English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

With the recent discovery of transiting planetary material around WD1145+017, a critical target has been identified that links the evolution ofplanetary systems with debris disks and their accretion onto the star. Wepresent a series of observations, five epochs over a year, taken with Keck andthe VLT, which for the first time show variability of circumstellar absorptionin the gas disk surrounding WD 1145+017 on timescales of minutes to months.Circumstellar absorption is measured in more than 250 lines of 14 ions amongten different elements associated with planetary composition, e.g., O, Mg, Ca,Ti, Cr, Mn, Fe, Ni. Broad circumstellar gas absorption with a velocity spreadof 225 km/s is detected, but over the course of a year blue shifted absorptiondisappears while redshifted absorption systematically increases. A correlationof equivalent width and oscillator strength indicates that the gas is nothighly optically thick (median tau approximately 2). We discuss simple modelsof an eccentric disk coupled with magnetospheric accretion to explain the basicobserved characteristics of these high resolution and high signal-to-noiseobservations. Variability is detected on timescales of minutes in the two mostrecent observations, showing a loss of redshifted absorption for tens ofminutes, coincident with major transit events and consistent with gas hiddenbehind opaque transiting material. This system currently presents a uniqueopportunity to learn how the gas causing the spectroscopic, circumstellarabsorption is associated with the ongoing accretion evidenced by photosphericcontamination, as well as the transiting planetary material detected inphotometric observations.

Spectroscopic Evolution of Disintegrating Planetesimals: Minutes to Months Variability in the Circumstellar Gas Associated with WD 1145+017