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Near-Infrared Photometric Monitoring of a Pre-Main-Sequence Object KH 15D

Nobuhiko Kusakabe·Motohide Tamura·Yasushi Nakajima·Ryo Kandori·Akika Ishihara·Tetsuya Nagata·Takahiro Nagayama·Shogo Nishiyama·Daisuke Baba·Shuji Sato·Koji Sugitani·Edwin L. Turner·Lyu Abe·Hiroshi Kimura·Tetsuo Yamamoto
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Abstract

An extensive photometric monitoring of KH 15D, an enigmatic variable in the young star cluster NGC 2264, has been conducted. Simultaneous and accurate near-infrared (JHKs-bands) photometry is presented between 2003 December and 2005 March covering most of the variable phase. The infrared variability is characterized by large-amplitude and long-lasting eclipse, as observed at optical. The period of variability is 48.3 +/- 0.2 days, the maximum photometric amplitude of variability is ~4.2 mag, and the eclipse duration is \~0.5 in phase units. These are consistent with the most recent period, amplitude, and duration at optical. The blueing of the J-H color (~0.16 mag) during the eclipse, which has been suggested before, is unambiguously confirmed; a similar blueing at H-Ks is less clear but is probably present at a similar level. The overall shape of the JHKs light curves is very similar to the optical one, including a fair time-symmetry and a less stable flux during the eclipse with a slight hump near the zero phase. Most of these variability features of KH 15D observed at near-infrared wavelengths can be explained with the recent model employing an eclipse by the inclined, precessing disk and an outer scattering region around a pre-main-sequence binary.

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Nobuhiko Kusakabe, Motohide Tamura, Yasushi Nakajima, Ryo Kandori, Akika Ishihara, Tetsuya Nagata, Takahiro Nagayama, Shogo Nishiyama, Daisuke Baba, Shuji Sato, Koji Sugitani, Edwin L. Turner, Lyu Abe, Hiroshi Kimura, Tetsuo Yamamoto. 2005-09-14. Near-Infrared Photometric Monitoring of a Pre-Main-Sequence Object KH 15D. https://doi.org/10.1086/497912

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