2011A&A...526A.144L


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.04CEST14:32:30

2011A&A...526A.144L - Astronomy and Astrophysics, volume 526A, 144-144 (2011/2-1)

High-contrast optical imaging of companions: the case of the brown dwarf binary HD 130948BC.

LABADIE L., REBOLO R., VILLO I., PEREZ-PRIETO J.A., PEREZ-GARRIDO A., HILDEBRANDT S.R., FEMENIA B., DIAZ-SANCHEZ A., BEJAR V.J.S., OSCOZ A., LOPEZ R., PIQUERAS J. and RODRIGUEZ L.F.

Abstract (from CDS):

High-contrast imaging at optical wavelengths is limited by the modest correction of conventional near-IR optimized AO systems. We take advantage of new fast and low-readout-noise detectors to explore the potential of fast imaging coupled to post-processing techniques to detect faint companions of stars at small angular separations. We have focused on I-band direct imaging of the previously detected brown dwarf binary HD130948BC (HD130948B, HD130948C), attempting to spatially resolve the L2+L2 system considered as a benchmark for the determination of substellar objects dynamical masses. We used the lucky-imaging instrument FastCam at the 2.5-m Nordic Telescope to obtain quasi diffraction-limited images of HD130948 with ∼0.1'' resolution. In order to improve the detectability of the faint binary in the vicinity of a bright (I=5.19±0.03) solar-type star, we implemented a post-processing technique based on wavelet transform filtering of the image, which allows us to strongly enhance the presence of point-like sources in regions where the primary halo generally dominates. We detect for the first time the binary brown dwarf HD130948BC in the optical band I with a SNR ∼9 at 2.561''±0.007'' (46.5AU) from HD130948A and confirm in two independent datasets (2008 May 29 and July 25) that the object is real, as opposed to time-varying residual speckles. We do not resolve the binary, which can be explained by astrometric results posterior to our observations, which predict a separation below the telescope resolution. We reach a contrast of ΔI=11.30±0.11 at this distance, and estimate a combined magnitude for this binary I=16.49 ±0.11 and a I-J color of 3.29 ±0.13. At 1'', we reach a detectability 10.5mag fainter than the primary after image post-processing. We obtain on-sky validation of a technique based on speckle imaging and wavelet-transform post-processing, which improves the high-contrast capabilities of speckle imaging. The I-J color measured for the BD companion is slightly bluer, but still consistent with what is typically found for L2 dwarfs (∼3.4-3.6).

Abstract Copyright:

Journal keyword(s): instrumentation: high angular resolution - methods: observational - techniques: image processing - binaries: close - brown dwarfs - circumstellar matter

Simbad objects: 5

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Number of rows : 5

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 Cl Melotte 22 OpC 03 47 00 +24 07.0           ~ 2978 0
2 HD 130948 BY* 14 50 15.8107686483 +23 54 42.633203114   6.456 5.867     F9IV-V 252 0
3 NAME HD 130948BC BD* 14 50 16.00 +23 54 41.8           L4+L4 54 0
4 2MASSW J1841086+311727 BD* 18 41 08.61480 +31 17 27.9600           L4Vpec 18 0
5 * 15 Sge B BD* 20 04 06.2 +17 04 13           L4-5 32 0

    Equat.    Gal    SGal    Ecl

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2020.07.04-14:32:30

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