相关论文: Could the planets around HR 8799 be brown dwarfs?

Located at less than 2pc away, Luhman16AB (WISE.J104915.57-531906.1) is the closest pair of brown dwarfs and third closest `stellar' system to Earth. An exoplanet candidate in the Luhman16 binary system was reported in 2017 based on a weak…

We present new astrometric and spectroscopic data to confirm two new M/L dwarf systems, G124-62 and LHS5166, and discuss the nature of a third system (LP261-75). Age and thus mass determinations of the L dwarf companions are discussed based…

We present new evidence for a problem with cooling rates predicted by substellar evolutionary models that implies model-derived masses in the literature for brown dwarfs and directly imaged planets may be too high. Based on our dynamical…

Benchmark brown dwarfs are those objects for which fiducial constraints are available, including effective temperature, parallax, age, metallicity. We searched for new cool brown dwarfs in 186 sq.deg. of the new area covered by the data…

We present resolved Herschel images of a circumbinary debris disk in the 99 Herculis system. The primary is a late F-type star. The binary orbit is well characterised and we conclude that the disk is misaligned with the binary plane. Two…

We search for the astrometric signatures of planets and brown dwarfs known from radial velocity surveys in the improved Hipparcos intermediate astrometric data provided by van Leeuwen (2007a). Our aim is to put more significant constraints…

A transiting planet was recently discovered around a star in the Taurus star-forming region, IRAS 04125+2902, making it one of the youngest known planets. The discovery paper cited two age estimates for IRAS 04125+2902, one based on a…

The mass domain where massive extrasolar planets and brown dwarfs overlap is still poorly understood due to the paucity of brown dwarfs orbiting close to solar-type stars, the so-called brown dwarf desert. In this paper we collect all of…

Astrophysical objects below the stellar mass limit but well above the mass of Jupiter eluded discovery for nearly three decades after Kumar first proposed their existence, and for two decades after Tarter proposed the name "brown dwarfs."…

We present results from a Hubble Space Telescope imaging search for low-mass binary and planetary companions to 33 nearby brown dwarfs with spectral types of T8-Y1. Our survey provides new photometric information for these faint systems,…

A new era of directly imaged extrasolar planets has produced a three-planet system (Marois et al. 2008), where the masses of the planets have been estimated by untested cooling models. We point out that the nominal circular, face-on orbits…

The mass domain where massive extrasolar planets and brown dwarfs lay is still poorly understood. Indeed, not even a clear dividing line between massive planets and brown dwarfs has been established yet. This is partly due to the paucity of…

Stellar activity and rotation frustrate the detection of exoplanets through the radial velocity technique. This effect is particularly of concern for M dwarfs, which can remain magnetically active for billions of years. We compile rotation…

The origin of very low-mass hydrogen-burning stars, brown dwarfs, and planetary-mass objects at the low-mass end of the initial mass function is not yet fully understood. Gravitational fragmentation of circumstellar discs provides a…

Precision radial velocity (RV) measurements of the Sun-like dwarf 14 Herculis published by Naef et. al (2004), Butler et. al (2006) and Wittenmyer et al (2007) reveal a Jovian planet in a 1760 day orbit and a trend indicating the second…

Long-term instability in multi-planet exosystems is a crucial consideration when confirming putative candidates, analyzing exoplanet populations, constraining the age of exosystems, and identifying the sources of white dwarf pollution. Two…

Determining the sequence of events in the formation of stars and planetary systems and their time-scales is essential for understanding those processes, yet establishing ages is fundamentally difficult because we lack direct indicators. In…

The results of new spectroscopic analyses of 30 stars with giant planet and/or brown dwarf companions are presented. Values for Teff and [Fe/H] are used in conjunction with Hipparcos data and Padova isochrones to derive masses, ages, and…

We report the discovery of a brown dwarf on an eccentric orbit and with a semimajor axis that places it in the brown dwarf desert region around the star HD191760. The star has a spectral type of G3IV/V and a metallicity ([Fe/H]) of 0.29…

We present Herschel far-infrared and submillimeter maps of the debris disk associated with the HR 8799 planetary system. We resolve the outer disk emission at 70, 100, 160 and 250 um and detect the disk at 350 and 500 um. A smooth model…