Four new DAQ white dwarfs discovered

Astronomers from the College of Oklahoma and their colleagues report the detection of 4 white dwarf stars of a just lately found uncommon DAQ spectral subclass. The newfound white dwarfs are barely extra huge than the sun. The discovering was detailed in a research paper printed March 13 on the preprint server arXiv.

The primary DAQ white dwarf was found in 2020, and obtained the designation J055134.612+413531.09, or J0551+4135 for brief. The researchers that detected J0551+4135 discovered that its spectrum is qualitatively just like a typical hydrogen-atmosphere white dwarf, however with the addition of quite a few absorption strains from atomic carbon. Thus, they categorised this object as a primary instance of a brand new DAQ spectral subclass, which might be distinguished by a singular hydrogen/carbon combined ambiance.

On this newest research, the group of astronomers led by College of Oklahoma’s Mukremin Kilic has carried out a research of the bodily properties of close by huge white dwarfs. By performing spectroscopic observations of some candidate white dwarfs, they discovered that 4 of them are of DAQ subclass.

“By way of follow-up spectroscopy of huge white dwarf candidates inside 100 percent, we recognized two new DAQ white dwarfs with combined carbon and hydrogen atmospheres. As well as, based mostly on an in depth mannequin ambiance evaluation, we demonstrated that two extra DAQ white dwarfs had been missed within the literature,” the researchers wrote within the paper.

The brand new DAQ white dwarfs are designated J0205+2057, J0831−2231, J0958+5853 and J2340−1819. They’ve lots inside the vary of 1.13–1.19 solar masses, whereas their efficient temperatures had been discovered to be between 13,836 and 16,871 Ok. The cooling age of those white dwarfs was estimated to oscillate round 1 billion years.

Subsequently, the checklist of identified DAQ white dwarfs now incorporates 5 objects. 4 of them are positioned close by, inside solely 330 light years away from the Earth.

In line with the research, the galactic space velocities of the 4 white dwarfs recommend the Milky Way’s thick disk or halo origin. Furthermore, fast rotation was detected in a minimum of two of those objects. These properties make them just like heat white dwarfs of spectral sort DQ—these with carbon absorption options of their spectra.

Primarily based on the collected knowledge and the similarities between DAQ and heat DQ white dwarfs, the astronomers assume that the DAQ inhabitants are white dwarf merger remnants. Specifically, these objects probably emerge as huge DA white dwarfs, produced in white dwarf mergers.

“Additional theoretical research of the spectral evolution of merger merchandise, together with scorching and heat DQs and the DAQs could be helpful for understanding the emergence of the DAQ subclass,” the researchers concluded.

© 2024 Science X Community