0 Assigned ID: 1693 ----- Attempting Submission 1 (Wed Mar 21 23:16:44 GMT 2018) ----- HST Phase I Proposal 1693 (apas2047.apt) successfully submitted. Receipt: # 1693-1 ----- Attempting Submission 2 (Thu Mar 22 00:36:20 GMT 2018) ----- For the best data quality, it is strongly recommended that the maximum number of allowed FP-POS positions is used when observing at a given COS CENWAVE setting. See full description for details. As discussed with Nick, we now split the @ 1222A observations across all four FP-POS settings, double-checked the ETC simulations, modified the buffer times accordingly. 583781765 ----- Attempting Submission 1 (Tue May 22 13:51:25 GMT 2018) ----- ----- Attempting Submission 2 (Tue Aug 21 09:39:09 GMT 2018) ----- Using G1300M/1291 so not all FP-POS available. See submission comment for more details. Kuiper belt objects are the best candidate source of water and volatile elements delivered to terrestrial planets early in the solar system. Determining the prevalence of this architecture in the galaxy is fundamental to modelling the frequency of habitable planets. We propose to examine a system showing remarkable water content, and discover the origin of its water-bearing rocky material. White dwarf APASS J2047-1259 exhibits absorption features of both rock-forming and volatile elements. COS Snapshot observations have detected a large oxygen excess, while optical spectra show the extraordinary hydrogen fraction (5% by mass) of the helium atmosphere, beyond explanation by continuous evolution. That the star has undergone accretion is beyond question, but the history of the pollutant material is yet to be determined. A detection of nitrogen would indicate cometary origin, providing firm evidence of hydrogen pollution of white dwarfs from objects formed well beyond the snow line. We apply for five HST orbits in order to be sensitive to relevant abundances of volatiles that would classify the accreted material. We will also gain a precise measurement of the abundance of oxygen and other elements, allowing a confident determination of the composition and oxygen excess of the accreted material, and thus constraining the mass of water accreted by this star. The results will not only impact understandings of white dwarf atmospheric evolution, but will further our knowledge of the ubiquity and history of water in planetary systems around Sun-like stars. The purpose of these COS observations are to obtain a high signal-to-noise ratio of the white dwarf APASS2047, which is accreting volatile rich planetary debris. Key lines for this study are N I 1200A, O I 1150A, and multiple lines of S and P. To maximise the S/N, we use two FP-POS settings @ 1291A, and three @ 1222A. The 1222A observations will extend the wavelength coverage into the red wing of Ly beta, which will provide additional constraints on the effective temperature, and allow to probe for the presence / absence of the quasi-molecular Ly beta line near 1175A. Changes: 21 August 2018: As discussed with Nick, we now split the @ 1222A observations across all four FP-POS settings, double-checked the ETC simulations, modified the buffer times accordingly. Planets and Planet Formation 6 false false true false false false false SUPPORTED STAR DA NO J2000 J2000 GALEX FUV=15.59, observed with COS (LDNU0R010), F(1300A)=3e-14erg/cm2/s/A COS/FUV Spectroscopic No No G130M 1291 The scheduling data was generated by CASM 25.2. 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