Currie, Thayne and Marois, Christian and Cieza, Lucas and Mulders, Gijs D. and Lawson, Kellen and Caceres, Claudio and Rodriguez-Ruiz, Dary and Wisniewski, John and Guyon, Olivier and Brandt, Timothy D. and Kasdin, N. Jeremy and Groff, Tyler D. and Lozi, Julien and Chilcote, Jeffrey and Hodapp, Klaus and Jovanovic, Nemanja and Martinache, Frantz and Skaf, Nour and Lyra, Wladimir and Tamura, Motohide and Asensio-Torres, Ruben and Dong, Ruobing and Grady, Carol and Gerard, Benjamin and Fukagawa, Misato and Hand, Derek and Hayashi, Masahiko and Henning, Thomas and Kudo, Tomoyuki and Kuzuhara, Masayuki and Kwon, Jungmi and McElwain, Michael W. and Uyama, Taichi (2019) No Clear, Direct Evidence for Multiple Protoplanets Orbiting LkCa 15: LkCa 15 bcd are Likely Inner Disk Signals. The Astrophysical Journal, 877 (1). L3. ISSN 2041-8213
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Abstract
Two studies utilizing sparse aperture-masking (SAM) interferometry and Hα differential imaging have reported multiple Jovian companions around the young solar-mass star, LkCa 15 (LkCa 15 bcd): the first claimed direct detection of infant, newly formed planets ("protoplanets"). We present new near-infrared direct imaging/spectroscopy from the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system coupled with Coronagraphic High Angular Resolution Imaging Spectrograph (CHARIS) integral field spectrograph and multi-epoch thermal infrared imaging from Keck/NIRC2 of LkCa 15 at high Strehl ratios. These data provide the first direct imaging look at the same wavelengths and in the same locations where previous studies identified the LkCa 15 protoplanets, and thus offer the first decisive test of their existence. The data do not reveal these planets. Instead, we resolve extended emission tracing a dust disk with a brightness and location comparable to that claimed for LkCa 15 bcd. Forward-models attributing this signal to orbiting planets are inconsistent with the combined SCExAO/CHARIS and Keck/NIRC2 data. An inner disk provides a more compelling explanation for the SAM detections and perhaps also the claimed Hα detection of LkCa 15 b. We conclude that there is currently no clear, direct evidence for multiple protoplanets orbiting LkCa 15, although the system likely contains at least one unseen Jovian companion. To identify Jovian companions around LkCa 15 from future observations, the inner disk should be detected and its effect modeled, removed, and shown to be distinguishable from planets. Protoplanet candidates identified from similar systems should likewise be clearly distinguished from disk emission through modeling.
Item Type: | Article |
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Subjects: | Eprint Open STM Press > Physics and Astronomy |
Depositing User: | Unnamed user with email admin@eprint.openstmpress.com |
Date Deposited: | 02 Jun 2023 08:13 |
Last Modified: | 12 Jan 2024 07:18 |
URI: | http://library.go4manusub.com/id/eprint/574 |