The critical binary star separation for a planetary system origin of white dwarf pollution

Veras, Dimitri; Xu, Siyi; Rebassa‐Mansergas, A.

doi:10.1093/mnras/stx2141

Cited by 40 publications

(14 citation statements)

References 162 publications

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“…Recent theoretical work has suggested several, long-term dynamical processes involving a binary companion that may significantly Veras et al 2018). Auspiciously, white dwarf stars are highly transparent to companion detection via their Earth-sized radii and blue-peaked stellar continua; only the coldest and lowest mass substellar companions remain out of reach of conventional, ground-based detection ).…”

Section: Binary White Dwarfsmentioning

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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Section: Binary White Dwarfsmentioning

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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“…Twenty different atmospheric metals have been detected, and overall they resemble the bulk Earth in composition (Klein et al 2010;Gänsicke et al 2012;Jura & Young 2014;Wilson et al 2015Wilson et al , 2016Xu et al 2017;Harrison et al 2018;Hollands et al 2018). Nearly all metal pollution has been sought around single white dwarfs, although confident detections can be made in wide binary systems containing a white dwarf (Veras et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Effects of non-Kozai mutual inclinations on two-planet system stability through all phases of stellar evolution

Veras

Georgakarakos²,

Gänsicke

et al. 2018

Monthly Notices of the Royal Astronomical Society

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Previous full-lifetime simulations of single-star multi-planet systems across all phases of stellar evolution have predominately assumed coplanar or nearly-coplanar orbits.Here we assess the consequences of this assumption by removing it and exploring the effect of giant branch mass loss on the stability of two-planet systems with small to moderate non-Kozai (< 40 degrees) relative inclinations. We run nearly 10 4 simulations over 14 Gyr for F-star, A-star and B-star planet hosts, incorporating main sequence stellar masses of 1.5, 2.0, 2.5, 3.0 and 5.0 solar masses, and initial planetary semimajor axis ratios that straddle their three-dimensional Hill stability limits. We find that the near-coplanar assumption can approximate well the stability frequencies and critical separations found for higher inclinations, except around strong mean-motion commensurabilities. Late instabilities -after the star has become a white dwarf -occur throughout the explored mutual inclination range. Consequently, non-Kozai mutual inclination should not be used as a predictive orbital proxy for determining which white dwarf multi-planet systems discovered by Gaia should represent high-priority follow-up targets for the detection of metal pollution and planetary debris discs. † STFC Ernest Rutherford Fellow 1 The exceptions include WD 0806-661b (Luhman et al. 2011) in three flavours, as described below, from: (i) atmospheric metal pollution, (ii) planetary debris discs, and (iii) active exo-minor planets.

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“…White Dwarfs (WD): Recent discoveries of WD debris discs and disintegrating planetesimals have fueled the speculation that planets could be present in WD systems (Loeb & Maoz 2013), (Veras et al 2018). WD exoplanets would have very short (few minutes to tens of minutes) transit duration and very deep (∼ 100 percent for earth size planets) transit depths.…”

Section: Transit Surveysmentioning

confidence: 99%

Building the Evryscope: Hardware Design and Performance

Ratzloff

Law

Fors

et al. 2019

PASP

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The Evryscope is a telescope array designed to open a new parameter space in optical astronomy, detecting short timescale events across extremely large sky areas simultaneously. The system consists of a 780 MPix 22-camera array with an 8150 sq. deg. field of view, 13" per pixel sampling, and the ability to detect objects down to m g 16 in each 2 minute dark-sky exposure. The Evryscope, covering 18,400 sq.deg. with hours of high-cadence exposure time each night, is designed to find the rare events that require all-sky monitoring, including transiting exoplanets around exotic stars like white dwarfs and hot subdwarfs, stellar activity of all types within our galaxy, nearby supernovae, and other transient events such as gamma ray bursts and gravitational-wave electromagnetic counterparts. The system averages 5000 images per night with ∼300,000 sources per image, and to date has taken over 3.0M images, totalling 250TB of raw data. The resulting light curve database has light curves for 9.3M targets, averaging 32,600 epochs per target through 2018. This paper summarizes the hardware and performance of the Evryscope, including the lessons learned during telescope design, electronics design, a procedure for the precision polar alignment of mounts for Evryscope-like systems, robotic control and operations, and safety and performance-optimization systems. We measure the on-sky performance of the Evryscope, discuss its data-analysis pipelines, and present some example variable star and eclipsing binary discoveries from the telescope. We also discuss new discoveries of very rare objects including 2 hot subdwarf eclipsing binaries with late M-dwarf secondaries (HW Vir systems), 2 white dwarf / hot subdwarf short-period binaries, and 4 hot subdwarf reflection binaries. We conclude with the status of our transit surveys, M-dwarf flare survey, and transient detection.

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The critical binary star separation for a planetary system origin of white dwarf pollution

Cited by 40 publications

References 162 publications

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

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

Effects of non-Kozai mutual inclinations on two-planet system stability through all phases of stellar evolution

Building the Evryscope: Hardware Design and Performance

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