Hokupa'a-Gemini Discovery of Two Ultracool Companions to the Young Star HD 130948

Potter, D.; Martín, E. L.; Cushing, Michael C.; Baudoz, Pierre; Brandner, W.; Guyon, Olivier; Neuhäuser, R.

doi:10.1086/339999

Cited by 127 publications

(136 citation statements)

References 31 publications

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“…We are searching for sub-stellar companions also on the southern sky, with speckle and normal imaging at the ESO NTT, and now also with AO (NAOS-CONICA at the ESO VLT). Four sub-stellar companions to young (nearby) stars have been confirmed by both proper motion and spectroscopy: The ∼12 Myrs young TWA-5 B (Lowrance et al 1999;Neuhäuser et al 2000), the ∼300 Myrs old Gl 569 B, C Lane et al 2001), the ∼35 Myrs young HR 7239 B (Lowrance et al 2000;Guenther et al 2001), and the ∼300 Myrs old HD 130948 B, C (Potter et al 2002;Goto et al 2002).…”

Section: Introductionmentioning

confidence: 85%

HD 77407 and GJ 577: Two new young stellar binaries

Mugrauer

Neuhäuser

Guenther

et al. 2004

A&A

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Abstract. We present the first results from our search for close stellar and sub-stellar companions to young nearby stars on the northern sky. Our infrared imaging observations are obtained with the 3.5 m Calar Alto telescope and the AO system ALFA. With two epoch observations which were separated by about one year, we found two co-moving companion candidates, one close to HD 77407 and one close to GJ 577. For the companion candidate near GJ 577, we obtained an optical spectrum showing spectral type M 4.5; this candidate is a bound low-mass stellar companion confirmed by both proper motion and spectroscopy. We estimate the masses for HD 77407 B and GJ 577 B to be ∼0.3 to 0.5 M and ∼0.16 to 0.2 M , respectively. Compared to Siess et al. (2000) models, each of the two pairs appears co-eval with HD 77407 A, B being 10 to 40 Myrs and GJ 577 A, B being ≥100 Myrs old. We also took multi-epoch high-resolution spectra of HD 77407 to search for sub-stellar companions, but did not find any with 3 M Jup as upper mass (m sin i) limit (for up to 4 year orbits); however, we detected a long-term radial velocity trend in HD 77407 A, consistent with a ∼0.3 M companion at ∼50 AU separation, i.e. the one detected by the imaging. Hence, HD 77407 B is confirmed to be a bound companion to HD 77407 A. We also present limits for undetected, but detectable companions using a deep image of HD 77407 A and B, also observed with the Keck NIRC2 AO system; any brown dwarfs were detectable outside of 0.5 arcsec (17 AU at HD 77407), giant planets with masses from ∼6.5 to 12 M Jup were detectable at ≥1.5 arcsec.

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Section: Introductionmentioning

confidence: 85%

HD 77407 and GJ 577: Two new young stellar binaries

Mugrauer

Neuhäuser

Guenther

et al. 2004

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“…It is also member of the Tucana-Horologium association. HD 130948 BC is a BD binary system, companion to HD 130948 (Potter et al 2002). The total mass was estimated to be 0.1095 ± 0.0022 M (Dupuy & Liu 2011) and the age 0.93 Gyr.…”

Section: Datasetmentioning

confidence: 99%

The VLT/NaCo large program to probe the occurrence of exoplanets and brown dwarfs at wide orbits

Reggiani

Meyer

Chauvin

et al. 2016

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Context. In recent years there have been many attempts to characterize the occurrence and distribution of stellar, brown dwarf (BD), and planetary-mass companions to solar-type stars with the aim of constraining formation mechanisms. From radial velocity observations a dearth of companions with masses between 10-40 M Jupiter has been noticed at close separations, suggesting the possibility of a distinct formation mechanism for objects above and below this range. Aims. We present a model for the substellar companion mass function (CMF). This model consists of the superposition of the planet and BD companion mass distributions, assuming that we can extrapolate the radial velocity measured CMF for planets to larger separations and the stellar companion mass-ratio distribution over all separations into the BD mass regime. By using both the results of the VLT/NaCo large program (NaCo-LP) and the complementary archive datasets, which probe the occurrence of planets and BDs on wide orbits around solar-type stars, we place some constraints on the planet and BD distributions. Methods. We developed a Monte Carlo simulation tool to predict the outcome of a given survey, depending on the shape of the orbital parameter distributions (mass, semimajor axis, eccentricity, and inclination). Comparing the predictions with the results of the observations, we calculate the likelihood of different models and which models can be ruled out. Results. Current observations are consistent with the proposed model for the CMF, as long as a sufficiently small outer truncation radius ( 100 AU) is introduced for the planet separation distribution. Some regions of parameter space can be excluded by the observations. Conclusions. We conclude that the results of the direct imaging surveys searching for substellar companions around Sun-like stars are consistent with a combined substellar mass spectrum of planets and BDs. This mass distribution has a minimum between 10 and 50 M Jupiter , in agreement with radial velocity measurements. In this picture the dearth of objects in this mass range would naturally arise from the shape of the mass distribution, without the introduction of any distinct formation mechanism for BDs. This kind of model for the CMF allows us to determine the probability for a substellar companion as a function of mass to have formed in a disk or from protostellar core fragmentation, as such mechanisms overlap in this mass range.

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“…1 show the imaging results from our observations. In the upper-left corner we display the original detection by Potter et al (2002), in which the brown dwarf binary is resolved in the H-band with the 8-m Gemini-North telescope.…”

Section: Detection Of the Bd Companionmentioning

confidence: 99%

“…Our first measurement of the integrated I c magnitude of the HD 130948 BD companion allows us to compare it with existing data. We assume for HD 130948 BC a spectral type L2 ± 2 inferred by near-infrared spectroscopy by Potter et al (2002). The I − J color mean and dispersion in the estimated spectral type interval for the Liebert & Gizis (2006) sample equal 3.58 ± 0.17.…”

Section: Colormentioning

confidence: 99%

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

Labadie

Rebolo

Villó

et al. 2011

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Context. 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 postprocessing techniques to detect faint companions of stars at small angular separations. Aims. We have focused on I-band direct imaging of the previously detected brown dwarf binary HD 130948 BC, attempting to spatially resolve the L2+L2 system considered as a benchmark for the determination of substellar objects dynamical masses. Methods. We used the lucky-imaging instrument FastCam at the 2.5-m Nordic Telescope to obtain quasi diffraction-limited images of HD 130948 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. Results. We detect for the first time the binary brown dwarf HD 130948 BC in the optical band I with a SNR ∼ 9 at 2.561 ± 0.007 (46.5 AU) from HD 130948 A 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 10.5 mag fainter than the primary after image post-processing. Conclusions. 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).

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Hokupa'a-Gemini Discovery of Two Ultracool Companions to the Young Star HD 130948

Cited by 127 publications

References 31 publications

HD 77407 and GJ 577: Two new young stellar binaries

HD 77407 and GJ 577: Two new young stellar binaries

The VLT/NaCo large program to probe the occurrence of exoplanets and brown dwarfs at wide orbits

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

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