Results 61 to 70 of about 222,937 (306)
The Astrophysical Journal, 2023 We derive the bolometric luminosities ( L _bol ) of 865 field-age and 189 young ultracool dwarfs (spectral types M6–T9, including 40 new discoveries presented here) by directly integrating flux-calibrated optical to mid-infrared (MIR) spectral energy ...
Aniket Sanghi +9 more
doaj +1 more source
Activity and Kinematics of Ultracool Dwarfs Including An Amazing Flare Observation [PDF]
Astron.J.133:2258-2273,2007, 2007 We present the activity and kinematics of a representative volume-limited (20 pc) sample of 152 late-M and L dwarfs (M7--L8) photometrically selected from the Two Micron All-Sky Survey (2MASS). Using new proper motion measurements and spectrophotometric distance estimates, we calculate tangential velocities. The sample has a mean tangential velocity of
arxiv +1 more source
A Search for Companions to L Dwarfs [PDF]
Symposium - International Astronomical Union, 2003 We present the results of two imaging surveys for companions to low-luminosity dwarfs, one with Keck to a limiting magnitude of K = 20, and the other with HST to a limiting magnitude of I = 23. No companions were found at separations of 0″.5 to 20″.0, but seven companions were found within 0″.5. Based on sub-stellar evolutionary models, we estimate the
David W. Koerner +6 more
openaire +2 more sources
Contemporaneous Observations of Hα Luminosities and Photometric Amplitudes for M Dwarfs
The Astronomical Journal, 2023 While many M dwarfs are known to have strong magnetic fields and high levels of magnetic activity, we are still unsure about the properties of their starspots and the origin of their magnetic dynamos.
Aylin García Soto +4 more
doaj +1 more source
Too Many, Too Few, or Just Right? The Predicted Number and Distribution of Milky Way Dwarf Galaxies [PDF]
, 2014 We predict the spatial distribution and number of Milky Way dwarf galaxies to be discovered in the DES and LSST surveys, by completeness correcting the observed SDSS dwarf population. We apply most massive in the past, earliest forming, and earliest infall toy models to a set of dark matter-only simulated Milky Way/M31 halo pairs from Exploring the ...
arxiv +1 more source
Brown Dwarf Companions to G-type Stars. I: Gliese 417B and Gliese 584C [PDF]
Astron.J.121:3235-3253,2001, 2001 We present astrometric and spectroscopic observations confirming that two nearby G dwarf systems (Gliese 417 = BD+36 2162 and Gliese 584AB = eta CrB AB) have a widely separated, L dwarf, substellar companion. Using age estimates of the G dwarf primaries, we estimate masses for these L dwarfs from theoretical evolutionary tracks.
arxiv +1 more source
L Dwarfs and the Substellar Mass Function [PDF]
The Astrophysical Journal, 1999 Analysis of initial observations from near-infrared sky surveys has shown that the resulting photometric catalogues, combined with far-red optical data, provide an extremely effective method of finding isolated, very low-temperature objects in the general field.
Reid, I. Neill +10 more
openaire +4 more sources
Relationship of cognitive decline with glucocerebrosidase activity and amyloid‐beta 42 in DLB and PD
Annals of Clinical and Translational Neurology, EarlyView.Abstract Objective Dementia with Lewy bodies (DLB) and Parkinson's disease (PD) share clinical, pathological, and genetic risk factors, including GBA1 and APOEε4 mutations. Biomarkers associated with the pathways of these mutations, such as glucocerebrosidase enzyme (GCase) activity and amyloid‐beta 42 (Aβ42) levels, may hold potential as predictive ...
Maria Camila Gonzalez +15 more
wiley +1 more source
A Cross-Match of 2MASS and SDSS. II. Peculiar L Dwarfs, Unresolved Binaries, and the Space Density of T Dwarf Secondaries [PDF]
, 2011 We present the completion of a program to cross-correlate the SDSS Data Release 1 and 2MASS Point Source Catalog in search for extremely red L and T dwarfs. The program was initiated by Metchev and collaborators, who presented the findings on all newly identified T dwarfs in SDSS DR1, and estimated the space density of isolated T0--T8 dwarfs in the ...
arxiv +1 more source
A search for variability in brown dwarfs and L dwarfs
, 1999 A&A in press.
Bailer-Jones, C. A. L., Mundt, R.
openaire +2 more sources