Second Outburst of the Yellow Symbiotic Star LT Delphini. (arXiv:1906.10985v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Ikonnikova_N/0/1/0/all/0/1">N.P. Ikonnikova</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Komissarova_G/0/1/0/all/0/1">G.V. Komissarova</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Arkhipova_V/0/1/0/all/0/1">V.P. Arkhipova</a>
We present the results of our photoelectric $UBV$ observations of the yellow
symbiotic star LT Del over 2010-2018. The binary system LT Del, which consists
of a bright K giant and a compact hot star with a temperature of $sim$100 000
K, has an orbital period of 476 days. In 2017 the variable experienced a second
low-amplitude ($Delta Vsim 0.^{m}7$) outburst in the history of its studies
whose maximum occurred at an orbital phase of 0.15$pm$0.05. The outburst
duration was $sim$60 days. The $B-V$ and $U-B$ colors in the outburst became
noticeably bluer. A difference in the photometric behavior of the star in the
1994 and 2017 outburst has been detected. In the orbital cycle preceding the
2017 outburst a secondary minimum with a depth of $0.^{m}15$ and $0.^{m}20$
appeared in the $B$ and $V$ light curves, respectively, whose cause is
discussed. The phase light and color curves are presented and explained; the
position of the star on the color-color diagram is interpreted. We have
estimated the parameters of the cool and hot components of the system based on
the distance determination from Gaia DR2.
We present the results of our photoelectric $UBV$ observations of the yellow
symbiotic star LT Del over 2010-2018. The binary system LT Del, which consists
of a bright K giant and a compact hot star with a temperature of $sim$100 000
K, has an orbital period of 476 days. In 2017 the variable experienced a second
low-amplitude ($Delta Vsim 0.^{m}7$) outburst in the history of its studies
whose maximum occurred at an orbital phase of 0.15$pm$0.05. The outburst
duration was $sim$60 days. The $B-V$ and $U-B$ colors in the outburst became
noticeably bluer. A difference in the photometric behavior of the star in the
1994 and 2017 outburst has been detected. In the orbital cycle preceding the
2017 outburst a secondary minimum with a depth of $0.^{m}15$ and $0.^{m}20$
appeared in the $B$ and $V$ light curves, respectively, whose cause is
discussed. The phase light and color curves are presented and explained; the
position of the star on the color-color diagram is interpreted. We have
estimated the parameters of the cool and hot components of the system based on
the distance determination from Gaia DR2.
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