相关论文: The Physical Properties of HD 3651B: An Extrasolar…
(Abridged) We present near-IR photometry and spectroscopy of HD 3651B, the low-luminosity, wide-separation (480 AU) companion to the K0V exoplanet host star HD 3651A. We find a spectral type of T7.5+/-0.5, a temperature of 780-840 K, and a…
We use new and published near-IR spectra, with synthetic spectra, to derive physical properties of three of the latest-type T dwarfs. A new R~1700 spectrum of the T7.5 dwarf HD 3651B, with existing data, allows a detailed comparison to the…
We report the discovery of T dwarf companions to the nearby stars HN Peg (G0V, 18.4 pc, ~0.3 Gyr) and HD 3651 (K0V, 11.1 pc, ~7 Gyr). During an ongoing survey of 5'x5' fields surrounding stars in the solar neighborhood with IRAC aboard the…
The substellar companion HD206893b has recently been discovered by direct imaging of its disc-bearing host star with the SPHERE instrument. We investigate the atypical properties of the companion, which has the reddest near-infrared colours…
In the course of our ongoing multiplicity study of exoplanet host stars we detected a faint companion located at ~43arcsec (480AU physical projected separation) north-west of its primary -- the exoplanet host star HD3651 at 11pc. The…
The physical properties of brown dwarf companions found to orbit nearby, solar-type stars can be benchmarked against independent measures of their mass, age, chemical composition, and other parameters, offering insights into the evolution…
We present the discovery of a brown-dwarf companion to the 130-400 Myr-old G8 V star HD 203030. Separated by 11.9" (487 AU in projection) from its host star, HD 203030B has an estimated mass of 0.023 (+0.008;-0.011) solar masses. The K-band…
The determination of the fundamental properties (mass, separation, age, gravity and atmospheric properties) of brown dwarf companions allows us to infer crucial informations on their formation and evolution mechanisms. Spectroscopy of…
Context. Detecting and characterizing substellar companions for which the luminosity, mass, and age can be determined independently is of utter importance to test and calibrate the evolutionary models due to uncertainties in their formation…
We report the discovery of a wide (approximately 400 AU projected separation), common proper motion companion to the nearby M dwarf LHS 2803 (PSO J207.0300-13.7422). This object was discovered during our census of the local T dwarf…
We aim to reveal the nature of the reddest known substellar companion HD 206893 B by studying its near-infrared colors and spectral morphology and by investigating its orbital motion. We fit atmospheric models for giant planets and brown…
Upon its discovery in 2006, the young L7.5 companion to the solar analog HD 203030 was found to be unusual in being $\approx$200 K cooler than older late-L dwarfs. HD 203030B offered the first clear indication that the effective temperature…
We report the discovery of a substellar companion to the nearby solar-type star HD 46588 (F7V, 17.9 pc, ~3 Gyr). HD 46588 B was found through a survey for common proper motion companions to nearby stars using data from the Wide-field…
We report on the discovery of a fourth component in the HD 221356 star system, previously known to be formed by an F8V, slightly metal-poor primary ([Fe/H]=-0.26), and a distant M8V+L3V pair. In our ongoing common proper motion search based…
We report here the discovery and characterization of a high-mass transiting brown dwarf in a close-in orbit around its host star, TOI-7154. Initially, the host star was identified as an exoplanetary candidate from the TESS photometry data.…
Using high-contrast imaging with the SPHERE instrument at the VLT, we report the first images of a cold brown dwarf companion to the exoplanet host star HD4113A. The brown dwarf HD4113C is part of a complex dynamical system consisting of a…
Context: HR2562B is a planetary-mass companion located 0.56arcsec (19au) from its host star. It is one of a few L/T transitional objects orbiting a young star. This companion provides insight into the evolution of young objects in the L/T…
In our ongoing deep infrared imaging search for faint wide secondaries of planet-candidate host stars we have confirmed astrometrically the companionship of a low-mass object to be co-moving with HD89744, a companion-candidate suggested…
We have found a very faint companion to the active solar analog HR 7672 (HD 190406; GJ 779; 15 Sge). Three epochs of high resolution imaging using adaptive optics (AO) at the Gemini-North and Keck II Telescopes demonstrate that HR 7672B is…
The mass and age of substellar objects are degenerate parameters leaving the evolutionary state of brown dwarfs ambiguous without additional information. Theoretical models are normally used to help distinguish between old, massive brown…