Debris Disks around White Dwarfs: The DAZ Connection

By M. Kilic, Ted von Hippel, S. Leggett, D. Winget. 2006

133 citations recorded by the source corpus.

We present near-infrared spectroscopic observations of 20 previously known DAZ white dwarfs obtained at the NASA Infrared Telescope Facility. Two of these white dwarfs (G29-38 and GD 362) are known to display significant K-band excesses due to circumstellar debris disks. Here we report the discovery of excess K-band radiation from another DAZ white dwarf, WD 0408-041 (GD 56). Using spectroscopic observations, we show that the excess radiation cannot be explained by a stellar or substellar companion, and is likely to be caused by a warm debris disk. Our observations strengthen the connection between the debris disk phenomena and the observed metal abundances in cool DAZ white dwarfs. However, we do not find any excess infrared emission from the most metal rich DAZs with Teff = 16,000-20,000 K. This suggests that the metal abundances in warmer DAZ white dwarfs may require another explanation.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/adc9002c3a48eb6d57c8b26b98e80d7d47171ceb

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In Astronomy and Astrophysics

1. J. Farihi
2. D. Koester
3. Michael Jura
4. Amy Bonsor
5. A. Mustill
6. B. Zuckerman
7. M. C. Wyatt
8. M. Strauss

In Instrumentation

1. J. Farihi
2. A. Mustill
3. D. Koester
4. Michael Jura
5. Pierre Bergeron
6. M. C. Wyatt
7. Amy Bonsor
8. M. Strauss

Citations in the corpus

• Externally Polluted White Dwarfs with Dust Disks (2007, methodology): “Kilic et al. (2006b) have shown that GD 56 is unusual in having a particularly marked excess at 2 µm, and as seen in Figure 2, our model Agd56 with an inner disk temperature of 1200 K completely fails.”
• On the Spectral Evolution of Cool, Helium-Atmosphere White Dwarfs: Detailed Spectroscopic and Photometric Analysis of DZ Stars (2007, methodology): “Cool DZ stars in these regions, if they exist, should be found by a more careful search of the SDSS spectroscopic archive, or with the help of reduced proper-motion surveys similar to that undertaken by Kilic et al. (2006b).”
• THE LINK BETWEEN PLANETARY SYSTEMS, DUSTY WHITE DWARFS, AND METAL-POLLUTED WHITE DWARFS (2012, background): “…abundance analysis of narrow metal lines in the photosphere of the target white dwarf, or detection of gaseous emission lines (Zuckerman et al. 2003; Koester et al. 2005; Reach et al. 2005; Kilic et al. 2006; Gänsicke et al. 2006; von Hippel et al. 2007; Farihi et al. 2010; Debes et al. 2011b).”
• Can Planets Survive Stellar Evolution? (2007, background): “On the other hand, three white dwarfs are known to possess an infrared excess, GD 362 (Becklin et al. 2005; Kilic et al. 2005), G29-38 (Zuckerman&Becklin 1987; Jura 2003), and the recently discovered GD 56 (Kilic et al. 2006).”
• INFRARED SIGNATURES OF DISRUPTED MINOR PLANETS AT WHITE DWARFS (2009, background): “…evidence of circumstellar disks; either by infrared excess (Farihi et al. 2008b; Kilic & Redfield 2007; von Hippel et al. 2007; Jura et al. 2007a; Kilic et al. 2006; Becklin et al. 2005; Kilic et al. 2005; Graham et al. 1990; Zuckerman & Becklin 1987b), or by broad, double-peaked optical…”
• ANCIENT PLANETARY SYSTEMS ARE ORBITING A LARGE FRACTION OF WHITE DWARF STARS (2010, background): “…massive rocky objects that first are tidally disrupted into a disk that orbits a white dwarf and subsequently are accreted onto the white dwarf (Jura 2003; Gansicke et al 2006; Kilic et al. 2006; von Hippel et al 2007; Farihi et al. 2009; Jura et al. 2009b; Farihi et al. 2010a; Melis et al 2010).”
• Circumstellar Debris and Pollution at White Dwarf Stars (2016, methodology): “…among these first half dozen examples is that the infrared excesses all become apparent by 2− 3µm, a trait that is now known to be common (but not universal), and hence the most prominent of these are detectable from the ground using K-band spectroscopy (Kilic et al., 2006; Kilic & Redfield, 2007).”
• Models of low-mass helium white dwarfs including gravitational settling, thermal and chemical diffusion, and rotational mixing (2016, background): “…WDs, the presence of metals in their atmosphere is explained by accretion from circumstellar debris discs formed by tidal disruption of planetary bodies (e.g. Debes & Sigurdsson 2002; Jura et al. 2007), which are detectable through excess flux in the IR (e.g. Farihi et al. 2009; Kilic et al. 2006).”
• POLLUTION OF SINGLE WHITE DWARFS BY ACCRETION OF MANY SMALL ASTEROIDS (2008, background): “There are strong arguments that the approximately ten single white dwarfs known to have an infrared excess (Kilic et al. 2006a, 2006b, Kilic & Redfield 2007, Mullally et al. 2007, Jura et al. 2007b, von Hippel et al. 2007, Farihi et al. 2008a, b) are accreting tidallydisrupted asteroids.”
• Dynamical effects of stellar mass-loss on a Kuiper-like belt (2011, background): “The best models to explain these systems (Debes & Sigurdsson 2002; Jura 2003; Gänsicke et al. 2006; Kilic et al. 2006; von Hippel et al. 2007; Farihi, Jura & Zuckerman 2009; Farihi et al. 2010b; Melis et al. 2011) suggest that asteroids or comets from the remnants of main-sequence…”