Scientists have undertaken a study on the first white dwarf to exhibit periodic transits of planetary debris.
What is the white dwarf?
The mysterious white dwarf is known as WD 1145+017 and it showcases periodic transits of planetary debris. Researchers have carried out the study to determine the parameters of the white dwarf and find insights into the qualities of the debris which surround it periodically.
The white dwarf is located around 570 light years away, with a size of about 2% of the sun and an approximate mass of 0.63 solar masses. It is the first known white dwarf with a transit of planetary debris orbiting it, and these transits of debris were first noticed by astronomers in 2015. Other observations have suggested that the object which orbits the white dwarf, which happens every 4.5 hours, is an asteroid being shredded apart by the white dwarf, however, more research is needed to add to this possible explanation.
What were the results of the study?
The researchers wrote that they have achieved: “The first simultaneous fast optical spectrophotometry and broad-band photometry of the system, obtained with the Gran Telescopio Canarias (GTC0).” They made multiple observations about the white dwarf and the debris surrounding it as part of the study.
The researchers have been able to confirm:
- No significant colour differences by dividing the GTC spectrophotometry into five wavelength bands, thereby confirming grey transits in the optical
- The achromatic nature of the transits that can allow the presence of small-sized particles is arguably caused by the absorption by an optically thick structure
- The longest and deepest transit recorded in the data exhibits a complex structure around minimum light that can be well modelled by multiple overlapping dust clouds
- The parameters of the white dwarf have been determined using archival photometry and using the Gaia Data Release 2
- Time-resolved spectroscopy with a higher signal-to-noise ratio may allow more information on the white dwarf and the debris
The study was essential in the effort to investigate the qualities of the white dwarf and the debris surrounding it, but there may remain further research to be done to reveal more details about the star and its debris.