June 8, 2021
AAVSO Forum threads (scroll to the bottom of a thread for latest posts):
- Campaigns and Observation Reports: https://www.aavso.org/fade-v1117-her (goes to YSO forum thread)
- Young Stellar Objects (YSO): https://www.aavso.org/fade-v1117-her
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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.
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