Search Results - "KOESTER, D"

Cool DZ white dwarfs II: compositions and evolution of old remnant planetary systems by Hollands, M A, Gänsicke, B T, Koester, D

“…Abstract In a previous study, we analysed the spectra of 230 cool (Teff < 9000 K) white dwarfs exhibiting strong metal contamination, measuring abundances for…”
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Evidence for Water in the Rocky Debris of a Disrupted Extrasolar Minor Planet by Farihi, J., Gänsicke, B. T., Koester, D.

“…The existence of water in extrasolar planetary systems is of great interest because it constrains the potential for habitable planets and life. We have…”
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New white dwarf and subdwarf stars in the Sloan Digital Sky Survey Data Release 12 by Kepler, S. O., Pelisoli, I., Koester, D., Ourique, G., Romero, A. D., Reindl, N., Kleinman, S. J., Eisenstein, D. J., Valois, A. D. M., Amaral, L. A.

“…We report the discovery of 6576 new spectroscopically confirmed white dwarf and subdwarf stars in the Sloan Digital Sky Survey Data Release 12. We obtain T…”
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New white dwarf stars in the Sloan Digital Sky Survey Data Release 10 by Kepler, S O, Pelisoli, I, Koester, D, Ourique, G, Kleinman, S J, Romero, A D, Nitta, A, Eisenstein, D J, Costa, J E S, Kuelebi, B, Jordan, S, Dufour, P, Giommi, Paolo, Rebassa-Mansergas, Alberto

“…We report the discovery of 9088 new spectroscopically confirmed white dwarfs and subdwarfs in the Sloan Digital Sky Survey Data Release 10. We obtain T..., log…”
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Ancient Planetary Systems are Orbiting a Large Fraction of White Dwarf Stars by Zuckerman, B, Melis, C, Klein, B, Koester, D, Jura, M

“…Infrared studies have revealed debris likely related to planet formation in orbit around {approx}30% of youthful, intermediate mass, main-sequence stars. We…”
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The chemical diversity of exo-terrestrial planetary debris around white dwarfs by Gänsicke, B. T., Koester, D., Farihi, J., Girven, J., Parsons, S. G., Breedt, E.

“…We present Hubble Space Telescope (HST) ultraviolet spectroscopy of the white dwarfs PG 0843+516, PG 1015+161, SDSS 1228+1040, and GALEX 1931+0117, which…”
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Likely detection of water-rich asteroid debris in a metal-polluted white dwarf by Raddi, R., Gänsicke, B. T., Koester, D., Farihi, J., Hermes, J. J., Scaringi, S., Breedt, E., Girven, J.

“…The cool white dwarf SDSS J124231.07+522626.6 exhibits photospheric absorption lines of eight distinct heavy elements in medium resolution optical spectra,…”
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The sdA problem – I. Physical properties by Pelisoli, Ingrid, Kepler, S O, Koester, D

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The sdA problem – III. New extremely low-mass white dwarfs and their precursors from Gaia astrometry by Pelisoli, Ingrid, Bell, Keaton J, Kepler, S O, Koester, D

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The composition of a disrupted extrasolar planetesimal at SDSS J0845+2257 (Ton 345) by Wilson, D. J., Gänsicke, B. T., Koester, D., Toloza, O., Pala, A. F., Breedt, E., Parsons, S. G.

“…We present a detailed study of the metal-polluted DB white dwarf SDSS J0845+2257 (Ton 345). Using high-resolution Hubble Space Telescope/Cosmic Origins…”
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The incidence of magnetic fields in cool DZ white dwarfs by Hollands, M. A., Gänsicke, B. T., Koester, D.

“…Little is known about the incidence of magnetic fields among the coolest white dwarfs. Their spectra usually do not exhibit any absorption lines as the…”
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Chemical Abundances in the Externally Polluted White Dwarf GD 40: Evidence of a Rocky Extrasolar Minor Planet by Klein, B, Jura, M, Koester, D, Zuckerman, B, Melis, C

“…We present Keck/High Resolution Echelle Spectrometer data with model atmosphere analysis of the helium-dominated polluted white dwarf GD 40, in which we…”
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Spectral analysis of cool white dwarfs accreting from planetary systems: from the ultraviolet to the optical by Hollands, M A, Tremblay, P-E, Gänsicke, B T, Koester, D

“…ABSTRACT The accretion of planetary debris into the atmospheres of white dwarfs leads to the presence of metal lines in their spectra. Cool metal-rich white…”
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Partly burnt runaway stellar remnants from peculiar thermonuclear supernovae by Raddi, R, Hollands, M A, Koester, D, Hermes, J J, Gänsicke, B T, Heber, U, Shen, K J, Townsley, D M, Pala, A F, Reding, J S, Toloza, O F, Pelisoli, I, Geier, S, Gentile Fusillo, N P, Munari, U, Strader, J

“…Abstract We report the discovery of three stars that, along with the prototype LP 40−365, form a distinct class of chemically peculiar runaway stars that are…”
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Further Insight on the Hypervelocity White Dwarf, LP 40-365 (GD 492): A Nearby Emissary from a Single-degenerate Type Ia Supernova by Raddi, R., Hollands, M. A., Koester, D., Gänsicke, B. T., Fusillo, N. P. Gentile, Hermes, J. J., Townsley, D. M.

“…The recently discovered hypervelocity white dwarf LP 40−365 (aka GD 492) has been suggested as the outcome of the failed disruption of a white dwarf in a…”
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Magnetic white dwarf stars in the Sloan Digital Sky Survey by Kepler, S. O., Pelisoli, I., Jordan, S., Kleinman, S. J., Koester, D., Külebi, B., Peçanha, V., Castanheira, B. G., Nitta, A., Costa, J. E. S., Winget, D. E., Kanaan, A., Fraga, L.

“…To obtain better statistics on the occurrence of magnetism among white dwarfs, we searched the spectra of the hydrogen atmosphere white dwarf stars (DAs) in…”
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Cool DZ white dwarfs – I. Identification and spectral analysis by Hollands, M. A., Koester, D., Alekseev, V., Herbert, E. L., Gänsicke, B. T.

“…Abstract White dwarfs with metal lines in their spectra act as signposts for post-main-sequence planetary systems. Searching the Sloan Digital Sky Survey…”
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The sdA problem – II. Photometric and spectroscopic follow-up by Pelisoli, Ingrid, Kepler, S O, Koester, D, Castanheira, B G, Romero, A D, Fraga, L

“…ABSTRACT The spectral classification ‘subdwarf A’ (sdA) is given to stars showing H-rich spectra and sub-main-sequence surface gravities, but effective…”
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Unusual Abundances from Planetary System Material Polluting the White Dwarf G238-44 by Johnson, Ted M, Klein, Beth L., Koester, D., Melis, Carl, Zuckerman, B., Jura, M.

“…Abstract Ultraviolet and optical spectra of the hydrogen-dominated atmosphere white dwarf star G238-44 obtained with FUSE, Keck/HIRES, HST/COS, and HST/STIS…”
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DA white dwarfs in Sloan Digital Sky Survey Data Release 7 and a search for infrared excess emission by Girven, J., Gänsicke, B. T., Steeghs, D., Koester, D.

“…We present a method which uses colour-colour cuts on the Sloan Digital Sky Survey (SDSS) photometry to select white dwarfs with hydrogen-rich (DA) atmospheres…”
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