Spectral and atmospheric characterisation of a new benchmark brown dwarf HD 13724 B

Rickman, E. L.; Ségransan, D.; Hagelberg, J.; Beuzit, J. L.; Cheetham, A.; Delisle, J.-B.; Forveille, T.; Udry, S.

doi:10.1051/0004-6361/202037524

Cited by 23 publications

(31 citation statements)

References 53 publications

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“…However, uncertainties in the age estimates and in the initial conditions during the forma-angular separation to the star of ∼1.65 , corresponding to a projected separation of ∼53 au, a flux ratio with respect to the star ∆K s = 12.57 ± 0.09 mag, with blue J-H and J-K s colors, as well as a minimum dynamical mass of 51.9 +3.6 −4.3 M J inferred from the RV acceleration and the projected separation (assuming a distance of 30.86 ± 0.60 pc from HIPPARCOS, van Leeuwen 2007). It is part of a growing group of imaged brown dwarfs of spectral type T with an RV signature, which includes, GJ 758B (Thalmann et al 2009;Bowler et al 2018), HD 4113C (Cheetham et al 2018), GJ 229B (Nakajima et al 1995;Brandt et al 2019a), and HD 13724B (Rickman et al 2020). Such objects are valuable benchmarks for atmospheric and evolutionary models of cool substellar objects.…”

Section: Introductionmentioning

confidence: 99%

Orbital and spectral characterization of the benchmark T-type brown dwarf HD 19467B

Maire

Molaverdikhani

Desidera

et al. 2020

A&A

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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 mechanisms. HD 19467 is a bright and nearby star hosting a cool brown dwarf companion detected with radial velocities and imaging, making it a valuable object for such studies. Aims. We aim to further characterize the orbital, spectral, and physical properties of the HD 19467 system. Methods. We present new high-contrast imaging data with the SPHERE and NaCo instruments. We also analyze archival data from the instruments HARPS, NaCo, HIRES, UVES, and ASAS. Furthermore, we use proper motion data of the star from HIPPARCOS and Gaia. Results. We refined the properties of the host star and derived an age of 8.0+2.0−1.0 Gyr based on isochrones, gyrochronology, and chemical and kinematic arguments. This age estimate is slightly younger than previous age estimates of ~9–11 Gyr based on isochrones. No orbital curvature is seen in the current imaging, radial velocity, and astrometric data. From a joint fit of the data, we refined the orbital parameters for HD 19467B, including: a period of 398+95−93 yr, an inclination of 129.8+8.1−5.1 deg, an eccentricity of 0.56 ± 0.09, a longitude of the ascending node of 134.8 ± 4.5 deg, and an argument of the periastron of 64.2+5.5−6.3 deg. We assess a dynamical mass of 74+12−9 MJ. The fit with atmospheric models of the spectrophotometric data of the companion indicates an atmosphere without clouds or with very thin clouds, an effective temperature of 1042+77−71 K, and a high surface gravity of 5.34+0.8−0.9 dex. The comparison to model predictions of the bolometric luminosity and dynamical mass of HD 19467B, assuming our system age estimate, indicates a better agreement with the Burrows et al. (1997, ApJ, 491, 856) models; whereas, the other evolutionary models used tend to underestimate its cooling rate.

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Section: Introductionmentioning

confidence: 99%

Orbital and spectral characterization of the benchmark T-type brown dwarf HD 19467B

Maire

Molaverdikhani

Desidera

et al. 2020

A&A

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“…Currently, only a handful of BD companions has been spectroscopically investigated exploiting the limited resolution (R ∼ 30-50) of integral-field spectrograph such as SPHERE and GPI. Some examples include HR 2562 B (Konopacky et al 2016;Mesa et al 2018), HD 984 B (Johnson-Groh et al 2017), HD 1160 B (Maire et al 2016;Garcia et al 2017), HD 206893 B (Delorme et al 2017), HD 4747 B (Crepp et al 2018;Peretti et al 2019), and HD 13724 B (Rickman et al 2020). In only five more cases, it was possible to obtain a spectrum with a larger resolution (R = 350), using the SPHERE long-slit spectroscopy (LSS; Vigan et al 2008) observing mode.…”

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

Mesa

D’Orazi

Vigan

et al. 2020

Monthly Notices of the Royal Astronomical Society

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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.

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“…We rely on unsaturated non-coronagraphic exposures with both stars in the field-of-view to calibrate the photometry, the PSF profile, and the astrometric configuration of the targeted binary system. The last part of the calibration sequence are the star centring frames where satellite spots are generated through a sinusoidal pattern on the deformable mirror (Jovanovic et al 2015;Rickman et al 2020) in order to determine precisely the position of the primary star behind the coronagraph. Typically the total observing time dedicated to each target is an hour, which besides the 15 minutes spent on telescope slewing and target acquisition is split in 80/20% between the science observation and calibrations.…”

Section: Observational Strategymentioning

confidence: 99%

VIBES: Visual Binary Exoplanet survey with SPHERE

Hagelberg

Engler

Fontanive

et al. 2020

A&A

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Context. Recent surveys indicate that planets in binary systems are more abundant than previously thought, which is in agreement with theoretical work on disc dynamics and planet formation in binaries. So far, most observational surveys, however, have focused on short-period planets in binaries, thus little is known about the occurrence rates of planets on longer periods (≥10 au). Aims. In order to measure the abundance and physical characteristics of wide-orbit giant exoplanets in binary systems, we have designed the “VIsual Binary Exoplanet survey with Sphere” (VIBES) to search for planets in visual binaries. It uses the SPHERE instrument at VLT to search for planets in 23 visual binary and four visual triple systems with ages of <145 Myr and distances of <150 pc. Methods. We used the IRDIS dual-band imager on SPHERE to acquire high-contrast images of the sample targets. For each binary, the two components were observed at the same time with a coronagraph masking only the primary star. For the triple star, the tight components were treated as a single star for data reduction. This enabled us to effectively search for companions around 50 individual stars in binaries and four binaries in triples. Results. We derived upper limits of <13.7% for the frequency of sub-stellar companions around primaries in visual binaries, <26.5% for the fraction of sub-stellar companions around secondaries in visual binaries, and an occurrence rate of <9.0% for giant planets and brown dwarfs around either component of visual binaries. We have combined our observations with literature measurements to astrometrically confirm, for the first time, that 20 binaries and two triple systems, which were previously known, are indeed physically bound. Finally, we discovered a third component of the binary HD 121336. Conclusions. The upper limits we derived are compatible with planet formation through the core accretion and the gravitational instability processes in binaries. These limits are also in line with limits found for single star and circumbinary planet search surveys.

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Spectral and atmospheric characterisation of a new benchmark brown dwarf HD 13724 B

Cited by 23 publications

References 53 publications

Orbital and spectral characterization of the benchmark T-type brown dwarf HD 19467B

Orbital and spectral characterization of the benchmark T-type brown dwarf HD 19467B

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

VIBES: Visual Binary Exoplanet survey with SPHERE

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