The BU White Dwarf Group

Boston Skyline

Welcome to the home page of the BU White Dwarf group, headquartered a few blocks from Fenway Park in Boston, MA, USA.

Our research focuses on white dwarf stars and their connection to the endpoints of stars, binary, and planetary systems. Our work is supported by Boston University, the Institute for Astrophysical Research, the National Aeronautics and Space Administration (NASA), the National Science Foundation (NSF), and the Massachusetts Space Grant Consortium.


Recent news and group updates:
Research updates can be found below and on the news page.

Written in the Stars

By JJ HermesDecember 20th, 2024

A story we ❤️about how exploring the Universe can re-ignite passion. And we don't mind that it's about looking at our white dwarf spectra in @jjhermes.bsky.social group 🤩🔭
www.bu.edu/articles/202...

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— Sloan Digital Sky Surveys (@sdssurveys.bsky.social) December 12, 2024 at 3:58 PM

BU White Dwarf researcher Ariyana Bonab was featured in a November 2024 video profile by The Brink magazine for her research in Summer 2024 visually classifying more than 50,000 spectra of white dwarf stars from SDSS-V. The five-minute video is well worth a watch!

Signposts of Remnant Planetary Systems

By JJ HermesAugust 12th, 2024
The infrared light curve of a known highly variable white dwarf, WD 0145+234 (Swan et al. 2021), showing the major brightening in 2018, likely from collisions in the debris disk. We sought to discover more similar remnant planetary systems (adapted from Guidry et al. 2024).

In June 2024, a manuscript led by graduate student and BUWD member Joseph Guidry (Guidry, Hermes, De et al. 2024) took a look at infrared variability of white dwarfs as seen over many years from NASA's Wide-field Infrared Survey Explorer (WISE) space telescope, discovering dozens of new infrared-variable white dwarfs that are likely to be host to remnant planetary systems. Some white dwarfs with planetary systems host dusty debris that causes an infrared excess, and collisions within the debris disks often cause infrared variability. The manuscript has been accepted in The Astrophysical Journal.

Dr. Tyler Heintz

By JJ HermesAugust 12th, 2024
BUWD group member Dr. Tyler Heintz with PI Hermes.

Massive congratulations to Dr. Tyler Heintz, who successfully defended his PhD dissertation on Tuesday July 23, 2024! Tyler has been at BU throughout the entire history of the BUWD research group, and has become expert in the reliability of white dwarf cosmochronology (age-dating white dwarf stars).

EuroWD Conference, July 2024

By JJ HermesAugust 12th, 2024
BUWD group members in Barcelona.

Three members of the BU White Dwarf group attended the 23rd European Workshop on White Dwarfs, held in July 2024 in Barcelona. We will be hosting the 24th meeting in Summer 2026 in Boston!

Testing Ages Using Spectroscopy of White Dwarfs

By JJ HermesMay 27th, 2024
An example of one widely separated pair of white dwarf stars (both marked with a yellow box), each analyzed independently to determine their ages. In this case, the two stars move together on the sky and are both at the same distance (59.5 pc); they are separated from each other by roughly 1500 au (credit Aladin / PanSTARRS survey).

In May 2024, a manuscript led by graduate student and BUWD member Tyler Heintz (Heintz, Hermes, Tremblay et al. 2024) announced the most detailed test of white dwarf ages measured from spectroscopic fits in wide WD+WD binaries. By comparing the age estimates of wide pairs of stars that should have both been born at the same time, using fits using both photometry and spectroscopy, Tyler provided one of the most reliable tests of current age-dating methods of white dwarf stars. This work shows that photometry + parallax (distance) measurements returns more reliable results for fainter white dwarfs. It also finds further evidence of a significant merger fraction among wide WD+WD binaries, where roughly 20% are inconsistent with a monotonically increasing initial-final mass relation. The manuscript has been published in The Astrophysical Journal.