brown dwarf Archives

February 24, 2024February 24, 2024 by Laurence Tognetti

Brrr. JWST Looks at the Coldest Brown Dwarf

Artist's illustration of a cold brown dwarf star. (Credit: NASA)

What are the atmospheric compositions of cold brown dwarf stars? This is what a recent study published in The Astronomical Journal hopes to address as an international team of researchers used NASA’s James Webb Space Telescope (JWST) to investigate the coldest known brown dwarf star, WISE J085510.83?071442.5 (WISE 0855). This study holds the potential to help astronomers better understand the compositions of brown dwarf stars, which are also known as “failed stars” since while they form like other stars, they fail to reach the necessary mass to produce nuclear fusion. So, what was the motivation behind using JWST to examine the coldest known brown dwarf star?

January 10, 2024January 10, 2024 by Nancy Atkinson

A Solo Brown Dwarf Found With Auroras

This artist concept portrays the brown dwarf W1935, which is located 47 light-years from Earth. Astronomers using NASA’s James Webb Space Telescope found infrared emission from methane coming from W1935, generating an aurora, a very unexpected discovery. Credit: NASA, ESA, CSA, Leah Hustak (STScI)

Astronomers have used JWST to find a brown dwarf with polar auroras like the Earth, or Jupiter. This is surprising because the brown dwarf, dubbed W1935, is a free-floating object, meaning it isn’t part of another star system. Therefore, there’s no solar wind available to generate any Northern Lights. Instead, the auroras are seemingly generated from methane emissions in the planet’s atmosphere, interacting with the interstellar plasma. Another theory is that it perhaps has an active but unseen moon contributing to the emissions.

September 11, 2023September 22, 2023 by Evan Gough

JWST Accidentally Found 21 Brown Dwarfs

This artist's conception illustrates the brown dwarf named 2MASSJ22282889-431026, observed by NASA's Hubble and Spitzer space telescopes. Brown dwarfs are more massive and hotter than planets but lack the mass required to become stars. Image credit: NASA

When you launch humanity’s most powerful telescope, you expect results. The JWST has delivered excellent results by detecting ancient galaxies, identifying chemicals in exoplanet atmospheres, and peering into star-forming regions with more detail and clarity than any other telescope.

But every time a new telescope is about to enter service, astronomers tell us they’re excited not only about the expected results but also about the surprising results. And like other telescopes, the JWST has also delivered some surprises. While going about its business, the JWST has discovered 21 brown dwarfs.

August 6, 2023August 6, 2023 by Scott Alan Johnston

Two Stars Orbiting Each Other So Closely They Could Fit Inside the Sun

A brown dwarf: an object that weighs in somewhere between Jupiter and the least-massive known star. Credit: NASA/JPL-Caltech.

Astronomers have discovered a pair of star-like objects orbiting each other extremely quickly, with an entire ‘year’ lasting just 1.9 Earth hours. Catchily named ZTF J2020+5033, the system consists of one object which is definitely a small star, and another that straddles the boundary between star and planet. The two objects appear to be very old, and understanding how they came to be orbiting so close together is teaching astronomers more about how solar systems change and evolve.

February 21, 2022February 21, 2022 by Andy Tomaswick

Twin Brown Dwarfs Discovered, Orbiting one Another at Three Times the Distance From the Sun to Pluto

Gravity is a funny force. The gravity of every given object technically impacts every other given object, though, in practice, large distance and small masses make those forces negligible for such interactions. But in some cases, especially when large groups are floating in empty space, gravity can still hold sway over considerable distances. Such is the case with a new pair of brown dwarfs found by astronomers at the Keck Observatory.

January 29, 2021January 29, 2021 by Andy Tomaswick

We Now Have a 3D Map of The 525 Closest Brown Dwarfs

Zooniverse brings out the best of the internet – it leverages the skills of average people to perform scientific feats that would be impossible otherwise. One of the tasks that a Zooniverse project called Backyard Worlds: Planet 9 has been working on has now resulted in a paper cataloguing 525 brown dwarfs, including 38 never before documented ones.

January 11, 2021January 11, 2021 by Paul M. Sutter

Astronomers see Swirling Weather on the Closest Brown Dwarf

An artist's conception of a brown dwarf. A new study identifies CK Vulpeculae as the remnant of a collison between a brown dwarf and a white dwarf. Image: By NASA/JPL-Caltech (http://planetquest.jpl.nasa.gov/image/114) [Public domain], via Wikimedia Commons — An artist's conception of a brown dwarf. Brown dwarfs are more massive than Jupiter but less massive than the smallest main sequence stars. Image: By NASA/JPL-Caltech (http://planetquest.jpl.nasa.gov/image/114) [Public domain], via Wikimedia Commons

Brown dwarfs are the weird not-planets but not-stars in the universe, and astronomers have wondered for decades if their atmospheres are striped like Jupiter’s, or splotchy like the sun’s. A team of astronomers based at the University of Arizona used NASA’s TESS Observatory to find the answer: if you saw a brown dwarf for yourself, it would look more like a giant planet than a star.

December 30, 2020December 30, 2020 by Andy Tomaswick

Astronomers Capture a Direct Image of a Brown Dwarf

First direct image of a brown dwarf star in a system not unlike our own.

The field of exoplanet photography is just getting underway, with astronomers around the world striving to capture clear images of the more than 4000 exoplanets discovered to date. Some of these exoplanets are more interesting to image and research than others. That is certainly the case for a type of exoplanet called a brown dwarf. And now scientists have captured the first ever image of exactly that type of exoplanet.

August 28, 2020August 27, 2020 by Paul M. Sutter

Astronomers find 100 brown dwarfs in our neighborhood

Brown dwarfs are smallish objects sitting somewhere between stars and planets, making them notoriously hard to find. But a recent citizen science project aimed at finding the elusive Planet 9 has instead revealed a treasure trove of these oddities, right next door.

May 6, 2020May 6, 2020 by Evan Gough

Astronomers Can Actually See the Clouds and Weather on Brown Dwarf 6.5 Light-Years Away

Brown dwarfs are in a tough spot. Not quite a star, not quite a planet, they occupy a place between gas giants and stars. They have more mass than gas giants like Jupiter, but not enough to ignite fusion and become a star.

But astronomers still study them. How could they resist?