NASA’s Hubble Space Telescope has captured unprecedented views of dramatic weather changes on WASP-121b, a “hot Jupiter” exoplanet orbiting dangerously close to its host star 880 light-years away, according to new research published this week.
Overview of WASP-121b
WASP-121b is an exoplanet over 900 light years away that orbits extremely close to its host star, completing one orbit every 1.3 days. This results in the planet having a surface temperature over 2500°C, making the exoplanet’s atmosphere incredibly turbulent.
Key facts about WASP-121b:
- Orbits a hot A-type star around 2 times more massive and over 3 times hotter than our Sun
- Discovered in 2015 by ground-based telescopes
- One of the hottest known exoplanets with temps over 2500°C
- Orbits very close to its star, with an orbital period of just 1.3 days
- Has a mass and radius 1.2 and 1.9 times greater than Jupiter
- Nicknamed a “hot Jupiter” type exoplanet
New Hubble Observations
Using the powerful Hubble Space Telescope, astronomers have now captured the first time-resolved observations of meteorological variations in the atmosphere of WASP-121b.
Over two nights in 2018, Hubble detected significant variations in the exoplanet’s atmospheric temperatures and winds:
- Temperatures change by over 500°C between the planet’s day side and night side
- Winds detected exceeding 5400 mph – among the fastest winds detected on any exoplanet
- Vast storms observed with cloud formations shifting in just under 12 hours
As lead researcher Dr Emily Deibert explains:
“We picked this planet because we thought its proximity to its star would give us a chance of observing rapid weather changes. And we were right. We saw changes in weather patterns on timescales of only a few hours. We realized we were probably looking at weather, rather than climate.”
These new observations provide an unprecedented glimpse into the turbulent nature and fast rate of change in the atmosphere of this scorching hot Jupiter.
Why Study Exoplanet Weather?
While we cannot yet directly photograph surface features of exoplanets, analyzing subtle changes in their atmospheres as they orbit their stars allows unique insights into their meteorology.
As co-researcher Dr David Sing explains:
“It’s remarkable that we can see so many weather patterns on a planet so far away. But we can learn about some hidden secrets like wind speed and directions high up in the planet’s atmosphere.”
Studying exoplanet weather also helps astronomers better understand the nature, behavior and evolution of planets outside our Solar System. Extreme exoplanets like WASP-121b stretch current atmospheric models to their limits, providing opportunities to refine and improve our understanding of planetary science.
Turbulent ‘Vampire Planet’
Due to its close proximity, WASP-121b is bombarded by tremendous amounts of extreme ultraviolet radiation from its host star as it orbits every 1.3 days. This is steadily eroding the exoplanet’s atmosphere.
“The planet is being evaporated by its host star to the point that heavy metals are escaping the upper atmosphere, said researcher Dr David Sing. “It is bleeding its atmosphere into space.”
This earned WASP-121b the nickname ‘vampire planet’ – as it slowly has its lifeblood drained from this radiation. Understanding the ferocious weather on exoplanets like WASP-121b also helps astronomers better predict their atmospheric evaporation and ultimate fate.
What’s Next
The NASA Hubble team plans to conduct further spectroscopic observations of WASP-121b later this year to capture additional snapshots of weather variations to better understand the nature and cause of these dramatic changes.
As researcher Dr Mikal Evans explains:
“With Hubble we have the first time-resolved observations suggesting meteorological events on an exoplanet, opening up an exciting new frontier in exoplanet atmospheric dynamics studies. We look forward to refining our analysis techniques to collect more definitive exoplanet weather data moving forward.”
These early insights into hot Jupiter weather patterns also set the stage for the upcoming launch of NASA’s James Webb Space Telescope. Scheduled to launch in April 2024, Webb’s advanced infrared instruments will be capable of even more detailed spectroscopic mapping of exoplanet atmospheres in the years ahead.
Key Implications
The key revelations from Hubble’s WASP-121b observations include:
- Proof that we can detect and track weather variability on exoplanets
- Extreme temperature shifts indicating highly dynamic atmospheres
- Evidence of fierce jets streams and vortexes similar to storms on Earth
- Raises prospects of improving global circulation models of hot Jupiters
As we continue to analyze the weather systems on distant exoplanets like WASP-121b, astronomers edge closer to identifying potentially habitable Earth-like worlds elsewhere in the galaxy.
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