WIRED for EC: New White Dwarfs with WISE Infrared Excesses and New Classification Schemes from the Edinburgh–Cape Blue Object Survey

Dennihy, E.; Clemens, J. C.; Debes, John H.; Dunlap, B. H.; Kilkenny, D.; O'Brien, P. C.; Fuchs, J.

doi:10.3847/1538-4357/aa8ef2

Cited by 24 publications

(20 citation statements)

References 86 publications

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“…To construct the spectral energy distributions for our targets and search for this infrared excess, we collected publicly available photometry from the Sloan Digital Sky Survey (SDSS; Ahn et al 2014) (Skrutskie et al 2006), and the AllWISE surveys (Cutri et al 2014). We dereddened the photometry using the technique described in Gentile Fusillo et al (2019) and converted the magnitudes into units of flux density using the published zero-points for each bandpass.…”

Section: Spectral Energy Distributions and Dusty Infrared Excessesmentioning

confidence: 99%

Five New Post-main-sequence Debris Disks with Gaseous Emission

Dennihy

Lai

et al. 2020

ApJ

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Observations of debris disks, the products of the collisional evolution of rocky planetesimals, can be used to trace planetary activity across a wide range of stellar types. The most common end points of stellar evolution are no exception, as debris disks have been observed around several dozen white dwarf stars. But instead of planetary formation, post-main-sequence debris disks are a signpost of planetary destruction, resulting in compact debris disks from the tidal disruption of remnant planetesimals. In this work, we present the discovery of five new debris disks around white dwarf stars with gaseous debris in emission. All five systems exhibit excess infrared radiation from dusty debris, emission lines from gaseous debris, and atmospheric absorption features indicating ongoing accretion of metal-rich debris. In four of the systems, we detect multiple metal species in emission, some of which occur at strengths and transitions previously unseen in debris disks around white dwarf stars. Our first year of spectroscopic follow-up hints at strong variability in the emission lines that can be studied in the future, expanding the range of phenomena these post-main-sequence debris disks exhibit.

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Section: Spectral Energy Distributions and Dusty Infrared Excessesmentioning

confidence: 99%

Five New Post-main-sequence Debris Disks with Gaseous Emission

Dennihy

Lai

et al. 2020

ApJ

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“…This is one of the most highly metal-polluted white dwarfs known . However, archival 2010 and 2013 adaptive optics images from the VLT reveal the presence of a background source within 0.4 arcsec of the star (Dennihy et al 2017). This calls into question the nature of the observed infrared excess, and it is unclear to what extend the faint background source -detected so far only in the J-band -contributes to the SED at IRAC wavelengths.…”

Section: Notes On Individual Objectsmentioning

confidence: 99%

The unbiased frequency of planetary signatures around single and binary white dwarfs using Spitzer and Hubble

Wilson

Farihi

Gänsicke

et al. 2019

Monthly Notices of the Royal Astronomical Society

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This paper presents combined Spitzer IRAC and Hubble COS results for a double-blind survey of 195 single and 22 wide binary white dwarfs for infrared excesses and atmospheric metals. The selection criteria include cooling ages in the range 9 to 300 Myr, and hydrogenrich atmospheres so that the presence of atmospheric metals can be confidently linked to ongoing accretion from a circumstellar disc. The entire sample has infrared photometry, whereas 168 targets have corresponding ultraviolet spectra. Three stars with infrared excesses due to debris discs are recovered, yielding a nominal frequency of 1.5 +1.5 −0.5 per cent, while in stark contrast, the fraction of stars with atmospheric metals is 45 ± 4 per cent. Thus, only one out of 30 polluted white dwarfs exhibits an infrared excess at 3-4 µm in IRAC photometry, which reinforces the fact that atmospheric metal pollution is the most sensitive tracer of white dwarf planetary systems. The corresponding fraction of infrared excesses around white dwarfs with wide binary companions is consistent with zero, using both the infrared survey data and an independent assessment of potential binarity for well-established dusty and polluted stars. In contrast, the frequency of atmospheric pollution among the targets in wide binaries is indistinct from apparently single stars, and moreover the multiplicity of polluted white dwarfs in a complete and volume-limited sample is the same as for field stars. Therefore, it appears that the delivery of planetesimal material onto white dwarfs is ultimately not driven by stellar companions, but by the dynamics of planetary bodies.

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“…c This object has Spitzer photometry. However, there is a red background object within 1 arcsec and the photometry is likely to be contaminated (Dennihy et al 2017).…”

Section: Hst/cosmentioning

confidence: 99%

Compositions of Planetary Debris around Dusty White Dwarfs

Dufour²,

Klein³

et al. 2019

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The photospheres of some white dwarfs are "polluted" by accretion of material from their surrounding planetary debris. White dwarfs with dust disks are often heavily polluted and high-resolution spectroscopic observations of these systems can be used to infer the chemical compositions of extrasolar planetary material. Here, we report spectroscopic observation and analysis of 19 white dwarfs with dust disks or candidate disks. The overall abundance pattern very much resembles that of bulk Earth and we are starting to build a large enough sample to probe a wide range of planetary compositions. We found evidence for accretion of Fe-rich material onto two white dwarfs as well as O-rich but H-poor planetary debris onto one white dwarf. In addition, there is a spread in Mg/Ca and Si/Ca ratios and it cannot be explained by differential settling or igneous differentiation. The ratios appear to follow an evaporation sequence. In this scenario, we can constrain the mass and number of evaporating bodies surrounding polluted white dwarfs.

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WIRED for EC: New White Dwarfs with WISE Infrared Excesses and New Classification Schemes from the Edinburgh–Cape Blue Object Survey

Cited by 24 publications

References 86 publications

Five New Post-main-sequence Debris Disks with Gaseous Emission

Five New Post-main-sequence Debris Disks with Gaseous Emission

The unbiased frequency of planetary signatures around single and binary white dwarfs using Spitzer and Hubble

Compositions of Planetary Debris around Dusty White Dwarfs

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