Results 1 to 10 of about 66 (62)
The Astrophysical JournalWe report the results of a spectroscopic survey of candidate T subdwarfs identified by the Backyard Worlds: Planet 9 program. Near-infrared spectra of 31 sources with red J − W2 colors and large J -band reduced proper motions show varying signatures of ...
Adam J. Burgasser +36 more
doaj +4 more sources
Exploring the Extremes: Characterizing a New Population of Old and Cold Brown Dwarfs
The Astronomical Journal, 2023 Mapping out the populations of thick disk and halo brown dwarfs is important for understanding the metallicity dependence of low-temperature atmospheres and the substellar mass function.
Aaron M. Meisner +5 more
doaj +1 more source
unTimely: a Full-sky, Time-domain unWISE Catalog
The Astronomical Journal, 2023 We present the unTimely Catalog, a deep time-domain catalog of detections based on Wide-field Infrared Survey Explorer (WISE) and NEOWISE observations spanning the 2010 through 2020 time period. Detections are extracted from “time-resolved unWISE coadds,”
Aaron M. Meisner +3 more
doaj +1 more source
In Pursuit of the Least Luminous Galaxies
Advances in Astronomy, Volume 2010, Issue 1, 2010., 2010 The dwarf galaxy companions to the Milky Way are unique cosmological laboratories. With luminosities as low as 10−7LMW, they inhabit the lowest mass dark matter halos known to host stars and are presently the most direct tracers of the distribution, mass spectrum, and clustering scale of dark matter.
Beth Willman, Regina Schulte-Ladbeck
wiley +1 more source
A Slowly Pulsating Run‐Away B Star at High Galactic Latitude Ejected From a Spiral Arm
Astronomische Nachrichten, Volume 346, Issue 5, June 2025.ABSTRACT We report the discovery of the young B6 V run‐away star LAMOST J083323.18 + 430825.4, 2.5 kpc above the Galactic plane. Its atmospheric parameters and chemical composition are determined from LAMOST spectra, indicating normal composition. Effective temperature (Teff$$ {T}_{\mathrm{eff}} $$ = 14,500$$ \mathrm{14,500} $$ K) and gravity (logg ...
Ulrich Heber +3 more
wiley +1 more source
Se-ResNet+SVM Model: An Effective Method of Searching for Hot Subdwarfs from LAMOST
The Astrophysical Journal Supplement SeriesThis paper presents a robust neural network approach for identifying hot subdwarfs. Our method leveraged the Squeeze-and-Excitation Residual Network to extract abstract features, which were combined with experience features to create hybrid features ...
Zhongding Cheng +9 more
doaj +1 more source
Metal-poor Brown Dwarf Kinematics from JWST NIRSpec Spectroscopy
The Astrophysical JournalGalactic archaeology relies on stellar kinematics and chemical abundances to identify various stellar populations and associations. With JWST, Galactic archaeology of ancient metal-poor brown dwarfs is now possible through high-sensitivity, medium ...
Chih-Chun Hsu +16 more
doaj +1 more source
The Astrophysical Journal Supplement SeriesWe design a convolutional neural network incorporating channel attention and spatial attention mechanisms to predict atmospheric parameters of hot subdwarfs.
Zhenxin Lei +6 more
doaj +1 more source
Detection of Methane in the Closest Extreme Metal-poor T Dwarf WISEA J181006.18−101000.5
The Astrophysical Journal LettersWISEA J181006.18−101000.5 (WISE1810) is the nearest metal-poor ultracool dwarf to the Sun. It has a low effective temperature and has been classified as an extreme early-T subdwarf.
Jerry J.-Y. Zhang +9 more
doaj +1 more source
UNCOVER: JWST Spectroscopy of Three Cold Brown Dwarfs at Kiloparsec-scale Distances
The Astrophysical JournalWe report JWST/NIRSpec spectra of three distant T-type brown dwarfs identified in the Ultradeep NIRSpec and NIRCam ObserVations before the Epoch of Reionization (UNCOVER) survey of the Abell 2744 lensing field.
Adam J. Burgasser +21 more
doaj +1 more source