Question.If the star has been long term dimming, what is the 100% flux level they are using as the benchmark? The latest updates show 99.5% flux or thereabouts, but what is that measured against? The flux when Kepler first started observing the star? The flux from May? Because presumably this benchmark level should have been steadily declining, if the star is gradually dimming.
Tabetha Boyajian @tsboyajianDownloaded new data just before wifi fail (so no blog post today). here are the latest #TabbysStar obs
About the 15 July report. Flux looks pretty constant (with a 100 days gap) before day 500 after which it gets lower. But after day 600 the overwhelming majority of observation s are above the fitted curve. Is it really warranted to fit one decreasing curve over the entire period? There's no astrophysical model motivating fitting this particular "functional form" of smooth dimming.
Hi everyone, Below is the graph with today's update. Note: on June 26 (~45 on the x-axis) and after, there have been two 40cm telescopes at each of the LCO stations (OGG and TFN) taking observations of our star (instead of one at each station). Previously posted light curves were generated without this data taken from the second set of telescopes. However, we have now collected enough data to verify that there is consistency with the two new telescopes compared to the ones that we have been using. So the light curve below now includes the "new", old data, combined with the data set that you are accustomed to seeing. The most recent data (there has been bad weather at OGG) look to be fairly consistent with normal brightness (i.e., the error bars on the two, right-most, blue points touch the dotted horizontal line at 1.0). This seems to indicate that the ~2 week long, 0.5% dip is nearing its end. However, given the unpredictable nature of this object, I hesitate to make that official call just yet. Im also torn on whether we should christen these small 0.5% dips, or save the names for just the bigger ones. We'll have to make a decision on this before too long though! Lastly, we continue to work on the Elsie detection paper. Alas, these things (science in general) always take longer than expected. I hope it is not terribly discouraging to you, and I promise that you will be the first to hear when things finalize. ~Tabby and team
[Orig: July, 20 2017] Hi everyone, Below is the newest light curve. Again, the weather was bad at OGG, but observations at TFN continue. I had previously commented that the two TFN observations ~70 on the x-axis could indicate a return to normal (the error bars crossing the dotted line at 1.0). However, perhaps this was a premature conclusion, as they are also in agreement with the 0.5% flux decrement over the past few weeks (note that compared to other measurements, the error bars on these points are somewhat larger). Got to run for now, more later! ~Tabby and team
[Orig: July, 23 2017] Hi everyone, Excuse the break in frequent posts, Ive been traveling. I also forgot to hit "publish" for the last update (38/n), so this is the updated post with the newest light curve as of 2 hours ago. More later! ~Tabby and team
I agree it's too early to conclude there's a clear trend without cherrypicking the desired points. Considering the last measurements seem to have stabilized, I hope this week we'll see whether the star returns back towards normal, stays at a current level, or continues to dim.However, should the measurements follow the 'accelerated dimming' graph, how long would it take for that hypothesis (or does the inferred formula make it a theory?) to be credible enough to warrant time on the bigger telescopes for a detailed study over many wavelengths to see if there's more dimming in certain wavelengths? The previous request was rejected because Tabby's team was unable to specify the specific time of the measurements. If a new proposal would ask to take measurements now, and again in six months for comparison, that might be specific enough to be accepted.Considering we're probably in for the long haul, does anyone know if there's a limit on how long the two observatories can take measurements with the available funding? Or was the funding required for Tabby's team and not for time on these two telescopes?
Especially since on the 600 day view (two clips up) it's apparent that there are only two cluster of data points, so really statistically all we have is that the flux today, if you low-pass the shorter "weekish" events, is lower than it was some 300 days ago.There is no reason to think that this is part of downward trend, and doubly no reason to think that this is part of an accelerating downward trend.