Level 1 - Absolute Beginner
Scientists used the James Webb Space Telescope to study a very cold object called WISE 0855. It is about 7.4 light years from Earth.
It is a brown dwarf. A brown dwarf is bigger than a planet but too small to be a star. WISE 0855 is the coldest one we know.
Webb saw signs of water clouds in its sky. The clouds seem to get thicker and thinner as the object spins. This is the first time anyone has seen water clouds change like this outside our solar system.
- telescope
- a tool for seeing far away things
- brown dwarf
- an object bigger than a planet but smaller than a star
- cloud
- a mass of water drops in the sky
- light year
- the distance light travels in one year
- solar system
- the sun and the planets around it
- spin
- to turn around and around
- thick
- not thin
- cold
- with a low temperature
Level 2 - Elementary
Astronomers using the James Webb Space Telescope have found the first signs of water clouds that change over time on a world outside our solar system. The object is WISE 0855, the coldest known brown dwarf, about 7.4 light years from Earth.
The team, led by Brittany Miles of the University of Arizona, took a spectrum every 15 minutes for 11 hours with Webb's NIRSpec instrument. The object is about 265 kelvin, which is cold enough for water clouds high in its air but too warm for ammonia to freeze.
The data suggest patchy water clouds that move as the object turns. Carbon monoxide changed the most, by up to 10 percent at some wavelengths, and its changes matched those of phosphine. The study was accepted in The Astrophysical Journal, and the team wants more Webb time to learn the spin and the winds.
- astronomer
- a scientist who studies space
- spectrum
- light spread out to show what something is made of
- instrument
- a tool used for measuring
- kelvin
- a unit used to measure temperature
- patchy
- not even, with gaps
- wavelength
- a measure of light color
- phosphine
- a gas made of phosphorus and hydrogen
- accepted
- approved to be published
Level 3 - Intermediate
Using the James Webb Space Telescope, astronomers have gathered the first time resolved evidence that water clouds on a body beyond our solar system change in thickness over time. The target, WISE 0855, is the coldest known brown dwarf, roughly 7.4 light years from Earth, and sits at about 265 kelvin.
A team led by Brittany Miles of the University of Arizona recorded a spectrum every 15 minutes for 11 hours using Webb's NIRSpec instrument, covering wavelengths between 2.87 and 5.27 microns. At that temperature water can condense high in the atmosphere, while ammonia stays gaseous, and comparisons with atmospheric models point to patchy clouds that shift as the object rotates.
The spectra also revealed chemical swings. Carbon monoxide varied the most, up to 10 percent peak to peak at some wavelengths, and moved in step with phosphine, consistent with heat from the interior driving gases upward by convection. The rotation period and some chemical details remain uncertain, so Miles plans additional Webb observations to map the object's winds in three dimensions. The work was accepted in The Astrophysical Journal.
- time resolved
- measured repeatedly to show change over time
- condense
- to change from gas to liquid
- atmospheric
- related to a planet's or object's air
- rotate
- to turn around an axis
- peak to peak
- from the highest to the lowest value
- convection
- movement of heat by rising and sinking gas
- interior
- the inside part
- baseline
- a reference measurement for comparison
Level 4 - Advanced
Astronomers wielding the James Webb Space Telescope have obtained the first time resolved evidence that water clouds beyond our solar system thicken and thin over time. The subject, WISE 0855, is the coldest known brown dwarf, lying roughly 7.4 light years away with a temperature near 265 kelvin, a regime in which water can condense aloft while ammonia remains gaseous.
Led by Brittany Miles of the University of Arizona, the team collected a spectrum every 15 minutes across 11 hours with the NIRSpec instrument, spanning 2.87 to 5.27 microns. Comparing the data with atmospheric and structural models, they inferred patchy water clouds that evolve as the object rotates, an ambiguous but compelling signature of weather on a frozen world.
Chemistry fluctuated too. Carbon monoxide displayed the strongest swings, as much as 10 percent peak to peak at certain wavelengths, and tracked phosphine, a pattern consistent with internal heat lofting gases upward through convection. Earlier Spitzer monitoring had hinted at variability of 3 to 5 percent, but Webb's sensitivity allows far finer detail. Because the rotation period and some chemical specifics remain uncertain, Miles intends to gather further baseline observations to chart the object's three dimensional atmospheric motion. The study was accepted in The Astrophysical Journal.
- wield
- to use a tool with skill
- regime
- a set of conditions in which something happens
- aloft
- high up in the air
- infer
- to conclude from evidence
- ambiguous
- open to more than one meaning
- fluctuate
- to change up and down
- loft
- to lift high
- sensitivity
- the ability to detect small signals
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