Citation for published item:uonopkyD uinn wF nd meuD tulien nd huh¢ eneD qsprd nd pilippzzoD toseph gF nd qiorl qodfreyD ige eF nd wroisD ghristin nd xielsenD iri vF nd ueyoD vurent nd (kovD omn F nd ieD imily vF nd ngD tson tF nd emmonsD F wrk nd fileyD ness F nd frmnD rvis F nd fulgerD tonn nd fruzzoneD estin nd ghiloteD te'rey uF nd gottenD r nd hwsonD eekh sF nd he osD oert tF nd hoyonD en¡ e nd ispositoD homs wF nd pitzgerldD wihel F nd polletteD utherine fF nd qoodsellD tephen nd qrhmD tmes F nd qreenumD elexndr F nd rionD sle nd rungD viEei nd sngrhmD trik nd ulsD ul nd vfreni ereD hvid nd vrkinD tmes iF nd wintoshD frue eF nd wireD t¡ er¢ ome nd wrhisD prnk nd wrleyD wrk F nd wtthewsD frend gF nd wethevD tnimir nd willrEflnherD wxwell eF nd yppenheimerD ee nd lmerD hvid F nd tieneD tenny nd errinD wrshll hF nd oyneerD vis eF nd jnD ehijith nd ntkyr¤ oD predrik F nd vrnskyD hmitry nd hneiderD edm gF nd ivrmkrishnnD ennd nd ongD snseok nd oummerD emi nd homsD ndrine nd lleD tF uent nd rdEhuongD uimerly nd iktorowizD lone tF nd ol'D huyler qF @PHITA 9hisovery of sustellr ompnion to the nery deris disk host r PSTPF9D estrophysil journl lettersFD VPW @IAF vRF Further information on publisher's website: Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. ABSTRACTWe present the discovery of a brown dwarf companion to the debris disk host star HR 2562. This object, discovered with the Gemini Planet Imager (GPI), has a projected separation of 20.3±0.3 au (    0. 618 0. 004) from the star. With the high astrometric precision afforded by GPI, we have confirmed, to more than 5σ, the common proper motion of HR 2562B with the star, with only a month-long time baseline between observations. Spectral data in the J-, H-, and K-bands show a morphological similarity to L/T transition objects. We assign a spectral type of L7±3 to HR 2562Band derive a luminosity of log(, corresponding to a mass of 30±15 M Jup from evolutionary models at an estimated age of the system of 300-900 Myr. Although the uncertainty in the age of the host star is significant, the spectra and photometry exhibit several indications of youth for HR 2562B. The source has a position angle that is consistent with an orbit in the same plane as the debris disk recently resolved with Herschel. Additionally, it appears to be interior to the debris disk. Though the extent of the inner hole is currently too uncertain to place limits on the mass of HR 2562B, future observations of the disk with higher spatial resolution may be able to provide m...

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 of substellar objects. The TRENDS highcontrast imaging survey has recently discovered a (mass/age/metallicity) benchmark brown dwarf orbiting the nearby (d = 18.69 ± 0.19 pc), G8V/K0V star HD 4747. We have acquired follow-up spectroscopic measurements of HD 4747 B using the Gemini Planet Imager to study its spectral type, effective temperature, surface gravity, and cloud properties. Observations obtained in the H-band and K 1 -band recover the companion and reveal that it is near the L/T transition (T1±2). Fitting atmospheric models to the companion spectrum, we find strong evidence for the presence of clouds. However, spectral models cannot satisfactorily fit the complete data set: while the shape of the spectrum can be well-matched in individual filters, a joint fit across the full passband results in discrepancies that are a consequence of the inherent color of the brown dwarf. We also find a 2σ tension in the companion mass, age, and surface gravity when comparing to evolutionary models. These results highlight the importance of using benchmark objects to study "secondary effects" such as metallicity, non-equilibrium chemistry, cloud parameters, electron conduction, non-adiabatic cooling, and other subtleties affecting emergent spectra. As a new L/T transition benchmark, HD 4747 B warrants further investigation into the modeling of cloud physics using higher resolution spectroscopy across a broader range of wavelengths, polarimetric observations, and continued Doppler radial velocity and astrometric monitoring.