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    Spectro-astrometry of LkCa 15 with X-Shooter: Searching for emission from LkCa 15b

    Whelan, Emma and Huélamo, N. and Alcalá, J.M. and Lillo-Box, J. and Bouy, H. and Barrado, D. and Bouvier, J. and Merin, B. (2015) Spectro-astrometry of LkCa 15 with X-Shooter: Searching for emission from LkCa 15b. Astronomy & Astrophysics, 579 (A48). ISSN 0004-6361

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    Planet formation is one explanation for the partial clearing of dust observed in the disks of some T Tauri stars. Indeed studies using state-of-the-art high angular resolution techniques have very recently begun to observe planetary companions in these so-called transitional disks. The goal of this work is to use spectra of the transitional disk object LkCa 15 obtained with X-Shooter on the Very Large Telescope to investigate the possibility of using spectro-astrometry to detect planetary companions to T Tauri stars. It is argued that an accreting planet should contribute to the total emission of accretion tracers such as Hα and therefore planetary companions could be detected with spectro-astrometry in the same way as it has been used to detect stellar companions to young stars. A probable planetary-mass companion was recently detected in the disk of LkCa 15. Therefore, it is an ideal target for this pilot study. We studied several key accretion lines in the wavelength range 300 nm to 2.2 μm with spectro-astrometry. While no spectro-astrometric signal is measured for any emission lines, the accuracy achieved in the technique is used to place an upper limit on the contribution of the planet to the flux of the Hα, Paγ, and Paβ lines. The derived upper limits on the flux allow an upper limit of the mass accretion rate, log (Ṁacc) = −8.9 to −9.3 for the mass of the companion between 6 MJup and 15 MJup, respectively, to be estimated (with some assumptions).

    Item Type: Article
    Additional Information: *Based on Observations collected with X-Shooter at the Very Large Telescope on Cerro Paranal (Chile), operated by the European Southern Observatory (ESO). Program ID: 288.C-5013(A).
    Keywords: stars: low-mass; binaries: close; planets and satellites: formation;
    Academic Unit: Faculty of Science and Engineering > Experimental Physics
    Item ID: 9879
    Depositing User: Emma Whelan
    Date Deposited: 04 Sep 2018 16:08
    Journal or Publication Title: Astronomy & Astrophysics
    Publisher: EDP Sciences
    Refereed: Yes
    Use Licence: This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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