Alert Notice 744: V1117 Her observations requested

June 8, 2021

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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 begun another fade. Recent observations by Gary Poyner and myself show the star fading to magnitude 14. This may become a deep fade or possibly a shallower 'precursor' fade as this object sometimes exhibits.

"Observations, both visual and multiwavelength, are encouraged, since the behaviour of this star's historical fading episodes may indicate rapidly-changing evolution of protoplanetary clumps in the circumstellar disc.

"V1117 Her often seems to have these precursory 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 has a range of approximately V = 12.3 - <13.9.

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

Charts: Finder charts with comparison stars 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.

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

Information on submitting observations to the AAVSO may be found at:
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 - Spectroscopy:


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