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.

Probing Exoplanets Around Massive Stars

By JJ HermesDecember 20th, 2024
Fraction of white dwarfs showing photospheric metals in our Hubble Space Telescope ultraviolet sample (orange) as a function of white dwarf mass (top x-axis label) and main-sequence progenitor mass (bottom x-axis label). The most massive white dwarfs exhibit significantly less metal pollution (from Ould Rouis et al. 2024).

In November 2024, a manuscript led by graduate student and BUWD member Lou Baya Ould Rouis (Ould Rouis, Hermes, Gaensicke et al. 2024) was accepting which showed that the most massive white dwarfs (>0.8 solar masses) show metal pollution significantly less frequently than more normal-mass white dwarfs. Specifically, just 11% of white dwarfs that begin their lives as stars >3.5 solar masses on the main sequence show metals from remnant planetary systems, while 44% of white dwarfs that begin their lives as stars <2 solar masses show metals. We have also shown that mergers are unlikely to be the main explanation for this discrepancy. The findings likely have implications for planet formation and/or survival around massive stars on the main sequence which are hard to search for exoplanets using traditional techniques. The manuscript has been accepted in The Astrophysical Journal.

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...

[image or embed]

— 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!