We report the discovery of three cool brown dwarfs that fall in the effective temperature gap between the latest L dwarfs currently known, with no methane absorption bands in the 1-2.5 µm range, and the previously known methane (T) dwarfs, whose spectra are dominated by methane and water. The newly discovered objects were detected as very red objects in the Sloan Digital Sky Survey imaging data and have JHK colors between the red L dwarfs and the blue Gl 229B-like T dwarfs. They show both CO and CH(4) absorption in their near-infrared spectra in addition to H(2)O, with weaker CH(4) absorption features in the H and K bands than those in all other methane dwarfs reported to date. Due to the presence of CH(4) in these bands, we propose that these objects are early T dwarfs. The three form part of the brown dwarf spectral sequence and fill in the large gap in the overall spectral sequence from the hottest main-sequence stars to the coolest methane dwarfs currently known.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1086/312728 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Genetic Mapping by 55K Single-Nucleotide Polymorphism Array Reveals Candidate Genes for Tillering Trait in Wheat Mutant .
Genes (Basel)
December 2024
Henan Technology Innovation Centre of Wheat/National Engineering Research Centre for Wheat, Henan Agricultural University, Zhengzhou 450046, China.
Background: The tiller number is a key agronomic trait for increasing the yield potential of wheat ( L.). A number of quantitative trait loci (QTLs) and key genes controlling tillering have been identified, but the regulatory mechanisms remain unclear.
View Article and Find Full Text PDFTavWA1 is critical for wheat growth by modulating cell morphology and arrangement.
J Integr Plant Biol
January 2025
Key Laboratory of Seed Innovation, Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, 100101, China.
Plant growth is determined by the production of cells and initiation of new organs. Exploring genes that control cell number and cell size is of great significance for understanding plant growth regulation. In this study, we characterized two wheat mutants, ah and dl, with abnormal growth.
View Article and Find Full Text PDFMethane emission from a cool brown dwarf.
Nature
April 2024
Department of Astrophysics, American Museum of Natural History, New York, NY, USA.
Beyond our Solar System, aurorae have been inferred from radio observations of isolated brown dwarfs. Within our Solar System, giant planets have auroral emission with signatures across the electromagnetic spectrum including infrared emission of H and methane. Isolated brown dwarfs with auroral signatures in the radio have been searched for corresponding infrared features, but only null detections have been reported.
View Article and Find Full Text PDFMethane throughout the atmosphere of the warm exoplanet WASP-80b.
Nature
November 2023
Space Telescope Science Institute, Baltimore, MD, USA.
The abundances of main carbon- and oxygen-bearing gases in the atmospheres of giant exoplanets provide insights into atmospheric chemistry and planet formation processes. Thermochemistry suggests that methane (CH) should be the dominant carbon-bearing species below about 1,000 K over a range of plausible atmospheric compositions; this is the case for the solar system planets and has been confirmed in the atmospheres of brown dwarfs and self-luminous, directly imaged exoplanets. However, CH has not yet been definitively detected with space-based spectroscopy in the atmosphere of a transiting exoplanet, but a few detections have been made with ground-based, high-resolution transit spectroscopy including a tentative detection for WASP-80b (ref.
View Article and Find Full Text PDFEfficient capture and highly sensitive analysis of okadaic acid by three-dimensional covalent organic frameworks with hydroxyl surface engineering.
J Chromatogr A
October 2023
College of Chemistry, Fuzhou University, Fuzhou 350108, People's Republic of China; Engineering Technology Research Center on Reagent and Instrument for Rapid Detection of Product Quality and Food Safety in Fujian Province, Fuzhou University, Fuzhou 350108, People's Republic of China. Electronic address:
A novel three-dimensional covalent organic framework (3D-COF) with content-tunable and active hydroxyl groups (OH) on the pore walls was developed and adopted for the high-performance capture of okadaic acid (OA) marine toxins. Using pore-surface engineering, the integration of linear building blocks (4,4'-diamino-3,3'-biphenyldiol, BD(OH) and benzidine, BD) with the 3D structural building block backbone (4,4',4'',4'''-methane-tetrayltetrabenzaldehyde, TFPM) was achieved. By adjusting the ratio of BD(OH), functional multicomponent-COFs [OH]-BD-TFPM COFs (X = 25%) were synthesized, which offered ideal access to convert a conventional COF into a functional platform with multiple-mode interactions of hydrophobic and hydrophilic groups for OA capture.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!