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Alert Notice 590: V1117 Her observations requested

August 7, 2017: AAVSO Young Stellar Object (YSO) Section leader Michael Poxon (Great Plumstead, Norfolk, UK) requests coverage of the YSO V1117 Her.

He writes: "The peculiar YSO V1117 Herculis has undergone a second, rapid fade and recovery only a few days after its recovery from another rapid fade. Observations, both visual and multiwavelength, are encouraged, since the behaviour of this star's historical fading episodes may indicate rapidly-changing evolution of the protoplanetary clumps in the circumstellar disc.

"V1117 Her often seems to have 'mini-fades' before the main event, but not so often, if at all, afterwards - suggesting maybe asymmetry in the circumstellar clumps. So it may be worth watching for these too.

"Observations in the B and I bands are especially welcome." V band photometry is encouraged, and visual observations are welcome. Observations two-three times per night are requested when the star is active and once per night between episodes of activity.

V1117 Her, which has a range of ~ V = 12.3 - <13.9, was at visual magnitude 12.6 as of 2017 August 5.906 UT, according to an observation by G. Poyner (PYG, Birmingham, England) in the AAVSO International Database.

Coordinates for V1117 Her (2000):   RA 16 39 06.43   Dec. +09 47 55.3

Charts: Finder charts with a comparison star sequence for V1117 Her may be created using the AAVSO Variable Star Plotter (VSP).

Submit observations: Please submit observations to the AAVSO International Database using the name V1117 HER.

V1117 Her is being followed on the Young Stellar Objects (YSO) Forum at https://www.aavso.org/fade-v1117-her.

This AAVSO Alert Notice was compiled by Elizabeth O. Waagen using information provided by Michael Poxon.

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