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  Two companions to HD 202206


  Last update: October the 14th 2005

 
 
 
  • "The CORALIE survey for southern extra-solar planets XIII. A pair of planets around HD 202206 or a circumbinary planet?"
    A.C.M. Correia, S. Udry, M. Mayor, j. Laskar, D. Naef, F. Pepe, D. Queloz, N.C. Santos, 2004
    A&A 440, 751
    (ADS)
  • "The CORALIE survey for southern extra-solar planets VIII. The very low-mass companions of HD 141937, HD 162020, HD 168443, HD 202206: Brown dwarfs or "superplanets"?
    S. Udry, M. Mayor, D. Naef, F. Pepe, D. Queloz, N.C. Santos, M. Burnet, 2002
    A&A 390, 267
    (ADS)
  • ESO Press Release


  • Top: Best fit to the data (2-Keplerian fit)
    Bottom: Residual around the solution
    Larger image (374 kb)
    RV signal due to HD 202206 c.
    The signal from the inner body is removed.
    Larger image (284 kb)
     
     
    Temporal RV difference between the 2-Keplerian fit
    and the solution including the planet-planet interaction
    (solid line). The CORALIE residuals to the 2-Keplerian
    solution are also displayed (dots). Departures from this
    solution should be detected soon.
    Larger image (190 kb)
    Stability index D as a function of 2 parameters of the
    outer planet. Stable orbits have low D values (darkest
    regions). The labeled lines show the sqrt(chi^2) values
    for the selected parameters. Stable orbits exist near the
    minimum of chi^2 but the best fit solution is not stable.
    Larger image (350 kb)


  • 2-Keplerian orbital solution (from Correia et al. 2004):

    Object
    Period
    (days)
    T0
    (JD - 2 400 000)
    Eccentricity
    V
    (km/s)
    Omega
    (deg)
    Lambda
    (deg)
    K1
    (m/s)
    m2sini
    (M_Jup)
    a
    (AU)
    N
    Residuals
    (m/s)
    HD 202206 b
    256.20 +/- 0.03
    52175.6 +/- 0.2
    0.433 +/- 0.001
    14.721 +/- 0.001
    161.10 +/- 0.31
    265.60 +/- 0.13
    564.83 +/- 1.45
    17.5
    0.83
    105
    9.81
    HD 202206 c
    1296.8 +/- 19.1
    51206.4 +/- 29.9
    0.284 +/- 0.046
    -
    101.83 +/- 6.60
    31.54 +/- 2.67
    42.71 +/- 2.00
    2.41
    2.44
    "
    "


  • 3-body model assuming i=90 degrees (from Correia et al. 2004). Julian date of the parameters = 2452250.0:

    Object
    Period
    (days)
    Eccentricity
    V
    (km/s)
    Omega
    (deg)
    Lambda
    (deg)
    K1
    (m/s)
    m2sini
    (M_Jup)
    a
    (AU)
    N
    Residuals
    (m/s)
    HD 202206 b
    255.87 +/- 0.06
    0.435 +/- 0.001
    14.721 +/- 0.001
    161.18 +/- 0.30
    266.23 +/- 0.18
    564.75 +/- 1.34
    17.4
    0.83
    105
    9.65
    HD 202206 c
    1383.4 +/- 18.4
    0.267 +/- 0.021
    -
    78.99 +/- 6.65
    30.59 +/- 2.84
    42.01 +/- 1.50
    2.44
    2.55
    "
    "


  • Stellar properties:

    Parameter
    Value
    Reference
    Sp. Type
    G6V
    Hipparcos
    pi (mas)
    21.58
    Hipparcos
    d (pc)
    46.34
    Hipparcos
    m_v (mag)
    8.08
    Hipparcos
    B-V (mag)
    0.714
    Hipparcos
    T_eff (K)
    5765 +/- 40
    Santos et al. 2001
    M_v (mag)
    4.75
    -
    L (L_sol)
    1.07
    -
    log(g) (CGS)
    4.75 +/- 0.20
    Santos et al. 2001
    M_1 (M_sol)
    1.15
    Geneva models, Schaerer et al. 1993
    log(R'HK)
    -
    -
    P_rot (d)
    -
    -
    Vsini (km/s)
    2.5
    Coralie
    Age (Gyr)
    5.6 +/- 1.2
    Geneva models, Schaerer et al. 1993
    [Fe/H]
    0.37 +/- 0.07
    Santos et al. 2001

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    stephane.udry@obs.unige.ch