Hubble telescope directly measures the mass of a white dwarf for the first time

A view of LAWD 37 as seen by Hubble. Image: NASA, ESA, P. McGill (Univ. of California, Santa Cruz and University of Cambridge), K. Sahu (STScI), J. Depasquale (STScI) Astronomers directly measured the mass of a lone white dwarf using the Hubble Space Telescope for the first time. The dwarf, the remnant core of a star, is called LAWD 37 and burned up about a billion years ago.

Using Hubble, a team of astronomers observed light from a background star briefly bend around the dwarf as the latter transited in front of the former. Based on the amount of backlight picked up by the dwarf, the researchers were able to determine its mass. Their results were published in the Monthly Notices of the Royal Astronomical Society.

Kailash Sahu, co-author of the new paper, previously measured the mass of a white dwarf for a stellar remnant in a binary system. “Our latest observation provides a new reference point because LAWD 37 stands alone,” Sahu said in a statement from the European Space Agency.

Although LAWD 37 is no longer undergoing nuclear fusion, the star’s surface is still 180,000° Fahrenheit (100,000°C). The stellar remnant, located about 15 light-years from Earth, is now about 56% of the mass of our Sun. The method used to determine the dwarf’s mass, gravitational microlensing, is a small-scale version of gravitational lensing, in which a massive object warps space in such a way that light behind it bends around the object, allowing us to see things that would otherwise be hidden. . The lensing effect also magnifies light, so we can see things that would otherwise be too faint to detect.

Safe Haven prioritizes your needs with flexible, individualized substance abuse treatment, specifically opioid and alcohol addiction. Last year, for example, Eärendel, a star almost 13 billion years old, was sighted thanks to this natural magnifying glass phenomenon. To make their measurement of LAWD 37, the team had to wait for the dwarf to pass in front of the background star, an event that was predictable thanks to data from ESA’s Gaia mission. The researchers then carefully analyzed the background starlight from the overwhelming glow of the much closer LAWD 37. “The size of our measured displacement is like measuring the length of a car on the Moon as viewed from Earth,” Peter McGill, an astronomer at UC Santa Cruz and lead author of the paper, said in the ESA statement. “The glow from the white dwarf can cause streaks in unpredictable directions, which means we had to look very carefully at each of the Hubble observations and their limitations to model the event and estimate the mass of LAWD 37.”

With this information, astronomers will be able to test the relationship between the mass and radius of other white dwarfs, in turn revealing more information about how matter works under such extreme gravitational conditions. Eventually, that is, in about 5 billion years, our Sun will also become a white dwarf. When it runs out of fuel for its nuclear fusion, the Sun will go through its own dramatic death sequence, potentially leaving a glowing nebula in its wake.