scholarly journals Characterizing brown dwarf companions with IRDIS long-slit spectroscopy: HD 1160 B and HD 19467 B

2020 ◽  
Vol 495 (4) ◽  
pp. 4279-4290 ◽  
Author(s):  
D Mesa ◽  
V D’Orazi ◽  
A Vigan ◽  
D Kitzmann ◽  
K Heng ◽  
...  
Keyword(s):  
Spectral Type ◽  
Spectral Band ◽  
Mass Separation ◽  
Brown Dwarf ◽  
Fundamental Properties ◽  
Medium Resolution ◽  
Low Mass ◽  
Formation And Evolution ◽  
Substellar Companions ◽  
Spectral Libraries

ABSTRACT 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 substellar companions is available to date only for a limited number of objects (and mostly at very low resolution, R < 50) because of technical limitations, i.e. contrast and angular resolution. We present medium resolution (R = 350), coronagraphic long-slit spectroscopic observations with SPHERE of two substellar companions, HD 1160 B and HD 19467 B. We found that HD 1160 B has a peculiar spectrum that cannot be fitted by spectra in current spectral libraries. A good fit is possible only considering separately the Y+J and the H spectral band. The spectral type is between M5 and M7. We also estimated a Teff of 2800–2900 K and a log g of 3.5–4.0 dex. The low surface gravity seems to favour young age (10–20 Myr) and low mass (∼20 MJup ) for this object. HD 19467 B is instead a fully evolved object with a Teff of ∼1000 K and log g of ∼5.0 dex. Its spectral type is T6 ± 1.

scholarly journals Brown Dwarf Binaries

2011 ◽  
Vol 7 (S282) ◽  
pp. 105-110 ◽  
Author(s):  
Katelyn N. Allers
Keyword(s):  
Brown Dwarfs ◽  
Theoretical Models ◽  
Solar Neighborhood ◽  
Test Model ◽  
Brown Dwarf ◽  
Fundamental Properties ◽  
Model Predictions ◽  
Low Mass ◽  
Formation And Evolution ◽  
Insight Into

AbstractNearly 500 brown dwarfs have been discovered in recent years. The majority of these brown dwarfs exist in the solar neighborhood, yet determining their fundamental properties (mass, age, temperature & metallicity) has proved to be quite difficult, with current estimates relying heavily on theoretical models. Binary brown dwarfs provide a unique opportunity to empirically determine fundamental properties, which can then be used to test model predictions. In addition, the observed binary fractions, separations, mass ratios, & orbital eccentricities can provide insight into the formation mechanism of these low-mass objects. I will review the results of various brown dwarf multiplicity studies, and will discuss what we have learned about the formation and evolution of brown dwarfs by examining their binary properties as a function of age and mass.

scholarly journals FURTHER DEFINING SPECTRAL TYPE “Y” AND EXPLORING THE LOW-MASS END OF THE FIELD BROWN DWARF MASS FUNCTION

2012 ◽  
Vol 753 (2) ◽  
pp. 156 ◽  
Author(s):  
J. Davy Kirkpatrick ◽  
Christopher R. Gelino ◽  
Michael C. Cushing ◽  
Gregory N. Mace ◽  
Roger L. Griffith ◽  
...  
Keyword(s):  
Spectral Type ◽  
Mass Function ◽  
Brown Dwarf ◽  
Low Mass

scholarly journals Discovery of a brown dwarf companion to the star HIP 64892

2018 ◽  
Vol 615 ◽  
pp. A160 ◽  
Author(s):  
A. Cheetham ◽  
M. Bonnefoy ◽  
S. Desidera ◽  
M. Langlois ◽  
A. Vigan ◽  
...  
Keyword(s):  
Spectral Energy Distribution ◽  
Angular Separation ◽  
Dual Band ◽  
Spectral Energy ◽  
Mass Ratio ◽  
Atmospheric Models ◽  
Brown Dwarf ◽  
Low Mass ◽  
Formation And Evolution ◽  
Projected Distance

We report the discovery of a bright, brown dwarf companion to the star HIP 64892, imaged with VLT/SPHERE during the SHINE exoplanet survey. The host is a B9.5V member of the Lower-Centaurus-Crux subgroup of the Scorpius Centaurus OB association. The measured angular separation of the companion (1.2705 ± 0.0023”) corresponds to a projected distance of 159 ± 12 AU. We observed the target with the dual-band imaging and long-slit spectroscopy modes of the IRDIS imager to obtain its spectral energy distribution (SED) and astrometry. In addition, we reprocessed archival NACO L-band data, from which we also recover the companion. Its SED is consistent with a young (<30 Myr), low surface gravity object with a spectral type of M9γ ± 1. From comparison with the BT-Settl atmospheric models we estimate an effective temperature of Teff = 2600 ± 100 K, and comparison of the companion photometry to the COND evolutionary models yields a mass of ~29−37 MJ at the estimated age of 16−7+15 Myr for the system. The star HIP 64892 is a rare example of an extreme-mass ratio system (q ~ 0.01) and will be useful for testing models relating to the formation and evolution of such low-mass objects.

scholarly journals Discovery of a Tight Brown Dwarf Companion to the Low Mass Star LHS 2397a

2003 ◽  
Vol 211 ◽  
pp. 261-264 ◽  
Author(s):  
Melanie Freed ◽  
Laird M. Close ◽  
Nick Siegler
Keyword(s):  
Adaptive Optics ◽  
Spectral Type ◽  
Proper Motion ◽  
Near Infrared ◽  
Mass Star ◽  
Infrared Photometry ◽  
Brown Dwarf ◽  
Dynamical Mass ◽  
Low Mass ◽  
Adaptive Optics System

Using the adaptive optics system, Hōkūpa'a, at Gemini-North, we have directly imaged a companion around the UKIRT faint standard M8 star, LHS 2397a (FS 129) at a separation of 2.96 AU. Near-Infrared photometry obtained on the companion has shown it to be an L7.5 brown dwarf and confirmed the spectral type of the primary to be an M8. We also derive a substellar mass of the companion of 0.068M⊙, although masses in the range (0.061 – 0.069) are possible, and the primary mass as 0.090M⊙ (0.089 – 0.094). Reanalysis of archival imaging from HST has confirmed the secondary as a common proper motion object. This binary represents the first clear example of a brown dwarf companion within 4 AU of a low mass star, and should be the first L7.5 to have a dynamical mass. As part of a larger survey of M8-M9 stars, this object may indicate that there is no “brown dwarf desert” around low mass primaries.

scholarly journals VERY LOW MASS STELLAR AND SUBSTELLAR COMPANIONS TO SOLAR-LIKE STARS FROM MARVELS. V. A LOW ECCENTRICITY BROWN DWARF FROM THE DRIEST PART OF THE DESERT, MARVELS-6b

2013 ◽  
Vol 145 (6) ◽  
pp. 155 ◽  
Author(s):  
Nathan De Lee ◽  
Jian Ge ◽  
Justin R. Crepp ◽  
Jason Eastman ◽  
Massimiliano Esposito ◽  
...  
Keyword(s):  
Brown Dwarf ◽  
Low Mass ◽  
Substellar Companions

scholarly journals VERY-LOW-MASS STELLAR AND SUBSTELLAR COMPANIONS TO SOLAR-LIKE STARS FROM MARVELS. III. A SHORT-PERIOD BROWN DWARF CANDIDATE AROUND AN ACTIVE G0IV SUBGIANT

2012 ◽  
Vol 145 (1) ◽  
pp. 20 ◽  
Author(s):  
Bo Ma ◽  
Jian Ge ◽  
Rory Barnes ◽  
Justin R. Crepp ◽  
Nathan De Lee ◽  
...  
Keyword(s):  
Brown Dwarf ◽  
Short Period ◽  
Low Mass ◽  
Substellar Companions

scholarly journals VERY LOW MASS STELLAR AND SUBSTELLAR COMPANIONS TO SOLAR-LIKE STARS FROM MARVELS. IV. A CANDIDATE BROWN DWARF OR LOW-MASS STELLAR COMPANION TO HIP 67526

2013 ◽  
Vol 146 (3) ◽  
pp. 65 ◽  
Author(s):  
Peng Jiang ◽  
Jian Ge ◽  
Phillip Cargile ◽  
Justin R. Crepp ◽  
Nathan De Lee ◽  
...  
Keyword(s):  
Brown Dwarf ◽  
Low Mass ◽  
Substellar Companions

scholarly journals WD1032 + 011, an inflated brown dwarf in an old eclipsing binary with a white dwarf

2020 ◽  
Vol 497 (3) ◽  
pp. 3571-3580 ◽  
Author(s):  
S L Casewell ◽  
C Belardi ◽  
S G Parsons ◽  
S P Littlefair ◽  
I P Braker ◽  
...  
Keyword(s):  
Spectral Type ◽  
White Dwarf ◽  
Light Curves ◽  
Brown Dwarf ◽  
Eclipsing Binary ◽  
The Third ◽  
Thick Disc ◽  
Low Mass ◽  
High Cadence

ABSTRACT We present the discovery of only the third brown dwarf known to eclipse a non-accreting white dwarf. Gaia parallax information and multicolour photometry confirm that the white dwarf is cool (9950 ± 150 K) and has a low mass (0.45 ± 0.05 M⊙), and spectra and light curves suggest the brown dwarf has a mass of 0.067 ± 0.006 M⊙ (70MJup) and a spectral type of L5 ± 1. The kinematics of the system show that the binary is likely to be a member of the thick disc and therefore at least 5-Gyr old. The high-cadence light curves show that the brown dwarf is inflated, making it the first brown dwarf in an eclipsing white dwarf-brown dwarf binary to be so.

scholarly journals Orbiting a binary

2017 ◽  
Vol 608 ◽  
pp. A106 ◽  
Author(s):  
M. Bonavita ◽  
V. D’Orazi ◽  
D. Mesa ◽  
C. Fontanive ◽  
S. Desidera ◽  
...  
Keyword(s):  
Near Infrared ◽  
Speckle Pattern ◽  
Major Axis ◽  
Brown Dwarf ◽  
Semi Major Axis ◽  
Similar Frequency ◽  
Link Type ◽  
Medium Resolution ◽  
Low Mass ◽  
Imaging Mode

Aims. In this paper we present the results of the SPHERE observation of the HD 284149 system, aimed at a more detailed characterisation of both the primary and its brown dwarf companion. Methods. We observed HD 284149 in the near-infrared with SPHERE, using the imaging mode (IRDIS+IFS) and the long-slit spectroscopy mode (IRDIS-LSS). The data were reduced using the dedicated SPHERE pipeline, and algorithms such as PCA and TLOCI were applied to reduce the speckle pattern. Results. The IFS images revealed a previously unknown low-mass (~0.16 M⊙) stellar companion (HD 294149 B) at ~0.1′′, compatible with previously observed radial velocity differences, as well as proper motion differences between Gaia and Tycho-2 measurements. The known brown dwarf companion (HD 284149 b) is clearly visible in the IRDIS images. This allowed us to refine both its photometry and astrometry. The analysis of the medium resolution IRDIS long slit spectra also allowed a refinement of temperature and spectral type estimates. A full reassessment of the age and distance of the system was also performed, leading to more precise values of both mass and semi-major axis. Conclusions. As a result of this study, HD 284149 ABb therefore becomes the latest addition to the (short) list of brown dwarfs on wide circumbinary orbits, providing new evidence to support recent claims that object in such configuration occur with a similar frequency to wide companions to single stars.

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