Any colour you like: The diverse chromaticities of white dwarfs
Abstract
Main sequence stars have perceived colours ranging from orange to white to blue with increasing effective temperature. This is because their atmospheric opacities cause only minor deviations from blackbody colours when integrated over the broadband sensitivity curves of the human visual system. White dwarfs can have much denser atmospheres, reaching ~ 1 g/cm3 for the coolest known objects. If metals such as carbon, calcium, or sodium are present in these ultra-dense atmospheres, extreme broadening of atomic and molecular opacities can produce optical spectra that diverge significantly from blackbodies. We investigated how the combination of temperature and chemical composition can affect the perceived colours (chromaticity) of white dwarfs. While we found that most white dwarfs are similar in colour to blackbodies, we also demonstrate examples of known stars that would appear yellow, green, cyan, pink, or purple if viewed close enough for their stellar discs to be resolved. We examined the chromaticity distribution for the volume-limited 20 pc local sample of white dwarfs finding a median correlated colour temperature of ~= 6800 K, establishing that, on average, white dwarfs are indeed white in colour. Finally we show how white dwarf spectral models can be used to generate colour-accurate images of their stellar discs as they would appear from up close.
Related
- Temperature effects on white dwarfs in modified gravity
- Magnetically Confined Mountains on Accreting White Dwarfs
- Tidal Properties of White Dwarfs Admixed with Fermionic Dark Matter
- Slowly rotating white dwarfs in f (R, T ) = R + 2λT gravity: structure and stationary tidal response
- Exploring the origin of slow-rotating pulsars: Emission from STARS simulated white dwarfs
BibTeX
@misc{hollands2026colour,
title = {{Any colour you like: The diverse chromaticities of white dwarfs}},
author = {Mark A. Hollands and Boris T. Gaensicke and Pier-Emmanuel Tremblay and Detlev Koester},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.18966},
eprint = {2610.18966},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.18966},
}
RIS
TY - UNPB
TI - Any colour you like: The diverse chromaticities of white dwarfs
AU - Mark A. Hollands
AU - Boris T. Gaensicke
AU - Pier-Emmanuel Tremblay
AU - Detlev Koester
PY - 2026
DA - 2026/10/13
PB - arXiv
DO - 10.48550/arxiv.2610.18966
UR - https://arxiv.org/abs/2610.18966
AB - Main sequence stars have perceived colours ranging from orange to white to blue with increasing effective temperature. This is because their atmospheric opacities cause only minor deviations from blackbody colours when integrated over the broadband sensitivity curves of the human visual system. White dwarfs can have much denser atmospheres, reaching ~ 1 g/cm3 for the coolest known objects. If metals such as carbon, calcium, or sodium are present in these ultra-dense atmospheres, extreme broadening of atomic and molecular opacities can produce optical spectra that diverge significantly from blackbodies. We investigated how the combination of temperature and chemical composition can affect the perceived colours (chromaticity) of white dwarfs. While we found that most white dwarfs are similar in colour to blackbodies, we also demonstrate examples of known stars that would appear yellow, green, cyan, pink, or purple if viewed close enough for their stellar discs to be resolved. We examined the chromaticity distribution for the volume-limited 20 pc local sample of white dwarfs finding a median correlated colour temperature of ~= 6800 K, establishing that, on average, white dwarfs are indeed white in colour. Finally we show how white dwarf spectral models can be used to generate colour-accurate images of their stellar discs as they would appear from up close.
ER -