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http://hdl.handle.net/20.500.12386/23382
Title: | FUV Variability of HD 189733. Is the Star Accreting Material From Its Hot Jupiter? | Authors: | PILLITTERI, Ignazio Francesco MAGGIO, Antonio MICELA, Giuseppina SCIORTINO, Salvatore Wolk, S. J. Matsakos, T. |
Issue Date: | 2015 | Journal: | THE ASTROPHYSICAL JOURNAL | Number: | 805 | Issue: | 1 | First Page: | 52 | Abstract: | Hot Jupiters are subject to strong irradiation from their host stars and, as a consequence, they do evaporate. They can also interact with the parent stars by means of tides and magnetic fields. Both phenomena have strong implications for the evolution of these systems. Here we present time-resolved spectroscopy of HD 189733 observed with the Cosmic Origins Spectrograph on board Hubble Space Telescope (HST). The star has been observed during five consecutive HST orbits, starting at a secondary transit of the planet (φ ∼ 0.50-0.63). Two main episodes of variability of ion lines of Si, C, N, and O are detected, with an increase of line fluxes. The Si iv lines show the highest degree of variability. The far-ultraviolet variability is a signature of enhanced activity in phase with the planet motion, occurring after the planet egress, as already observed three times in X-rays. With the support of MHD simulations, we propose the following interpretation: a stream of gas evaporating from the planet is actively and almost steadily accreting onto the stellar surface, impacting at 70{}^\circ -90{}^\circ ahead of the subplanetary point. | Acknowledgments: | I.P. is grateful to H. M. Günther for the help and the discussion of the results. I.P. acknowledges financial support from the European Union Seventh Framework Programme (FP7/2007–2013) under grant agreement No. 267251 Astronomy Fellowships in Italy (AstroFIt). T.M. was supported in part by NASA ATP grant NNX13AH56G. The simulation was carried out with resources provided by the University of Chicago Research Computing Center. This work is based on observations made with the NASA/ESA Hubble Space Telescope , obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program #12984. Support for program #12984 was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. Facilities: HST (COS) . | URI: | http://hdl.handle.net/20.500.12386/23382 | URL: | https://iopscience.iop.org/article/10.1088/0004-637X/805/1/52 | ISSN: | 0004-637X | DOI: | 10.1088/0004-637X/805/1/52 | Bibcode ADS: | 2015ApJ...805...52P | Fulltext: | open |
Appears in Collections: | 1.01 Articoli in rivista |
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Pillitteri_2015_ApJ_805_52.pdf | pdf editoriale | 2.31 MB | Adobe PDF | View/Open |
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