Results of the summarizing process for the arXiv paper: 2303.16330v1

White dwarf stars are known to emit excess infrared flux which is believed to originate from either a dusty debris disk or a cool companion. In this study, the authors present near-infrared spectroscopic observations of seven white dwarfs with previously identified infrared excesses using Keck/MOSFIRE, Gemini/GNIRS and Gemini/Flamingos-2. The team confirmed the presence of dust disks around four white dwarfs (Gaia J0611-6931, Gaia J0006+2858, Gaia J2100+2122 and WD 0145+234) as well as two new white dwarf brown dwarf pairs (Gaia J0052+4505 and Gaia J0603+4518). They also detected near-infrared metal emissions (Mg I, Fe I and Si I) from a gaseous component of the disk in three of the dust disk systems for the first time. To constrain the geometric properties of each dust disk system they developed a new Markov Chain Monte Carlo framework. Interestingly in three systems studied by the team both the dust disk and gas disk appear to coincide spatially. Furthermore broad molecular absorption features typically seen in L dwarfs were identified in two brown dwarf white dwarf pairs. However, the origin of infrared excess around Gaia J0723+6301 remains unknown. This study highlights how near-infrared spectroscopy can be used to determine sources of infrared excess around white dwarfs which has been detected photometrically in hundreds of systems so far. The findings provide valuable insights into understanding these mysterious objects' formation and evolution processes.

• White dwarf stars emit excess infrared flux
• Excess infrared flux can originate from a dusty debris disk or a cool companion
• Near-infrared spectroscopic observations were conducted on seven white dwarfs with previously identified infrared excesses
• Dust disks were confirmed around four white dwarfs and two new white dwarf brown dwarf pairs were discovered
• Near-infrared metal emissions (Mg I, Fe I and Si I) were detected from the gaseous component of the disk in three of the dust disk systems for the first time
• A new Markov Chain Monte Carlo framework was developed to constrain the geometric properties of each dust disk system
• In three systems studied by the team, both the dust disk and gas disk appear to coincide spatially
• Broad molecular absorption features typically seen in L dwarfs were identified in two brown dwarf white dwarf pairs
• The origin of infrared excess around Gaia J0723+6301 remains unknown
• Near-infrared spectroscopy can be used to determine sources of infrared excess around white dwarfs
• Findings provide valuable insights into understanding these mysterious objects' formation and evolution processes.

Exploring the Infrared Excess Around White Dwarf Stars

White dwarf stars are some of the most mysterious objects in our universe. They are incredibly dense, and emit excess infrared flux which has been a source of fascination for astronomers for many years. It is believed that this infrared flux originates from either a dusty debris disk or a cool companion. To better understand these enigmatic objects, researchers have conducted near-infrared spectroscopic observations on seven white dwarfs with previously identified infrared excesses using Keck/MOSFIRE, Gemini/GNIRS and Gemini/Flamingos-2. The team confirmed the presence of dust disks around four white dwarfs (Gaia J0611-6931, Gaia J0006+2858, Gaia J2100+2122 and WD 0145+234) as well as two new white dwarf brown dwarf pairs (Gaia J0052+4505 and Gaia J0603+4518).

Dust Disks

The research team also detected near-infrared metal emissions (Mg I, Fe I and Si I) from a gaseous component of the disk in three of the dust disk systems for the first time. To constrain the geometric properties of each dust disk system they developed a new Markov Chain Monte Carlo framework. Interestingly in three systems studied by the team both the dust disk and gas disk appear to coincide spatially. This suggests that there may be an underlying connection between them which could provide valuable insights into understanding these mysterious objects' formation and evolution processes.

Brown Dwarfs

In addition to detecting dust disks around white dwarfs, broad molecular absorption features typically seen in L dwarfs were identified in two brown dwarf white dwarf pairs - suggesting that these binary systems may have formed through different mechanisms than single star systems.

Unanswered Questions

However, despite their findings there remain unanswered questions about some sources of infrared excess around white dwarfs - such as Gaia J0723+6301 whose origin remains unknown at this time. Nevertheless this study highlights how near-infrared spectroscopy can be used to determine sources of infrared excess around hundreds of other systems so far which has been detected photometrically - providing valuable insights into understanding these mysterious objects' formation and evolution processes.