Astronomers Measure Wind Speed on a Brown Dwarf

Astronomers have used the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) and NASA’s Spitzer Space Telescope to make the first measurement of wind speed on a brown dwarf — an object intermediate in mass between a planet and a star.

Based on facts known about the giant planets Jupiter and Saturn in our own Solar System, a team of scientists led by Katelyn Allers of Bucknell University realized that they possibly could measure a brown dwarf’s wind speed by combining radio observations from the VLA and infrared observations from Spitzer.

“When we realized this, we were surprised that no one else had already done it,” Allers said.

The astronomers studied a brown dwarf called 2MASS J10475385+2124234, an object roughly the same size as Jupiter, but roughly 40 times more massive, about 34 light-years from Earth. Brown dwarfs, sometimes called “failed stars,” are more massive than planets, but not massive enough to cause the thermonuclear reactions at their cores that power stars.

“We noted that the rotation period of Jupiter as determined by radio observations is different from the rotation period determined by observations at visible and infrared wavelengths,” Allers said.

That difference, she explained, is because the radio emission is caused by electrons interacting with the planet’s magnetic field, which is rooted deep in the planet’s interior, while the infrared emission comes from the top of the atmosphere. The atmosphere is rotating more quickly than the interior of the planet, and the corresponding difference in velocities is due to atmospheric winds.

“Because we expect the same mechanisms to be at work in the brown dwarf, we decided to measure its rotation speeds with both radio and infrared telescopes,” said Johanna Vos, of the American Museum of Natural History.

They observed 2MASS J10475385+2124234 with Spitzer in 2017 and 2018, and found that its infrared brightness varied regularly, likely because of the rotation of some long-lived feature in its upper atmosphere. The team did VLA observations in 2018 to measure the rotation period of the object’s interior.

Just as with Jupiter, they found that the brown dwarf’s atmosphere is rotating faster than its interior, with a calculated wind speed of about 1425 miles per hour. This is significantly faster than Jupiter’s wind speed, about 230 mph.

“This agrees with theory and simulations that predict higher wind speeds in brown dwarfs,” Allers said.

The astronomers said their technique can be used to measure winds not only on other brown dwarfs, but also on extrasolar planets.

“Because the magnetic fields of giant exoplanets are weaker than those of brown dwarfs, the radio measurements will need to be done at lower frequencies than those used for 2MASS J10475385+2124234, said Peter Williams of the Center for Astrophysics, Harvard & Smithsonian, and the American Astronomical Society.

“We’re excited that our method can now be used to help us better understand the atmospheric dynamics of brown dwarfs and extrasolar planets,” Allers said.

Allers, Vos, and Williams, along with Beth Biller of the University of Edinburgh, reported their findings in the journal Science.

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

###

Media Contact:

Dave Finley, Public Information Officer
(575) 835-7302
[email protected]

In Other News…

AUI and NRAO Announce 2022 NAC Bridge Scholarship Recipients

This news article was originally published on NRAO.edu on July 5, 2022.AUI and the National Radio Astronomy Observatory (NRAO) have announced the recipients of the 2022 AUI Board of Trustees NAC Bridge Scholarship Award. Now in its second year, the scholarship...

Pride Month Statement

Pride Month is a time for celebration of LGBTQIA+ communities and commemoration of the Stonewall Uprising of 1969 and the ensuing liberation movement it inspired for the ongoing fight for full equality.  At AUI, we celebrate an environment that is safe and welcoming...

2022 AUI Scholarship Recipients

Below are the six recipients of the 2022 AUI Scholarship conducted by International Scholarship and Tuition Services, Inc. These students will each receive an award of $3,500 per year to aid in defraying expenses at the college or university of their choice. ELIJAH...

Astronomers Reveal First Image of the Black Hole at the Heart of Our Galaxy

This news article was originally published on NRAO.edu on May 12, 2022.Credit: EHT CollaborationAt simultaneous press conferences around the world, including at a National Science Foundation-sponsored press conference at the US National Press Club in Washington, D.C.,...

Scientists Find Elusive Gas From Post-starburst Galaxies Hiding in Plain Sight

This news article was originally published on NRAO.edu on Apr. 25, 2022.Scientists discovered that post-starburst galaxies condense their gas rather than expelling it, begging the question: what’s actually keeping them from forming stars? Post-starburst galaxies were...

Applications Accepted for 2022 Astronomy in Chile Educator Ambassadors Program

Applications are now being accepted for the 2022 Astronomy in Chile Educator Ambassadors Program (ACEAP).

Inspiring, Retaining and Promoting Female Talent in STEM Careers

Retaining and promoting female talent in science, technology, engineering, and mathematics (STEM) is a goal that must be embraced by large scientific facilities, civil society, academia and the private sector.

NRAO Researcher Receives Prestigious Engineering Award

Matthew Morgan, a scientist and research engineer at the National Radio Astronomy Observatory’s Central Development Laboratory, has received a prestigious engineering award for work that has beneficial applications far beyond its original purpose in radio astronomy.

Big Astronomy Hosts Live Talk and Q&A with Astronaut Dr. Sian Proctor

On Friday, February 4 at 7:00 pm EST, join astronaut, geoscientist, explorer and space artist Dr. Sian Proctor for a live talk and Q&A hosted by Big Astronomy.

NRAO Director Tony Beasley Honored as Lifetime AAAS Fellow

Tony Beasley, Director of the National Radio Astronomy Observatory and AUI Vice President for Radio Astronomy Operations, was today elected as a fellow of the American Association for the Advancement of Science (AAAS).

You are now leaving AUI

You will be redirected to the related partnering organization's website.

You will be redirected to
in 4 seconds...

Click the link above to continue or CANCEL