Nav: Home

New way to weigh a white dwarf: Use Hubble Space Telescope

June 09, 2017

Astronomers have used, for the first time, a novel method to determine the mass of a nearby dead star. The star is a "white dwarf," the shrunken corpse of a star like our sun after it has burned up its nuclear fuel. The new method is based on the bending of a beam of light near a massive object -- the same phenomenon that was seen during the total eclipse of the Sun that was used to test Einstein's general theory of relativity a century ago. Now, astronomers have achieved a solid estimate of the mass of a white dwarf by measuring the deflection of light rays as they pass near the star.

Using the sharp vision of NASA's Hubble Space Telescope, the research team was able to see how much the white dwarf is bending the light from a background star -- a measurement astronomers need in order to gauge the white dwarf's mass. The team's result will appear in the journal Science on June 9, 2017.

"This measurement is a triumph for the Hubble Space Telescope, a wonderful confirmation of theoretical predictions, and a beautiful reprise of the Einstein solar eclipse observations of a century ago," said team member Howard Bond, Professor of Practice in the Department of Astronomy and Astrophysics at Penn State, and Astronomer Emeritus at NASA's Space Telescope Science Institute, the science operations center for the Hubble Space Telescope.

This observation is the first time Hubble has witnessed this type of effect created by a star. The data provide a solid estimate of the white dwarf's mass and yield insights into theories of its structure and composition. Hubble observed the white dwarf, Stein 2051B, as it passed in front of a background star. During the close alignment, the white dwarf's gravity bent the light from the more distant star, making it appear offset by about 2 milliarcseconds from its actual position.

Bond compared the mass that the Hubble team determined for the white dwarf -- 68 percent of the mass of our sun -- with the theoretical predictions of its mass, based on the known radius of the star and the properties of the extremely dense matter that makes up a white dwarf. "The agreement of the theoretical prediction with the measurement we were able to make with Hubble was astonishingly good," Bond said.

The researchers plan to use Hubble to conduct a similar microlensing study with Proxima Centauri, our solar system's closest stellar neighbor.

The Hubble analysis also helped the astronomers to verify independently the theory of how a white dwarf's radius is determined by its mass, an idea first proposed in 1935 by astronomer Subrahmanyan Chandrasekhar. "Our measurement is a nice confirmation of white-dwarf theory, and it even tells us the internal composition of a white dwarf -- that it is made of carbon and oxygen," Bond said.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.
-end-
CONTACTS

Howard Bond: heb@psu.edu, (+1) 410-530-1007

Barbara Kennedy (Penn State PIO): BarbaraKennedy@psu.edu, (+1) 814-863-4682

Donna Weaver and Ray Villard (STScI PIOs): dweaver@stsci.edu / villard@stsci.edu, (+1) 410-338-4493 and (+1) 410-338-4514

Penn State

Related Hubble Space Telescope Articles:

New way to weigh a white dwarf: Use Hubble Space Telescope
For the first time, astronomers have used a novel method to determine the mass of a type of star known as a 'white dwarf' -- the shrunken corpse of a dead star that used to be like our sun.
NASA's James Webb space telescope completes acoustic and vibration tests
At NASA's Goddard Space Flight Center in Greenbelt, Maryland the James Webb Space Telescope team completed the acoustic and vibration portions of environmental testing on the telescope.
Probing seven worlds with NASA's James Webb Space Telescope
With the discovery of seven earth-sized planets around the TRAPPIST-1 star 40 light years away, astronomers are looking to the upcoming James Webb Space Telescope to help us find out if any of these planets could possibly support life.
NASA restarts rigorous vibration testing on the James Webb Space Telescope
Testing on the James Webb Space Telescope successfully resumed last week at NASA's Goddard Space Flight Center, in Greenbelt, Md.
Robot would assemble modular telescope -- in space
A new concept in space telescope design uses a modular structure and an assembly robot to build an extremely large telescope in space, performing tasks in which astronaut fatigue would be a problem.
Science instruments of NASA's James Webb Space Telescope successfully installed
With surgical precision, two dozen engineers and technicians successfully installed the package of science instruments of the James Webb Space Telescope into the telescope structure.
James Webb Space Telescope's golden mirror unveiled
NASA engineers recently unveiled the giant golden mirror of NASA's James Webb Space Telescope as part of the integration and testing of the infrared telescope.
Earth-space telescope system produces hot surprise
Combining an orbiting radio telescope with telescopes on Earth made a system capable of the highest resolution of any observation ever made in astronomy.
NASA marks major milestones for the James Webb Space Telescope
NASA's James Webb Space Telescope just got a little closer to launch with the completion of cryogenic testing on its science cameras and spectrographs and the installation of the final flight mirrors.
NASA's James Webb Space Telescope secondary mirror installed
The sole secondary mirror that will fly aboard NASA's James Webb Space Telescope was installed onto the telescope at NASA's Goddard Space Flight Center in Greenbelt, Maryland, on March 3, 2016.

Related Hubble Space Telescope Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Setbacks
Failure can feel lonely and final. But can we learn from failure, even reframe it, to feel more like a temporary setback? This hour, TED speakers on changing a crushing defeat into a stepping stone. Guests include entrepreneur Leticia Gasca, psychology professor Alison Ledgerwood, astronomer Phil Plait, former professional athlete Charly Haversat, and UPS training manager Jon Bowers.
Now Playing: Science for the People

#524 The Human Network
What does a network of humans look like and how does it work? How does information spread? How do decisions and opinions spread? What gets distorted as it moves through the network and why? This week we dig into the ins and outs of human networks with Matthew Jackson, Professor of Economics at Stanford University and author of the book "The Human Network: How Your Social Position Determines Your Power, Beliefs, and Behaviours".