AAVSO Alert Notice 532 requests multicolor time-series observations of the enigmatic variable KIC 8462852. Please see the Alert Notice for details and instructions.
Many thanks and good observing!
Elizabeth Waagen, AAVSO HQ
I'm getting this message in Vsp: "There were errors in your form. Fix these issues to continue:
- What is the Name, Designation or AUID of the object?: Star 'KIC 08462852' could not be found in our database."
VSX can find KIC 08462852 with or without the leading zero and as long as there are at least the correct number of spaces between the parts of the star name.
However, VSP is sensitive to the leading zero and to the number of spaces. It looked as though you had three or four spaces after KIC, and that caused VSP not to be able to find the star (I tried VSP with the name that way and that's what happened). Also, now that Sebastian has changed the VSX entry, please don't use the leading zero.
Thanks for wanting to observe this interesting star!
I mis-spoke in my previous post. Sebastian did not change the VSX entry for KIC 8462852 (KIC 08462852). The entry was submitted without the leading zero - and, as I was the person who did that, I should have made the Alert Notice conform to that format! My apologies all around.
The Kepler data pages do not use the leading zero and most publications with Kepler data do not use it either.
Since the number of stars reaches 8 digits and SIMBAD's Dictionary of Nomenclature of Celestial Objects shows the format KIC NNNNNNNN, sometimes a leading zero is indeed used. As a result we have a mix in VSX where there are many more stars without the leading zero but this is not something consistent because we usually take the ID from the publications.
We have added the two names now so VSP will make a chart no matter what name you enter.
For other KIC stars, whenever you don't get a chart with one of the name versions try the other one.
Thanks for the clarrification! I'm usually too lazy (and not accurate) to input these Kepler variable names, so I cut & pasted the name directly from the Alert Notice 532; with no leading or following spaces. I tried without the space but did not try without the 0. Although I got a chart uning the object's RA/Dec coordinates, I'd rather have a chart with everything labeled before I reduce the data in Maxim and transform the VBI magnituded in TA. Thanks again!
Will there be any U magnitudes given for the comp stars around KIC 08462852?
I remember reading that it would be desirable to show U to Ic differences in magnitude
to determine whether KIC 08462852 is surrounded by either large or small debris particles.
Los Angeles, CA
Dear AAVSO observers,
I want to express my gratitude for your efforts to monitor the mysterious star KIC 8462852! Your contributions are critical in determining what is causing its unusual variability!
I would like to take a moment to prepare you for when the dipping will happen -- it is fair to say that we have no idea when this could be! The Kepler light curve spanned 4 years, and this object was dipping only for a very small fraction of that time. When the time comes that we observe KIC 8462852 to start dipping again, we will be able to trigger a larger follow up network of observations in order to find out more information on what is causing the dips. However, it is important to remember that by knowing when this object is *not* dipping also provide constraints on the system.
Interesting - your choice of words implies greater confidence in the likelihood of further dimmings than was perhaps apparent in your paper, at least under the comet scenario. Either way, compliments on brewing up such a storm:)
A quick look on
A quick look on LCG for this star shows a 0.2-mag drop in V on Oct 31-Nov-1
Error measures or real drop?
I looked at the light curve that you posted. I also looked at a 30 day light curve, and looked at a light curve in all 4 colors. Also expanded on the night in question. These are the observations made about this data;
1. The observer with the lower light curve, had an observation on 10/25 which was right on the other observers.
2. On 10/30 00:00, there are two observers separated by 0.1 mag, indicating that Transformation may not have been done.
3. If I look at the data on JD 2457327, the lower light curve shows a discontinuity at roughly mid point. This suggests a dec flip perhaps. It also suggests scattered light issues. Since this observer was right on several days earlier, I wonder if there was an interferring moon on the night in question? Just looked up and the full moon was on the night of JD 2457327--ie Oct 31.
4. There is no corroborating data in B, R, or I that also shows the dip.
5. Other data that night at the same time does not show the bias change. Perhaps the questionable data has high extinction compared to the other data.
I don't think this stands up as a real effect. Also remember that this behavior is within +/- .016 mags one sigma (0.1 mag peak to peak) which is about all that can be expected. To do better we would have to have all the data Transformed, Use the exact same comp/ref stars, and reduce stray light to remove dec flip anomalies, check for extinction effects, etc.
The extraordinaty Tabby Boyajian's TED talk on KIC 8462852 is online:
AAVSO observers are mentioned in the end of her talk. Follow-up observing is really important, especially as we try to understand the nature of this object. Please add it in your observing list.
Best wishes - clear skies,
At first I thought (of course) "F-type sprectrum, aperiodic dips, must be another UXOR!", but there doesn't appear to be any IR excess from a disc. Purely on a light-curve basis this looks like a small-amplitude RCB star. How does the spectrum compare as regards elements that could be a source of RCB-type veiling?
Hey, good question!
In the paper (http://arxiv.org/pdf/1509.03622.pdf) We compared this star to a RCB type and found it is inconsistent with our observations of KIC 846.
1) RCB light curve dips are typically quick ingress & slow egress - opposite to what we observe for KIC 846.
2) RCB stars are also a very evolved evolutionary state, meaning that they have low surface gravity which can be seen in the spectrum - the spectrum for KIC 846 tells us the star has not evolved at all.
PS: yes, the lack of IR excess gives trouble to most theories!
AAVSO Alert Notice 542 re-iterates the request for continuing time-series observations of KIC 8462852 = KIC 08462852 (either name may be used to create charts, plot light curves, or submit observations). It also includes the links to the MNRAS paper by Dr. Tabetha Boyajian et al. and to her TED talk.
Elizabeth Waagen, AAVSO HQ
In the second version of the article about discovery Tabby's star there is speculation of a possible 48.4-day periodicity of eclipses
May 4 this year AAVSO observers have detected a new transit. Interestingly, the new transit also in accordance with 48.4-day periodicity of eclipses:
As the 48.4-daily periodicity of work, I think, observers AAVSO should focus specifically on the 48.4-day window to find new transits. Also, and on 24.8-day intervals (some small transits in photometry telescope Kepler observed near half 48.4-day intervals).
Detection frequency of transits probably makes version comet swarm untenable. It remains to three possibilities:
1) Unknown type of periodic variable star
2) Eclipse is a variable dust tail evaporating not-transit planet (like volcanic Jupiter's satellites - Io).
3) Eclipse is a constellation of artificial astroengineering with multiple distance between each other. Like the NASA satellite constellation - A-Train.
The Planet - And it´s orbiting Moon(s)?
To me it is very likely that the data shows the orbiting planet and it´s Moon/Moons which can explain the different signals as the moon (s) orbits the planet, changing orbital positions around the planet and thus giving different profile signals.
To all of the observers who have contributed to this crazy star's light curve for the past 13 months -- THANKS for all your hard work and dedication to the project!
Over the next few weeks, the star will be slipping away from our view. I hope that your observations continue when the star becomes visible again early next year!
And if you are ever in Baton Rouge, LA, feel free to reach out and connect. First drink is on me!
We are requesting for observers at high latitudes to make an extra effort this month - the star is out of reach for most of the world but not for you! Nightly observations in as many filters as you can. Message me if you have any questions and keep up the good work!
I'm at latitude +45 (Atlantic Canada) and am still observing it. Looks like there are only 4 of us in the last month. I am taking B and V. If R and/or I are useful let me know and I'll add them.
--- Dave LDJ
Yes please add the RI filters! The composition of whatever is blocking the light will be wavelength dependent. We can get the most info out of colors that are furthest apart in wavelength. TY!
Is there anyone that might be able to corroborate my data submission on 4/26/17 for this star. Im showing a noticable dip in magnitude on that evening. I'm not sure if this is the tail end of an egress. Any clarification would be appreciated.
I can see it from my home obs for about an hour or so in early mornings for another 2-3 weeks or so.
Can shoot R, G, B or, optionally, 3nm SII, OIII, Ha, or NII as well. Would such short observation time frames be of any value?
I have been observing this star since the beginning of the campaign and just became aware that the two main comp stars are bad! Apparently 000-BLS-549 has been known for some time (even by Tabby!!!) to be a periodic variable of about 16 days (about 0.01 range), but it still remains as a reference star.
How are we to do good work when these major issues aren't fixed after they are known?
Bruce Gary did an analysis of the field the stars he was using, see: http://www.brucegary.net/ts3/RefStarAnal.html
Star 000-BLS-555 also appears bad as there is a trend over several months.
Can we ask the chart team to get this fixed ASAP (with guidance from Gary's analysis)?
Dave Lane (LDJ)
I know the sequence team would be happy to make corrections. Would you please submit a CHET using the "report chart errors" hotspot at the top of the VSP chart request page. There is a link to very detailed instructions on the CHET page.
I found 000-BLS-549 listed as a rotationally variable star in Simbad based on data from Kepler as mentioned on Bruce Gary's page. See attached. However, there is no entry for it as a variable in VSX. I will alert Sebastian Otero about this so that he can verify and update VSX.
I can find no reference to variability of 000-BLS-555 using a positional search in VSX, Simbad or Vizier. If you have data that supports the long term variability of this comp please submit it to have it included as variable in VSX. The procedure for submitting new variables is available through the guidelines link at the bottom of the VSX search page here:
Please excuse the repitition if this procedural stuff is all "old hat" to you.
I will alert Tom Bretl, head of the sequence team, to this issue. He may decide to exclude or replace 000-BLS-555 whether it is accepted as variable or or suspected variable, or not.
For ease of reference, 000-BLS-549 (label 124) corresponds to the star labeled 24 and listed as variable on the Bruce Gary page referenced in Dave's post. 000-BLS-555 (label 128) corresponds to star 20 on Bruce's page which is shown as "bad" and having a trend, but Bruce has included it in the acceptable stars in his plots. Stars 6 and 14 in Bruce's list are also listed as "bad" and having a trend but are included among the acceptable stars as well. Star 12 appears to have a clear but somewhat smaller trend in the plots but is not listed as having a trend or being bad in the table and is included among the acceptable comp stars. Stars 6 and 12 and 14 in Bruce's list are not included among the AAVSO comp stars.
Brad Walter, Sequence Team
Glad the info was helpful. If you were an old hand with the process I didn't want to seem pedantic. I used VSP for years without noticing the link to submitting a chart correction and the procedure for getting a star classified as variable is in the innocuous link, "Guidelines", in small letters at the bottom of the VSX search page. So that info isn't in an obvious place. Otherwise you have to find it on the variable star tab or use website search box and enter something like "new variable star" or "report new variable star." It isn't something that jumps out at you.
Is there any way to contact the CHET team? I see they removed one of the stars from the sequence, but didn't add any more based on Bruce Gary's analysis of the field. With this star, it would be helpful to have more stars so I can use ensemble photometry (new to me!).
The sequence team is the CHET team. I added Bruce's stars numbered 8 and 12 from his list of stars (labels 133 and 124, respectively). I also added a 130 star but it is almost 11 arcmin away from the target. I don't know what your field of view is but in a 25 arcmin FOV you can also pick up 116 and 118 stars.
I looked at the field. Several of the stars Bruce uses are redder than the recommended limit of B-V >1.0 and 14th magnitude seems like a very dim comp tor the 11.9 V target. Several other candidates had conflicting stars. I didn't consider any stars fainter than 13.5 V mag.
At least you have a few more stars to use. If your field of view is greater than 18.5 arcmin try plotting an E chart to see if you can use some of the more distant comps as well as the previously existing "F" field stars and the 2 stars in Bruce's list that I added (but use the VSP sequence table photometry information).
Brad Walter, WBY
Thanks Brad, my previous chart size was not showing some of them and with the old chart id, not surprisingly the new stars did not appear, so I did not notice the new ones. As it turns out most of the new ones will fit on my FOV, all of them if I offset the centre.
--- Dave LDJ
AAVSO Alert Notice 672 requests timeseries of KIC 8462852 in support of monitoring underway by TESS. Please see the notice for details and observing instructions.
Many thanks, and Good observing,
Elizabeth O. Waagen, AAVSO HQ
There are 22 more Kepler stars in My FOV that AAVSO does not recognize. All have good SNR. Same for other Kepler fields. Can all the Kepler stars be added to the AAVSO database?
Interesting discussion, but I'm confused by two thinks:
a) Just to be sure, by "Kepler stars", you mean a star that was flagged to be variable or potentially variable in the Kepler field, right? (Just being in the KIC Kepler Input Catalog would not justify giving it a space in the AAVSO database IMHO)
b) If it's a suspected or demontrated variable star, it should be in VSX and hence would have an id that would allow submission to AAVSO's measurements database.... so if it's not in VSX, anyone here is free to submit it to VSX, right?? AAVSO is all about crowd sourcing, so that would be the normal workflow?
a) I did not know. Just because it has an assigned KIC or KID number does not necessarily mean its variable. So Ive learned something new today. So unless it has an assigned AUID already than it can not be submitted until the VSX process can be completed.
Good info, Thanks
I agree with Ray. I have at least 3 years of data on this field alone 24 X 24 arcmin. Seems such a waste not to be able to submit data for all the Kepler stars. I don't mind reducing the images and submitting them if they can be put to use. Just imagine what all of us could contribute from all the years of data going unused!
It's my understanding that if it is on the chart from VSP, it is in the VSX data base. However, it may not have a AUID if no one has ever asked for one. You can request an AUID (log in to the VSX page) but consider that many of these "variables" are low millimag variables and not really suitable for observation.
Right, thats what I understand now. I pulled this frame up in VPHOT after uploading some images of KIC 8462852. Of all of these stars marked only 2 others turned out to have AUID numbers already assigned. VPHOT checked these automatically for me so it was an easy task.
So to make a long story short, this can be done with any of our images to maximize the data from each image we submit to the database. It is worth checking no matter what the target star is to see if other stars in the same field can be measured and sent in as well. And if you find you need an AUID number for a new one you can go through the VSX process to aquire it along with a sequence for the new star.
Some of you may already be doing this so it is probably "Old Hat" to you. as for myself Ive just created alot of new work that should be alt of fun. Good cloudy weather or winter projects Im sure.
Glad to see the discussion. I have learned a couple things as a result.
AAVSO has a lot of good teachers.
I submitted one from another Kepler field to VSP just to see what would happen.
Sebastian responded the next day with some wisdom:
The Kepler data showed that that particular star varied about 0.001 mag. There is little chance that a ground based small telescope can see that. Not to say that that the star won't explode someday. But even if it does, Kepler will have a prior record of it.
Meanwhile, my skies and equipment can detect, at best, a delta of 20 to 30 mmag on a good night. At 243 meters ASL, I have a lot of gas between me and space. I use an 8" F6.3 and average 500 to 2100 seconds to get 50 mmag at 13 mag. (I quote those numbers from memory, rather than careful analysis of my data.) Skies are never "photometric" here. I can easily see KIC 9772007 change from 15.2 mag to 14.2 mag, but the scatter at mag 15.3 was 200 mmag for a recent run of 700 seconds averaging.
So while Tabby has a bunch of KIC and KIDs in the FOV, I plan to use the arXiv literature, VSX and my own data to see if any of them are useful targets for my equipment and skill level. If one is found with known > 50 mmag variability, I would submit it for an AUID. In deference to members with planet-finding equipment, we could maybe make that 20 mmag.
After some study, I do have a KIC that I think would be observable, so I may ask for an AUID for that one. Need to do some more quality control checking though.
Amateurs aren't the only observers still learning about Kepler stars. If you read the story of KIC 9832227, you will find that the professionals buggered a prediction of detectable gravity waves when they got their time base confused by hours. Since I know folks with 4 km IFO's and I personally take data on 40 meter IFO's, I took a ton of data on that star, and wondered why the period was not shortening. Silly me.
We may have a dimming event underway, first spotted a couple days by citizen scientist Gary Sacco and just confirmed by Bruce Gary. Data show that B band is down ~2%. If you have time in your schedules, we would be super grateful to have you collect some data for us!