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Stellar Rotation in the CoRoT Era
Jose Dias do Nascimento Jr José Renan de
Medeiros and team DFTE- Natal Departamento de
Física Teórica e Experimental, Brazil
2-6 November 2005 SECOND COROT- BRASIL
WORKSHOP Ubatuba, SP
AcRoCOROT Home Page
http//ace.dfte.ufrn.br/corot/index.html
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Accepted CoRoT Proposals
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Team of Proponents II J.R. De Medeiros(1),
J.D. Do Nascimento(1), C.H.F. Melo(7) A.
Domiciano de Souza(2) M.-J. Goupil(3) A.-M.
Hubert(3) G. Jasniewicz(5) P. de Laverny(4)
A.Lebre(5) A. Maeder(6), G.P. Mello(8) E.J.
Pacheco(9) L. Pasquini(7) E. Peloso(8) G.
Quast(13) A. Recio-Blanco(4) F. Royer(4) L.
Silva(11) A. Silva(12) C.A. Torres(13)
Team of Proponents I J.R. De Medeiros(1),
J.D.Jr Do Nascimento(1), G. Cutispoto(2) A.
Domiciano de Souza(3) M.-J. Goupil(4) P. de
Laverny(5) A.Lebre(6) A. Maeder(7) C.H.F.
Melo(8) G.P. Mello(9) S. Messina(2) E.J.
Pacheco(10) P.S. Parihar(14) L. Pasquini(8) E.
Peloso(9) A. Recio-Blanco(5) A.I. Ribas(11) F.
Royer(4) A. Silva(12) L. Silva(13)
1) Departamento de Física, U. Federal do Rio
Grande do Norte, Brazil 2) 0ssevatorio di
Catania, Catania, Italy 3) Max-Planck-Institute
Bonn, Germany 4) 0bservatoire de Paris, Meudon
cedex, France 5) 0bservatoire de Ia Cote d'Azur,
Nice, France 6) Groupe d'Astrophysique, U. de
Montpellier, Montpellier, France 7) 0bservatoire
de Geneve, Switzerland 8) European Southern
Observatory 9) 0bservatorio do Valongo, Rio de
Janeiro, Brazil 10) Universidade de São Paulo,
São Paulo, Brazil 11) Inlnstitut de Ciències de
l'Espai (CSIC-IEEC), Barcelona, Spain 12)
Observatório Nacional, Rio de Janeiro, Brazil 13)
Universidade Mackenzie, São Paulo, Brazil 14)
Indian Institute of Astrophysics, Koramangala,
Bangalore, índia
1) Departamento de Física, U. Federal do Rio
Grande do Norte, Brazil 2) Max-Planck-Institute
Bonn, Germany 3) 0bservatoire de Paris, Meudon
cedex, France 4) 0bservatoire de Ia Cote d'Azur,
Nice, France 5) Groupe d'Astrophysique, U. de
Montpellier, Montpellier, France 6) 0bservatoire
de Geneve, Switzerland 7) European Southern
Observatory 8) 0bservatorio do Valongo, Rio de
Janeiro, Brazil 9) Universidade de São Paulo,
São Paulo, Brazil 10) Institut de Ciències de
1'Espai (CSIC-IEEC), Barcelona, Spain 11)
Observatório Nacional, Rio de Janeiro, Brazil 12)
Universidade Mackenzie, São Paulo, Brazil 13)
Laboratorio Nacional de Astrofísica, MG, Brazil
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I- The Sun in Time The History of the Solar
Angular MomentumEvolution
Abstract
On the basis of data for a statistically robust
sample of stars from the CoRoT Exofield Long
Runs, we intend to carry out an unprecedented
study on the evolution of the solar angular
momentum. The stars composing the sample have as
main characteristics a solar metallicity and are
located along the evolutionary track of 1.0 M0 on
the different stages from the main sequence to
the basis of the giant branch. The obtained
rotational period will enable us to analyze the
behavior of the rotation with age and the
mechanisms playing a major role on the evolution
of this fundamental parameter. From this
information, for solar-like stars, it will be
possible to write a comparative history of the
angular momentum of the Sun ali along its life,
from the main sequence to the red giant stages.
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II- Stellar rotation in CoRoT Era The Stellar
Angular Momentum Historyin HR Diagram
Abstract
On the basis of CoRoT observations for a
statistically robust sample of stars from the
CoRoT Sismo and Exofield Long Runs, we intend to
carry out an unprecedented study on the behavior
of the stellar rotation along the HR diagram.
Rotation period obtained from light modulation,
combined with other stellar parameters, will
enable us to analyze the behavior of rotation as
a function of luminosity, mass, age and
metallicity. From this study we hope to oífer
solid constraints for models of stellar
evolution, as well as for the study of mechanisms
controlling activity and chemical mixing in
different stages of the stellar evolution.
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Scientific Motivation

• Stellar Rotation is one of the most important
  observable in stellar astrophysics, driving
  largely the stellar evolution

- The Stellar Angular Momentum History in HR
Diagram - The link of rotation with stellar
parameters - The role of rotation on stellar
internal and external phenomena
These two proposals are in fact complementary
- Different timescales (from days to hundreds of
days) - Optimized for different S/N of the
data - Similar techniques of time series
analysis and modelling - Dependence of
rotation on stellar mass In Fact, rotation is
not an optional stellar astrophysical parameters
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Scientific Motivation

• Questions
• Is the sun typical for its mass and age ?
• Has the presence of planets influenced rotation
  ?
• How did the sun get where it is today ?
• Is the rotation indicative of sub-surface
  phenomena ?
• - Differential rotation
• - Rotation and activity cycles
• - Rotation and mixing and A rapid rotation core ?
• Rotation versus chemical abundances
• Rotation versus atmospheric emission fluxes
• Rotation and binarity
• Are the Stellar Axes distributed randomly ?

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ROTATION AT ONE SOLAR MASS(some previous
claims)What we know about Stellar Rotatoin

• Krafts 67 Obvious drop in rotation at 1 Solar
  Mass and Activity stars are faster rotators
• late F dwarfs lose angular momentum during
  their main sequence life times.
• Skumanich72 Quantified a relation t-1/2 for
  rotation, Ca II emission

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ROTATION AT ONE SOLAR MASSMilestonesWhat we
know about Stellar Rotatoin

• Soderbom83 Rotation of late type stars and the
  rotational history of the sun. The t -1/2
  relation cannot hold for stars much younger than
  the pleiades. Some open questions...
• Do 1.25 Solar Mass stars also follow a t -1/2
  relation ?
• Other Classes of stars as massive as the sun
  follow this relation ?
• Pace and Pasquini 2004 Proposed a new t-?
  relation on the basis of larger stellar sample
  than previous studies.

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What we know about Stellar Period of Rotation
Evolution ?
Skumanich (1972) showed that Krafts Hyades
and Pleiades data together with the rotational
velocity of the Sun, were consistent with the
relation v t-1/2 So, Activity Rotation
Prot
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What we know about Stellar Rotation !
Evolution of Projected rotational velocities
Distribution of Vsini on the HR Diagram CORAVEL
Measurements (De Medeiros Mayor
1999) Tracks From do Nacimento et al.
1999 Toulouse Geneve Evolutionary Code
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What we know about Stellar Rotation !
Projected rotational velocities For 1 Msun
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Evolution of Rotation Periods for FGK and M
Rotation Period for a sample of about 1400
FGK and M stars from the MS to the turnoff

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Evolution of Rotation Periods for FGK M
Rotational Period for a sample of about 1400
FGK and M stars from the MS to the
turnoff
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Distribution of Rotational Periods
(Do Nascimento and De Medeiros 2005)
- The behavior of stellar Rotational Periods for
Main Sequence Stars
Impact of high-precision (up to 150 days)
observations!!!
(Do Nascimento and De Medeiros 2005)
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M67 solar-age open cluster a laboratory for the
Sun in time (see Poster No 1 by Canto-Martins et
al.)
Color-magnitude diagram of the open cluster
M67 Stars composing our sample are labeled with
red cross symbols. Rotation, activity
diagnostics, chemical abundances and single or
multiplicity status for all the stars
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What family of stars we plan to observe with
CoRoT
Temperature (spectral type)

• F, G and K spectral type stars, following defined
  evolutionary tracks
• Stars with previously defined parameters
• Stars with single or multiple previously defined
  status
• Seismology
• Long runs (150 days)
• accurate spectrum analysis
• main sequence A, F, G
• targets of solar mass, ? Scuti, ? Dor, ? Cep
• Short runs (20 days)
• Processes across the HR diagram
• Exofield
• red dwarfs
• spectral types F to M

-5 0 5 10 15
? Ceph
Cepheids
SPB
Giants
RR Lyrae
? Scuti
? Dor
sdB
Mv
Solar type
Main sequence
Priority targets for seismology
Targets for exoplanet search
O B A F G
K M
From Laurent Boisnard 1st Brazil COROT Workshop,
Natal, 30 Oct 2004
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What we need to obtain from CoRoT measurements

• High-precision as possible,(?F/F 10-4 - 10-3)
  observations
• Stars with apparent Visual Magnitudes
• 12 lt V lt 12.5 (ground observations with high
  signal to noise spectra )
• Claudio Melos Talk
• Observations in Short runs (20 days) and long
  runs (150 days) to study the processes across
  the HR diagram.

Prot(days)
70 60 50 40 30 20 10 0
SUN
30 50 100 200 300 600 800 4.5Gyr
AGE (Myr)
Light curves Baudin et al simulator Including
photon and granulation noise
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Expected (most important) difficulties

• I) Precise determination of stellar parameters
  to characterization of the sample (procedures by
  Recio-Blanco et al. (2005) and Silva et al.
  (2005))
• II) Multiplicity, including planet effects
• III) Spotted stars

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Stellar Chemical Abundances and Atmospheric
Parameters from the Gaia/RVS spectra
The algorithm MATISSE B functions
A. Recio-Blanco (in collaboration with P. de
Laverny, A. Bijaoui) Laboratoire
Cassiopée Observatoire de la Côte dAzur (France)
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Stellar Chemical Abundances and Atmospheric
Parameters from the Gaia/RVS spectra
Grid of synthetic spectra
Si (?)
?
?
?
log g
MARCS collaboration
?
?
?
?
?
?
? Dimensions -Atmospheric parameters
Teff, log g, M/H -?/Fe -Ca/H, Mg/H,
Si/H, Ti/H,
?
?
?
?
?
?
?
?
?
M/H
?
?
?
?
?
?
?
?
?
Teff
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Preparatory and followup stages and CoRoT data
center at Natal

• Official Brazil/Chile program to use chilean
  telescope time by the AcRoCoRoT Team (talk by
  Claudio Melo)
• CoRoT Data Center at Natal conducted and operated
  by Departamento de Informática e Matemática
  Aplicada - UFRN, supported by CNPq, CAPES and
  FAPERN in collaboration with
• INPE (Brazilian Center of Missions at Natal)

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Expected COROT samples

• we can estimate
• - About 220 objects with 11ltVlt12.5 in the F to K
  
• spectral range - exp. accuracy (100-150)10-6
  in 1-hr integration time
• We estimate from the Hipparcos photometry, that
  about 200 F-K stars with some variability
  (about 10-2 mag. or larger)
• See the poster SAMPLE SELECTION FOR THE ACCEPETD
  PROPOSAL The Sun in Time. (Peloso et al.)

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Conclusions
COROT will provide us with an new and solid
view of STELLAR ROTATION across the HR diagram.

• Our results will have an impact also on the core
  program and other additional science proposals,
  e.g.,
• - Magnetic activity
• - Oscillations
• - Microvariability
• - Binarity ...

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" CoRoT mission means also the harmonization and
solidarity among people,  represented by greater
symbols of the human intelligence their  
academic institutions and their achievements "
José Ivonildo Rêgo Rector / Federal
University of Rio Grande do Norte 
Thank you!!
AcRoCOROT Home Page
http//ace.dfte.ufrn.br/corot/index.html
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End
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What we know about the Angular Momentum
Evolution ?
The angular momentum per gram as a function
of Log M.
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