WD 1145+017: Optical Activity During 2016-2017 and Limits on the X-Ray Flux

Abstract

WD 1145+017 was observed from 2016 November through 2017 June for the purpose of further characterizing the transit behavior of the dusty debris clouds orbiting this white dwarf. The optical observations were carried out with a small ground-based telescope run by an amateur astronomer, and covered 53 different nights over the 8-month interval. We have found that the optical activity has increased to the highest level observed since its discovery with Kepler K2, with approximately 17% of the optical flux extinguished per orbit. The source exhibits some transits with depths of up to 55% and durations as long as two hours. The dominant period of the orbiting dust clouds during 2016-2017 is 4.49126 hours. We present 'waterfall' images for the entire 2016-2017 and 2015-2016 observing seasons. In addition, the white dwarf was observed with the Chandra X-ray Observatory for 10-ksec on each of four different occasions, separated by about a month each. The upper limit on the average X-ray flux from WD 1145+017 is ~5 x 10^{-15} ergs/cm^2/s (unabsorbed over the range 0.1-100 keV), which translates to an upper limit on the X-ray luminosity, Lx, of ~2 x 10^{28} ergs/s. If Lx = G Mwd Mdot/Rwd, where Mwd and Rwd are the mass and radius of the white dwarf, and Mdot is the accretion rate, then Mdot < 2 x 10^{11} g/s. This is just consistent with the value of Mdot that is inferred from the level of dust activity.

arXiv comment14 pages, 8 figures, submitted to MNRAS

References in corpus (28)

• The UKIRT Infrared Deep Sky Survey (UKIDSS)
• Collisional Plasma Models with APEC/APED: Emission Line Diagnostics of Hydrogen-like and Helium-like Ions
• The Ninth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Baryon Oscillation Spectroscopic Survey
• The Fourth US Naval Observatory CCD Astrograph Catalog (UCAC4)
• A box-fitting algorithm in the search for periodic transits
• A disintegrating minor planet transiting a white dwarf
• The frequency of planetary debris around young white dwarfs
• Ancient planetary systems are orbiting a large fraction of white dwarf stars
• Infrared Signatures of Disrupted Minor Planets at White Dwarfs
• X-ray Emissions from Accreting White Dwarfs: a Review
• 55 Cancri (Copernicus): A Multi-Planet System with a Hot Super-Earth and a Jupiter Analogue
• Debris Disks Around White Dwarfs: The DAZ Connection
• Magnetically Torqued Thin Accretion Disks
• The frequency and infrared brightness of circumstellar discs at white dwarfs
• Evolution of OH and CO-dark Molecular Gas Fraction Across a Molecular Cloud Boundary In Taurus
• Drifting Asteroid Fragments Around WD 1145+017
• High-speed photometry of the disintegrating planetesimals at WD1145+017: evidence for rapid dynamical evolution
• The Frequency of Debris Disks at White Dwarfs
• Deriving an X-ray luminosity function of dwarf novae based on parallax measurements
• Numerical Simulations of Collisional Cascades at the Roche Limits of White Dwarf Stars
• Explaining the variability of WD 1145+017 with simulations of asteroid tidal disruption
• Multiwavelength Transit Observations of the Candidate Disintegrating Planetesimals Orbiting WD 1145+017
• Spectroscopic Evolution of Disintegrating Planetesimals: Minutes to Months Variability in the Circumstellar Gas Associated with WD 1145+017
• WD 1145+017 Photometric Observations During 8 Months of High Activity
• Tilt Angle and Footpoint Separation of Small and Large Bipolar Sunspot Regions Observed with HMI
• Mass and eccentricity constraints on the planetary debris orbiting the white dwarf WD 1145+017
• Magnetospherically-trapped dust and a possible model for the unusual transits at WD 1145+017
• XMM-Newton Observations of the Cataclysmic Variable GW Lib

Cited by in corpus (24)

• I Spy Transits and Pulsations: Empirical Variability in White Dwarfs Using Gaia and the Zwicky Transient Facility
• A White Dwarf with Transiting Circumstellar Material Far Outside the Roche Limit
• Recurring Planetary Debris Transits and Circumstellar Gas around White Dwarf ZTF J0328$-$1219
• Relentless and Complex Transits from a Planetesimal Debris Disk
• Exoplanet recycling in massive white-dwarf debris discs
• Circularization of tidal debris around white dwarfs: implications for gas production and dust variability
• A dearth of small particles in the transiting material around the white dwarf WD 1145+017
• Modeling of the Variable Circumstellar Absorption Features of WD 1145+017
• Fast spectrophotometry of WD 1145+017
• The lifetimes of planetary debris discs around white dwarfs
• Embedding planetesimals into white dwarf discs from large distances
• Orbital relaxation and excitation of planets tidally interacting with white dwarfs
• High-eccentricity migration of planetesimals around polluted white dwarfs
• Shallow Ultraviolet Transits of WD 1145+017
• Near-infrared variability in dusty white dwarfs: tracing the accretion of planetary material
• Survivability of radio-loud planetary cores orbiting white dwarfs
• Occultations from an active accretion disk in a 72 day detached post-Algol system detected by K2
• WD 1145+017: Alternative models of the atmosphere, dust clouds, and gas rings
• Back to "Normal" for the Disintegrating Planet Candidate KIC 12557548 b
• Minimum Orbital Periods of H-Rich Bodies
• Time resolved spectroscopy of dust and gas from extrasolar planetesimals orbiting WD 1145+017
• Planetesimals drifting through dusty and gaseous white dwarf debris discs: Types I, II and III-like migration
• Disruption of exo-asteroids around white dwarfs and the release of dust particles in debris rings in co-orbital motion
• Extrasolar enigmas: from disintegrating exoplanets to exoasteroids