Affiliation
American Association of Variable Star Observers (AAVSO)
Sun, 07/16/2017 - 00:03
Observations by AAVSO member Ed Wiley appear to show a deep fade of the high-latitude YSO V1117 Herculis. The fade (if confirmed) is consistent with the rough period of just over 400 days this object exhibits. Fades of V1117 Her have shown a tendency to increasingly faint minima over time which may represent activity in the planetesimal clump(s), so observations at such times are increasingly valuable!
Some recent Obs:
Jun 26 12.6 vis
Jul 12 12.7V
Jul 15 14.6V
Bearing in mind the above description of this star's activity, we may even expect to see further fading. I have submitted extra comparison stars to magnitude 16.4v to the sequence team.
Looks like it might be a double fade, but I only have one data point. A time series taken night of 31 July will be processed soon.
Ed
Masayuki Moriyama (Nagasaki, Japan) had V1117 Her at 14.1V on Jly 28.554. This is unusual indeed, fading so soon after the previous short duration event.
Gary
Yes Gary, and I have just (literally) heard from Ed Wiley which confirms that. Actually I've also just taken a look at the long-term behaviour and these 'secondary' fades are not that uncommon, and also seem to be fainter than the preceding ones.
Mike,
I think the behaviour is changing then. I have data going back to 2004, and certainly any second fading (when occuring) have not been as deep as the preceding one.
The Japanese will have data on this object too. Be good to see that I think!
Gary
So ... The time series, which is somewhat difficient in B and I due to low SNR of the comps, shows a bit of variation. Being new to YSOs I am in no position to judge whether this means something or not. Question is: Should I try for some additional times sereies data or simply continue to monitor each observable night?
Ed
ps, we will probably be socked in for the next few days, but I do have one additional run (point estaimtes) to process.
Last nights observation has V1117 Her back at maximum - Aug 05 21h 44m UT 12.6 vis.
Gary
AAVSO Alert Notice 590 announces a request for ongoing observations of V1117 Her. Please see the notice for details and observing instructions. Many thanks!
Good observing,
Elizabeth Waagen, AAVSO HQ
Hi,
The V117 Her alert notice mentions: "B and Ic bands are specially welcome". But the related area photometry tables charts in AVVSO database shows just V and B-V. So where can I find B and Ic bands photometry tables for this area that I can ?
Thanks!
Use the VSP tool on the AAVSO home page to "Create a finder chart" for V1117 Her. By default, the photometry table for this chart will show only the V comp information. Then, use the link just above the chart to "Plot another chart".
Scroll down to the bottom of the next window. Select the filters you want to use and replot the chart. The photometry table for the new chart will contain the information for the filters you selected.
Phil
Got it. Thanks. Jose Luis.
This peculiar object has just emerged from another fade, and all observers are encouraged to follow this star. A quick naked-eye glance at the recent lightcurve suggests that the gap between fades is lessening. This recent fade was not as deep as usual but given past behaviour this may just be the precursor to a deeper dimming. Whatever is happening there is mysterious stuff!
V1117 Her is bright enough for my ALPY spectrograph: see attached rectified spectra from UT 2020-05-22 and -23 (continuum =1, curves are offset for clarity). In an interval of just one day, the H-alpha emission seems to have strengthened noticeably, H-beta and -gamma absorption weakened.
A year or so ago, James Foster watched this star at similar resolution, and also saw pretty wild changes in spectrum over intervals of just a few days (his spectra are in the BAA database).
I'll keep watching ...
Bob B.
Great to see people following this across a wide range of wavebands!
This is a truly interesting target!
It will be interesting to see in another 400 days what comes of this...