to a special configuration of dust maintained in resonances and what is the role of eventual planets ?resonances and what is the role of eventual planets ? 6)6) when DD evolution begins ? when DD evolution begins ? 8 Myr8 Myr following de la Reza et al. 2005 following de la Reza et al. 2005

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

MotivationMotivation

Distance: 3.2 pcSpT: K2VM*:0.8 Msun

Planet 1 : Eps Eri ba: 3.3 AUMp : 0.86 M Jup

Method : RV

Planet 2 : Eps Eri c -Unconfirmeda: 40AUMp : 0.1 MJup

Method : Dust ring morphology

850 microns.

450 microns.

Epsilon EridaniEpsilon Eridani

The only example of a DD star with a planet close to the star detected The only example of a DD star with a planet close to the star detected by radial velocity surveysby 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 10Unique emission absortion event detected on Nov 10thth 1981 by ground based photometric observations1981 by ground based photometric observations

(Lecavelier et al. 1997)

1 First interpretation of the 1981 event; a planet into the disk.First interpretation of the 1981 event; a planet into the disk.

(Lamers et al. 1997)

2

3

Two other geometrical Two other geometrical interpretations:interpretations:

2-a spherical cloud;2-a spherical cloud;

3- a cometary cloud 3- a cometary cloud falling into the star.falling into the star.

(Lamers et al. 1997)

The most successful The most successful model (3); a large model (3); a large comet or a fragmented comet or a fragmented falling comet.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+31643 - 2Myr1-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

25 - 12

60 -

25

B BD+31643

A 1-HR4796 2 - Bpic 3 - AB Aur 4 - HD32297 5 - Fomahault 6 - Vega

F AeBe- HD141569

G 1- HD107146

2 - Tau Cet

K Epsilon Eridani

M Au Mic

-1.5

-1

-0.5

0

0.5

1

-1.5 -1 -0.5 0 0.5 1

25-12

60-25

B

A

F

G

K

photosphere

Unresolved DD candidate stars with high IRAS qualityUnresolved DD candidate stars with high IRAS quality

ConclusionsConclusionsUp 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