Results 11 to 20 of about 40 (37)

Deep Learning–driven Atmospheric Parameter Prediction for Hot Subdwarf Stars with Synthetic and Observed Spectra

The Astrophysical Journal Supplement Series
We design a convolutional neural network incorporating channel attention and spatial attention mechanisms to predict atmospheric parameters of hot subdwarfs.
Zhenxin Lei, Yangyang Dong, Bokai Kou, Mengqi Feng, Ke Hu, Yude Bu, Jingkun Zhao   +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 Letters
WISEA 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, Nicolas Lodieu, Eduardo L. Martín, Pascal Tremblin, María Rosa Zapatero Osorio, Víctor J. S. Béjar, Nikola Vitas, Bartosz Gauza, Yakiv V. Pavlenko, Rafael Rebolo   +9 more
doaj   +1 more source

UNCOVER: JWST Spectroscopy of Three Cold Brown Dwarfs at Kiloparsec-scale Distances

The Astrophysical Journal
We 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, Rachel Bezanson, Ivo Labbe, Gabriel Brammer, Sam E. Cutler, Lukas J. Furtak, Jenny E. Greene, Roman Gerasimov, Joel Leja, Richard Pan, Sedona H. Price, Bingjie Wang, John R. Weaver, Katherine E. Whitaker, Seiji Fujimoto, Vasily Kokorev, Pratika Dayal, Themiya Nanayakkara, Christina C. Williams, Danilo Marchesini, Adi Zitrin, Pieter van Dokkum   +21 more
doaj   +1 more source

High Proper Motion Discoveries from the UKIRT Hemisphere Survey

The Astronomical Journal
We used the third data release of the UKIRT Hemisphere Survey to locate previously unrecognized high proper motion objects. We identify a total of 127 new discoveries with total proper motions ≳300 mas yr ^−1 .
Wings Zhang, Adam C. Schneider, Thomas P. Bickle, Adam J. Burgasser, Emma Softich, Federico Marocco, Daniella Bardalez Gagliuffi, Jacqueline K. Faherty, Aaron M. Meisner, J. Davy Kirkpatrick, Marc J. Kuchner, Martin Kabatnik, Frank Kiwy, Arttu Sainio, Jörg Schümann, Karl Selg-Mann, Nikolaj Stevnbak Andersen, Bruce Baller, Paul Beaulieu, John Bell, Dan Caselden, Guillaume Colin, Alexandru Dereveanco, Christoph Frank, Konstantin Glebov, Léopold Gramaize, Leslie K. Hamlet, David W. Martin, William Pendrill, Stéphane Perlin, Andres Stenner, Christopher Tanner, Melina Thévenot, Vinod Thakur   +33 more
doaj   +1 more source

Brown Dwarf Candidates in the JADES and CEERS Extragalactic Surveys

The Astrophysical Journal
By combining the James Webb Space Telescope (JWST)/NIRCam JADES and CEERS extragalactic data sets, we have uncovered a sample of 21 T and Y brown dwarf candidates at best-fit distances between 0.1 and 4.2 kpc. These sources were selected by targeting the
Kevin N. Hainline, Jakob M. Helton, Benjamin D. Johnson, Fengwu Sun, Michael W. Topping, Jarron M. Leisenring, William M. Baker, Daniel J. Eisenstein, Ryan Hausen, Raphael E. Hviding, Jianwei Lyu, Brant Robertson, Sandro Tacchella, Christina C. Williams, Christopher N. A. Willmer, Thomas L. Roellig   +15 more
doaj   +1 more source

Observations of the Ultraviolet-bright Star III-60 in the Globular Cluster NGC 6723

The Astrophysical Journal
We have analyzed archival far-ultraviolet spectra of the UV-bright star III-60 in the globular cluster NGC 6723 obtained with the Far Ultraviolet Spectroscopic Explorer and the Cosmic Origins Spectrograph. We find that the star's photospheric parameters (
William V. Dixon
doaj   +1 more source

Parallaxes, Proper Motions, and Near-infrared Photometry for 173 L and T Dwarfs from the US Naval Observatory Infrared Astrometry Program

The Astrophysical Journal
We present near-infrared parallax and proper motion astrometry for 74 L dwarfs and 99 T dwarfs, as single objects or in binary systems, obtained with the ASTROCAM astrometric imager on the USNO, Flagstaff Station 1.55 m telescope over two observing ...
Frederick J. Vrba, Adam C. Schneider, Jeffrey A. Munn, Arne A. Henden, Christain B. Luginbuhl, Conard C. Dahn, Harry H. Guetter, Blaise J. Canzian, Trudy M. Tilleman, Scott E. Dahm, Stephen J. Williams, Justice E. Bruursema, J. Davy Kirkpatrick, Adam J. Burgasser   +13 more
doaj   +1 more source

A New Route to Massive Hot Subdwarfs: Common Envelope Ejection from Asymptotic Giant Branch Stars

The Astrophysical Journal
The hot subdwarf O/B stars (sdO/Bs) are known as extreme horizontal branch stars, which is of great importance in stellar evolution theory. The sdO/Bs are generally thought to have a helium-burning core and a thin hydrogen envelope ( M _env < 0.02 M _⊙ ).
Zhenwei Li, Yangyang Zhang, Hailiang Chen, Hongwei Ge, Dengkai Jiang, Jiangdan Li, Xuefei Chen, Zhanwen Han   +7 more
doaj   +1 more source

Hot Stars in the GALEX Ultraviolet Sky Surveys (GUVcat_AISxSDSS_HS) and the Binary Fraction of Hot Evolved Stars

The Astrophysical Journal Supplement Series
We present a catalog of 71,364 pointlike UV sources with Sloan Digital Sky Survey (SDSS) photometry and GALEX far-UV (FUV)−near-UV (NUV) ≤0.1 mag.
Luciana Bianchi
doaj   +1 more source

Spitzer Studies of Ultracool Subdwarfs: Metal-poor Late-type M, L and T Dwarfs

, 2005
Recent discoveries from red optical proper motion and wide-field near-infrared surveys have uncovered a new population of ultracool subdwarfs, metal-poor stars and brown dwarfs extending into the late-type M, L and possibly T spectral classes. These objects are among the first low-mass stars and brown dwarfs formed in the Galaxy, and are valuable ...
openaire   +2 more sources