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 from Brightsurf:

Spitzer space telescope legacy chronicled in Nature Astronomy
A national team of scientists Thursday published in the journal Nature Astronomy two papers that provide an inventory of the major discoveries made possible thanks to Spitzer and offer guidance on where the next generation of explorers should point the James Webb Space Telescope (JWST) when it launches in October 2021.

Unveiling rogue planets with NASA's Roman Space Telescope
New simulations show that NASA's Nancy Grace Roman Space Telescope will be able to reveal myriad rogue planets - freely floating bodies that drift through our galaxy untethered to a star.

Hubble makes the first observation of a total lunar eclipse by a space telescope
Taking advantage of a total lunar eclipse, astronomers using the NASA/ESA Hubble Space Telescope have detected ozone in Earth's atmosphere.

Stunning space butterfly captured by ESO telescope
Resembling a butterfly with its symmetrical structure, beautiful colours, and intricate patterns, this striking bubble of gas -- known as NGC 2899 -- appears to float and flutter across the sky in this new picture from ESO's Very Large Telescope (VLT).

Hubble marks 30 years in space with tapestry of blazing starbirth
NASA is celebrating the Hubble Space Telescope's 30 years of unlocking the beauty and mystery of space by unveiling a stunning new portrait of a firestorm of starbirth in a neighboring galaxy.

CHEOPS space telescope ready for scientific operation
CHEOPS has reached its next milestone: Following extensive tests in Earth's orbit, some of which the mission team was forced to carry out from home due to the coronavirus crisis, the space telescope has been declared ready for science.

Scientists build a 'Hubble Space Telescope' to study multiple genome sequences
Scientists can now simultaneously compare 1.4 million genetic sequences, helping classify how species are related to each other at far larger scales than previously possible.

Kepler Space Telescope's first exoplanet candidate confirmed
An international team of astronomers announced the confirmation of the first exoplanet candidate identified by NASA's Kepler Mission.

Space telescope detects water in a number of asteroids
Using the infrared satellite AKARI, a Japanese research team has detected the existence of water in the form of hydrated minerals in a number of asteroids for the first time.

The Hubble Space Telescope discovers the most distant star ever observed
An international team, including researchers from the Instituto de Astrofísica de Canarias (IAC) and the University of La Laguna (ULL), participated in the discovery of a star at a distance of nine billion lightyears from Earth.

Read More: Hubble Space Telescope News and Hubble Space Telescope Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.