BROWN DWARFS: GEOGRAPHY
NEWS: Webb Telescope has provided
detailed weather maps of brown dwarfs, revealing blazingly hot temperatures and
toxic atmospheric conditions.
WHAT’S IN THE NEWS?
Brown Dwarfs
- Definition: Astronomical objects with masses between the
heaviest gas giant planets and the lightest stars; unable to sustain
hydrogen fusion.
- Mass Range:Typically between 13 and 80 Jupiter masses.
- Spectral Types: Classified as L, T, and Y
dwarfs based on temperature and spectral characteristics.
Characteristics
- Formation: Form from the collapse of a gas cloud, similar
to stars.
- Fusion: Can burn deuterium if above ~13 Jupiter
masses, but briefly.
Temperature:
- L dwarfs: 1,300 to 2,000 K
- T dwarfs: 700 to 1,300 K
- Y dwarfs: Below 700 K
Detection Method:
·
Primarily
detected through infrared observations due to low temperatures and faint
optical visibility.
Key Instruments:
·
Wide-field
Infrared Survey Explorer (WISE)
·
Vera C.
Rubin Observatory
Role in Galactic Evolution
- Galactic Tracers: Provide insights into the
formation and evolution of the Milky Way.
- Longevity: Their stability and abundance make them
useful for studying the galaxy's early history.
Evolution
- Binary Systems: Some brown dwarfs begin as
binary systems but often drift apart due to weak gravitational binding and
interactions with other stellar objects.
- Lifecycle: Form from molecular cloud collapse, then cool
and contract over time.
James Webb Space Telescope (JWST)
Mission
- Purpose: Successor to the Hubble Space Telescope;
designed to study star and planet formation, galaxy evolution, and search
for habitable exoplanets.
- Contributors: NASA, ESA, CSA.
Technical Specifications
- Instruments: Near Infrared Camera (NIRCam), Mid-Infrared
Instrument (MIRI), Near Infrared Spectrograph (NIRSpec), Fine Guidance
Sensor/Near InfraRed Imager and Slitless Spectrograph (FGS/NIRISS).
- Location: Operates at the second Lagrange point (L2),
1.5 million kilometers from Earth, minimizing infrared interference from
Earth.
Achievements and Discoveries
- Early Universe: Provides views of the early
universe, observing light from the first galaxies after the Big Bang.
- Exoplanet Atmospheres: Studies exoplanet
atmospheres, detecting water vapor, methane, and other biomarkers.
- Stellar Nurseries: Investigates star formation
regions, revealing processes leading to the birth of stars and planetary
systems.
Source: https://www.thehindu.com/sci-tech/science/webb-telescope-reveals-wild-weather-on-cosmic-brown-dwarfs/article68413285.ece