2010A&A...515A..17J


Query : 2010A&A...515A..17J

2010A&A...515A..17J - Astronomy and Astrophysics, volume 515, A17-17 (2010/6-1)

NACO-SDI imaging of known companion host stars from the AAPS and Keck planet search surveys.

JENKINS J.S., JONES H.R.A., BILLER B., O'TOOLE S.J., PINFIELD D.J., CLOSE L., TINNEY C.G., BUTLER R.P., WITTENMYER R., CARTER B. and DAY-JONES A.C.

Abstract (from CDS):

Direct imaging of brown dwarfs as companions to solar-type stars can provide a wealth of well-constrained data to ``benchmark'' the physics of such objects, since quantities like metallicity and age can be determined from their well-studied primaries. We present results from an adaptive optics imaging program on stars drawn from the Anglo-Australian and Keck Planet Search projects, with the aim of directly imaging known cool companions. Simulations have modeled the expected contrast ratios and separations of known companions using estimates of orbital parameters available from current radial-velocity data and then a selection of the best case objects were followed-up with high contrast imaging to attempt to directly image these companions. These simulations suggest that only a very small number of radial-velocity detected exoplanets with consistent velocity fits and age estimates could potentially be directly imaged using the VLT's Simultaneous Differential Imaging system and only under favorable conditions. We also present detectability confidence limits from the radial-velocity data sets and show how these can be used to gain a better understanding of these systems when combined with the imaging data. For HD32778 and HD91204 the detectabilities help little in constraining the companion and hence almost all our knowledge is drawn from the SDI images. Therefore, we can say that these stars do not host cool methane objects, out to on-sky separations of ∼2'', with contrasts less than 10-11mag. However, for HD25874, HD120780 and HD145825, the contrasts and detectabilities can rule out a number of possible solutions, particularly at low angular separations, and for the best case, down to strong methane masses of 40MJ at 1'' separation. The contrast curves constructed for these five stars show 5σ contrasts (ΔF1) of ∼9.2-11.5mag at separations of ≥0.6'', which correspond to contrasts of ∼9.7-12.0mag for companions of mid-T spectral type. Such limits allow us to reach down to 40MJ around fairly old field dwarfs that typically constitute high precision radial-velocity programs. Finally, the analysis performed here can serve as a template for future projects that will employ extreme-AO systems to directly image planets already indirectly discovered by the radial-velocity method.

Abstract Copyright:

Journal keyword(s): binaries: general - binaries: spectroscopic - planetary systems - stars: imaging - technique: radial velocities - techniques: high angular resolution

Simbad objects: 9

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Number of rows : 9
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 HD 25874 PM* 04 02 26.9793730553 -61 21 25.167093153   7.41 6.73     G2V 71 0
2 HD 32778 PM* 05 02 17.0376695709 -56 04 50.163527274 7.687 7.652 7.021 6.66 6.293 G7VFe-1.4CH-1.2 84 0
3 HD 91204 * 10 32 05.5005044280 +17 59 23.044554276   8.44 7.82     G0 58 0
4 HD 120780 PM* 13 52 35.8535675175 -50 55 18.149360729 8.833 8.28 7.391 6.886 6.4 K0V 82 0
5 HD 145825 PM* 16 14 11.9148076848 -31 39 49.154897988   7.21 6.54     G3V 86 0
6 * 15 Sge PM* 20 04 06.2207683221 +17 04 12.676556401   6.390 5.788 5.4   G0V 360 0
7 * alf PsA b Pl 22 57 39.04625 -29 37 20.0533           ~ 193 1
8 * alf PsA ** 22 57 39.04625 -29 37 20.0533 1.31 1.25 1.16 1.11 1.09 A4V 1185 3
9 HD 218396 El* 23 07 28.7157209544 +21 08 03.310767492   6.21 5.953     F0+VkA5mA5 1030 0

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2022.08.09-01:10:23

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