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158 results on '"Debes, John H."'

152. Characterizing Dusty Debris Disks with the Gemini Planet Imager

Author

Chen, Christine, Pauline Arriaga, Bruzzone, Sebastian, Choquet, Elodie, Debes, John H., Donaldson, Jessica, Draper, Zachary, Duchene, Gaspard, Esposito, Thomas, Fitzgerald, Michael P., Golimowski, David A., Hines, Dean C., Hinkley, Sasha, Hughes, A. Meredith, Kalas, Paul, Kolokolova, Ludmilla, Lawler, Samantha, Matthews, Brenda C., Mazoyer, Johan, Metchev, Stanimir A., Millar-Blanchaer, Max, Moro-Martin, Amaya, Nesvold, Erika, Padgett, Deborah, Patience, Jenny, Perrin, Marshall D., Pueyo, Laurent, Rantakyro, Fredrik, Rodigas, Timothy, Schneider, Glenn, Soummer, Remi, Song, Inseok, Stark, Chris, Weinberger, Alycia J., and Wilner, David J.

154. A SUBTLE INFRARED EXCESS ASSOCIATED WITH A YOUNG WHITE DWARF IN THE EDINBURGH-CAPE BLUE OBJECT SURVEY

Author

Dunlap, Dennihy, Clemens, Debes, John H., Dufour, and Teske, Johanna K.

Subjects
13. Climate action
Abstract

We report the discovery of a subtle infrared excess associated with the young white dwarf EC 05365–4749 at 3.35 and 4.6 μ m. Follow-up spectroscopic observations are consistent with a hydrogen atmosphere white dwarf of effective temperature 22,800 K and log [ g (cm s{sup −2})] = 8.19. High-resolution spectroscopy reveals atmospheric metal pollution with logarithmic abundances of [Mg/H] = −5.36 and [Ca/H] = −5.75, confirming the white dwarf is actively accreting from a metal-rich source with an intriguing abundance pattern. We find that the infrared excess is well modeled by a flat, opaque debris disk, though disk parameters are not well constrained by the small number of infrared excess points. We further demonstrate that relaxing the assumption of a circular dusty debris disk to include elliptical disks expands the widths of acceptable disks, adding an alternative interpretation to the subtle infrared excesses commonly observed around young white dwarfs.

158. Spitzer Follow-up of Extremely Cold Brown Dwarfs Discovered by the Backyard Worlds: Planet 9 Citizen Science Project.

Author

Meisner, Aaron M., Faherty, Jacqueline K., Kirkpatrick, J. Davy, Schneider, Adam C., Caselden, Dan, Gagné, Jonathan, Kuchner, Marc J., Burgasser, Adam J., Casewell, Sarah L., Debes, John H., Artigau, Étienne, Gagliuffi, Daniella C. Bardalez, Logsdon, Sarah E., Kiman, Rocio, Allers, Katelyn, Hsu, Chih-chun, Wisniewski, John P., Allen, Michaela B., Beaulieu, Paul, and Colin, Guillaume

Subjects
*BROWN dwarf stars, *CITIZEN science, *ASTROMETRY, *DWARF stars, *WHITE dwarf stars, *FRONT yards & backyards
Abstract

We present Spitzer follow-up imaging of 95 candidate extremely cold brown dwarfs discovered by the Backyard Worlds: Planet 9 citizen science project, which uses visually perceived motion in multiepoch Wide-field Infrared Survey Explorer (WISE) images to identify previously unrecognized substellar neighbors to the Sun. We measure Spitzer [3.6]–[4.5] color to phototype our brown dwarf candidates, with an emphasis on pinpointing the coldest and closest Y dwarfs within our sample. The combination of WISE and Spitzer astrometry provides quantitative confirmation of the transverse motion of 75 of our discoveries. Nine of our motion-confirmed objects have best-fit linear motions larger than 1″ yr−1; our fastest-moving discovery is WISEA J155349.96+693355.2 (μ ≈ 2.″15 yr−1), a possible T-type subdwarf. We also report a newly discovered wide-separation (∼400 au) T8 comoving companion to the white dwarf LSPM J0055+5948 (the fourth such system to be found), plus a candidate late T companion to the white dwarf LSR J0002+6357 at 5.′5 projected separation (∼8700 au if associated). Among our motion-confirmed targets, five have Spitzer colors most consistent with spectral type Y. Four of these five have exceptionally red Spitzer colors suggesting types of Y1 or later, adding considerably to the small sample of known objects in this especially valuable low-temperature regime. Our Y dwarf candidates begin bridging the gap between the bulk of the Y dwarf population and the coldest known brown dwarf. [ABSTRACT FROM AUTHOR]

Published
2020
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