OGLE-2017-BLG-1522: A Giant Planet around a Brown Dwarf Located in the Galactic Bulge

Planet formation theories predict the existence of free-floating planets that have been ejected from their parent systems. Although they emit little or no light, they can be detected during gravitational microlensing events. Microlensing events caused by rogue planets are characterized by very short timescales tE (typically below two days) and small angular Einstein radii θE (up to several μas). Here we present the discovery and characterization of two ultra-short microlensing events identified in data from the Optical Gravitational Lensing Experiment (OGLE) survey, which may have been caused by free-floating or wide-orbit planets. OGLE-2012-BLG-1323 is one of the shortest events discovered thus far (tE = 0.155 ± 0.005 d, θE = 2.37 ± 0.10μas) and was caused by an Earth-mass object in the Galactic disk or a Neptune-mass planet in the Galactic bulge. OGLE-2017-BLG-0560 (tE = 0.905 ± 0.005 d, θE = 38.7 ± 1.6μas) was caused by a Jupiter-mass planet in the Galactic disk or a brown dwarf in the bulge. We rule out stellar companions up to a distance of 6.0 and 3.9 au, respectively. We suggest that the lensing objects, whether located on very wide orbits or free-floating, may originate from the same physical mechanism. Although the sample of ultrashort microlensing events is small, these detections are consistent with low-mass wide-orbit or unbound planets being more common than stars in the Milky Way.

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Two bodies with high eccentricity around the cataclysmic variable QS Vir

Proceedings of the International Astronomical Union ◽

10.1017/s1743921311020941 ◽

2010 ◽

Vol 6 (S276) ◽

pp. 495-496 ◽

Cited By ~ 5

Author(s):

Leonardo A. Almeida ◽

Francisco Jablonski

Keyword(s):

Orbital Period ◽

Giant Planet ◽

Cataclysmic Variable ◽

Brown Dwarf ◽

Period Variations ◽

Angular Momentum Loss ◽

Best Fitting ◽

Orbital Periods ◽

The Masses ◽

Two Bodies

AbstractQS Vir is an eclipsing cataclysmic variable with 3.618 hrs orbital period. This system has the interesting characteristics that it does not show mass transfer between the components through the L1 Lagrangian point and shows a complex orbital period variation history. Qian et al. (2010) associated the orbital period variations to the presence of a giant planet in the system plus angular momentum loss via magnetic braking. Parsons et al. (2010) obtained new eclipse timings and observed that the orbital period variations associated to a hypothetical giant planet disagree with their measurements and concluded that the decrease in orbital period is part of a cyclic variation with period ~16 yrs. In this work, we present 28 new eclipse timings of QS Vir and suggest that the orbital period variations can be explained by a model with two circumbinary bodies. The best fitting gives the lower limit to the masses M1 sin(i) ~ 0.0086 M⊙ and M2 sin(i) ~ 0.054 M⊙; orbital periods P1 ~ 14.4 yrs and P2 ~ 16.99 yrs, and eccentricities e1 ~ 0.62 and e2~0.92 for the two external bodies. Under the assumption of coplanarity among the two external bodies and the inner binary, we obtain a giant planet with ~0.009 M⊙ and a brown dwarf with ~ 0.056 M⊙ around the eclipsing binary QS Vir.

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Direct imaging of an ultracool substellar companion to the exoplanet host star HD 4113 A

Astronomy and Astrophysics ◽

10.1051/0004-6361/201630136 ◽

2018 ◽

Vol 614 ◽

pp. A16 ◽

Cited By ~ 16

Author(s):

A. Cheetham ◽

D. Ségransan ◽

S. Peretti ◽

J.-B. Delisle ◽

J. Hagelberg ◽

...

Keyword(s):

Giant Planet ◽

Radial Velocities ◽

Physical Parameters ◽

Imaging Data ◽

Brown Dwarf ◽

Contrast Imaging ◽

Direct Imaging ◽

Dynamical Mass ◽

Methane Absorption ◽

Mass Estimate

Using high-contrast imaging with the SPHERE instrument at the Very Large Telescope (VLT), we report the first images of a cold brown dwarf companion to the exoplanet host star HD 4113A. The brown dwarf HD 4113C is part of a complex dynamical system consisting of a giant planet, a stellar host, and a known wide M-dwarf companion. Its separation of 535 ± 3 mas and H-band contrast of 13.35 ± 0.10 mag correspond to a projected separation of 22 AU and an isochronal mass estimate of 36 ± 5 MJ based on COND models. The companion shows strong methane absorption, and through fitting an atmosphere model, we estimate a surface gravity of logg = 5 and an effective temperature of ~500–600 K. A comparison of its spectrum with observed T dwarfs indicates a late-T spectral type, with a T9 object providing the best match. By combining the observed astrometry from the imaging data with 27 years of radial velocities, we use orbital fitting to constrain its orbital and physical parameters, as well as update those of the planet HD 4113A b, discovered by previous radial velocity measurements. The data suggest a dynamical mass of 66−4+5 MJ and moderate eccentricity of 0.44−0.07+0.08 for the brown dwarf. This mass estimate appears to contradict the isochronal estimate and that of objects with similar temperatures, which may be caused by the newly detected object being an unresolved binary brown dwarf system or the presence of an additional object in the system. Through dynamical simulations, we show that the planet may undergo strong Lidov-Kozai cycles, raising the possibility that it formed on a quasi-circular orbit and gained its currently observed high eccentricity (e ~ 0.9) through interactions with the brown dwarf. Follow-up observations combining radial velocities, direct imaging, and Gaia astrometry will be crucial to precisely constrain the dynamical mass of the brown dwarf and allow for an in-depth comparison with evolutionary and atmosphere models.

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A giant planet candidate near a young brown dwarf

Astronomy and Astrophysics ◽

10.1051/0004-6361:200400056 ◽

2004 ◽

Vol 425 (2) ◽

pp. L29-L32 ◽

Cited By ~ 413

Author(s):

G. Chauvin ◽

A.-M. Lagrange ◽

C. Dumas ◽

B. Zuckerman ◽

D. Mouillet ◽

...

Keyword(s):

Giant Planet ◽

Brown Dwarf

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VERY LOW-MASS STELLAR AND SUBSTELLAR COMPANIONS TO SOLAR-LIKE STARS FROM MARVELS. VI. A GIANT PLANET AND A BROWN DWARF CANDIDATE IN A CLOSE BINARY SYSTEM HD 87646

The Astronomical Journal ◽

10.3847/0004-6256/152/5/112 ◽

2016 ◽

Vol 152 (5) ◽

pp. 112 ◽

Cited By ~ 10

Author(s):

Bo Ma(馬波) ◽

Jian Ge ◽

Alex Wolszczan ◽

Matthew W. Muterspaugh ◽

Brian Lee ◽

...

Keyword(s):

Binary System ◽

Giant Planet ◽

Close Binary System ◽

Close Binary ◽

Brown Dwarf ◽

Low Mass ◽

Substellar Companions

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Microlensing Constraints on Low-Mass Companions

Symposium - International Astronomical Union ◽

10.1017/s0074180900210826 ◽

2003 ◽

Vol 211 ◽

pp. 305-308

Author(s):

B. Scott Gaudi

Keyword(s):

Detailed Analysis ◽

Quality Data ◽

Brute Force ◽

Galactic Bulge ◽

Force Analysis ◽

Brown Dwarf ◽

M Dwarfs ◽

Survey Quality ◽

Low Mass

Microlensing is sensitive to binary, brown dwarf (BD), and planetary companions to normal stars in the Galactic bulge with separations between about 1–10 AU. The accurate, densely-sampled photometry of microlensing events needed to detect planetary companions has been achieved by several follow-up collaborations. Detailed analysis of microlensing events toward the bulge demonstrates that less than 45% of M-dwarfs in the bulge have MJup companions between 1 and 5 AU. Detection of binary and BD companions using microlensing is considerably easier; however, the interpretation is hampered by their non-perturbative influence on the parent lightcurve. I demonstrate that ~ 25% of BD companions with separations 1 – 10AU should be detectable with survey-quality data (~ 1 day sampling and ~ 5% photometry). Survey data is more amenable to generic, brute-force analysis methods and less prone to selection biases. An analysis of the ~ 1500 microlensing events detected by OGLE-III in the next three years should test whether the BD desert exists at separations 1 – 10AU from M-dwarfs in the Galactic bulge.

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The Role of Clouds in Brown Dwarf and Extrasolar Giant Planet Atmospheres

Symposium - International Astronomical Union ◽

10.1017/s0074180900218044 ◽

2004 ◽

Vol 202 ◽

pp. 269-276

Author(s):

Mark S. Marley ◽

Andrew S. Ackerman

Keyword(s):

Remote Sensing ◽

Solar System ◽

Direct Detection ◽

Giant Planet ◽

Brown Dwarfs ◽

Giant Planets ◽

Brown Dwarf ◽

L Dwarfs ◽

Extrasolar Giant Planet

Clouds and hazes are important throughout our solar system and in the atmospheres of brown dwarfs and extrasolar giant planets. Among the brown dwarfs, clouds control the colors and spectra of the L-dwarfs; the disappearance of clouds helps herald the arrival of the T-dwarfs. The structure and composition of clouds will be among the first remote-sensing results from the direct detection of extrasolar giant planets.

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Glittery clouds in exoplanetary atmospheres?

International Journal of Astrobiology ◽

10.1017/s1473550408004382 ◽

2009 ◽

Vol 8 (1) ◽

pp. 3-8 ◽

Cited By ~ 15

Author(s):

Ch. Helling ◽

F.J.M. Rietmeijer

Keyword(s):

Gas Phase ◽

Lattice Structure ◽

Giant Planet ◽

Amorphous State ◽

Material Composition ◽

Cloud Formation ◽

Brown Dwarf ◽

Seed Formation ◽

Grain Sizes ◽

Exoplanetary Atmospheres

AbstractCloud formation modelling has entered astrophysics as a new field of research for planetary and brown dwarf atmospheres. Clouds are a chemically and physically very active component of an atmosphere since they determine the remaining gas phase and change the object's albedo depending on their material composition. The grains can also provide a surface where the molecular constituents for life can be physisorbed for possible pre-biotic evolution. This paper summarizes our model for the kinetic formation of dirty dust grains which make up the atmospheric clouds of extraterrestrial giant gas planets. We include seed formation, surface growth and evaporation, the gravitational settling that influences the dust formation, element depletion that determines the remaining gas phase abundances, and convective overshooting that is needed for a dust model to be applicable to hydrostatic atmosphere simulations. We demonstrate the evolution of the material composition of the cloud itself and the distribution of the grain sizes in the cloud layer, exemplary for a giant gas planet parameter combinations (Teff, log g). In general, substellar clouds are composed of small, dirty grains with a high silicate content at the cloud deck. They grow in size and gradually purify to iron/corundum grains when they move into denser and hotter atmospheric regions. Comparing these results with experimental data from condensation experiments leads to the conclusion that cloud grains that gravitationally settle in the atmosphere of a giant planet can easily change their lattice structure from the disordered amorphous state they are forming in, into the ordered lattice of a crystal.

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