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Related papers: New brown dwarf disks in Upper Scorpius observed w…

200 papers

We are conducting a U,B,R,I monitoring program to identify pre-main sequence stars and brown dwarfs in a 12.5x12.2 square degree region of the Upper Scorpius OB association (5-10 Myr). We will use these data in combination with a follow-up…

Astrophysics · Physics 2007-05-23 C. L. Slesnick , J. M. Carpenter , L. A. Hillenbrand

The time evolution of the dependence of the mass accretion rate with the stellar mass and the disk mass represents a fundamental way to understand the evolution of protoplanetary disks and the formation of planets. In this work, we present…

Solar and Stellar Astrophysics · Physics 2024-02-19 V. Almendros-Abad , C. F. Manara , L. Testi , A. Natta , R. A. B. Claes , K. Muzic , E. Sanchis , J. M. Alcalá , A. Bayo , A. Scholz

We have performed a census of disks around brown dwarfs in the Sigma Ori cluster using all available images from IRAC onboard the Spitzer Space Telescope. To search for new low-mass cluster members with disks, we have measured photometry…

Astrophysics · Physics 2008-12-18 K. L. Luhman , J. Hernandez , J. J. Downes , L. Hartmann , C. Briceno

In our analysis of {\it Spitzer}/IRS archival data on the stellar and sub-stellar members of the TW Hydrae Association (TWA), we have discovered two new brown dwarf disks: a flat optically thick disk around SSSPM J1102-3431 (SSSPM 1102),…

Astrophysics · Physics 2009-11-13 B. Riaz , J. E. Gizis

While brown dwarfs show similarities with stars in their early life, their spin evolution is much more akin to that of planets. We have used lightcurves from the K2 mission to measure new rotation periods for 18 young brown dwarfs in the…

Earth and Planetary Astrophysics · Physics 2018-06-27 Aleks Scholz , Keavin Moore , Ray Jayawardhana , Suzanne Aigrain , Dawn Peterson , Beate Stelzer

The Upper-Scorpius association (5-11 Myr) contains a unique population of low-mass (M<30 MJup) brown-dwarfs. The detailed relative characterization of their physical properties (mass, radius, temperature, composition, ongoing accretion)…

Recent surveys have identified sub-stellar objects down to planetary masses in nearby star-forming regions. Reliable determination of the disk frequency in young brown dwarfs is of paramount importance to understanding their origin. Here we…

Astrophysics · Physics 2016-08-30 Ray Jayawardhana , David R. Ardila , Beate Stelzer , Karl E. Haisch

(Abridged) We have completed the first systematic survey for disks around spectroscopically identified young brown dwarfs and very low mass stars. We have obtained L'-band (3.8 um) imaging for 38 very cool objects in IC 348 and Taurus. Our…

Astrophysics · Physics 2008-11-26 Michael C. Liu , Joan Najita , Alan T. Tokunaga

We have imaged two bona-fide brown dwarfs with TReCS/GEMINI-S and find mid-infrared excess emission that can be explained by optically thick dust disk models. In the case of the young ($\approx$2Myr) Cha H$\alpha$1 we measure fluxes at…

We present a study of 15 new brown dwarfs belonging to the $\sim7$ Myr old 25 Orionis group and Orion OB1a sub-association with spectral types between M6 and M9 and estimated masses between $\sim0.07$M$_\odot$ and $\sim0.01$ M$_\odot$. By…

We have carried out sensitive 1.3 mm observations of 20 young brown dwarfs in the Taurus star-forming region, representing the largest sample of young substellar objects targeted in a deep millimeter continuum survey to date. Under standard…

Astrophysics · Physics 2009-11-11 Alexander Scholz , Ray Jayawardhana , Kenneth Wood

We have refined the census of stars and brown dwarfs in the Upper Sco association (~10 Myr, ~145 pc) by 1) updating the selection of candidate members from our previous survey to include the high-precision astrometry from the second data…

Solar and Stellar Astrophysics · Physics 2020-07-08 K. L. Luhman , T. L. Esplin

We report new Spitzer Space Telescope observations from the IRAC and MIPS instruments of the young (~ 3 Myr) sigma Orionis cluster. We identify 336 stars as members of the cluster using optical and near-infrared color magnitude diagrams.…

This review summarises recent observational results regarding the evolution of angular momentum and disks in brown dwarfs. The observations clearly show that brown dwarfs beyond ages of 10 Myr are exclusively fast rotators and do not spin…

Solar and Stellar Astrophysics · Physics 2013-06-25 Aleks Scholz

We present low-resolution (R=900) optical (576.1--1,051.1 nm) spectroscopic observations of 40 candidate very low-mass members in the Upper Scorpius OB association. These objects were selected using the $I$, $J$ and $K$ photometry available…

Astrophysics · Physics 2009-11-10 Eduardo L. Martin , Xavier Delfosse , Sylvain Guieu

We combine published optical and near-infrared photometry to identify new low-mass candidate members in an area of about 0.64 deg^2 in Corona Australis, using the S-parameter method. Five new candidate members of the region are selected,…

We present the results of a survey for stellar and substellar companions to 82 young stars in the nearby OB association Upper Scorpius. This survey used nonredundant aperture-mask interferometry to achieve typical contrast limits of…

Astrophysics · Physics 2009-11-13 Adam L. Kraus , Michael J. Ireland , Frantz Martinache , James P. Lloyd

We report on the analysis of 2MASS near-infrared data of a sample of low-mass stars and brown dwarfs in the sigma Orionis cluster. Youth and cluster membership have been spectroscopically confirmed using the Li I spectral line. We find…

Astrophysics · Physics 2009-11-07 J. M. Oliveira , R. D. Jeffries , M. J. Kenyon , S. A. Thompson , Tim Naylor

Using SpeX at the NASA Infrared Telescope Facility and the Spitzer Infrared Spectrograph, we have obtained infrared spectra from 0.7 to 30um for three young brown dwarfs in the TW Hydra Association (~10 Myr), 2M J1207-3932, 2M J1139-3159,…

Determining the mechanisms that drive the evolution of protoplanetary disks is a necessary step to understand how planets form. Here we measured the mass accretion rate for young stellar objects at age >5 Myr, a critical test for the…