Dip of lightcurve on a non variable star

Hello Ivaldo,

If I had found this, I would continue to observe it!  0.6 magnitudes deep, 2 hour duration.  I think that's just a little bit shorter duration than I'm using to seeing for short duration eclipses of this depth, but I think it is quite possible for an eclipsing system.   I you haven't already done so, check to see if any wide-area or all-sky surveys have caught this star in a dim state.

Good luck!

Gary Billings

Thank you for your reply, Gary. I'll follow your advice.

Hey Ivaldo,

Gary is right that looks like a clear (and very deep eclipse). Considering the size of the eclipse I find it very likely that there will be a second eclipse as well. I'm not sure how well versed you are on other data archives, but If you have the coordinates, the easiest place to go and explore the lc quickly is :

https://asas-sn.osu.edu

I would first try a fairly narrow day range (the default of 20 might be okay) as it does photometric reduction on the spot so it can take a while if you do 2000+ days which is it's observation range. If you did want to find a period though I would download the full data range and do a period search which can be done fairly easily in Vstar (since the asassn sampling probably won't make it obvious). If you have any more questions let us know.

Thanks,

Bert Pablo
Staff Astronomer, AAVSO

The plot coantining AAVSO data (fig 1) and the LCG don't match. LCG is missing some of the published data. And LCG2 truncates, leaving the user to wonder what happened before and after.

I managed for three consecutive nights to resume the primary minimum of this probable variable star EA. This allowed me to calculate roughly the period that I find to be about 0.9368 days. I continued the observations for a few days but I could not complete a cycle and I could not find out if there is a secondary minimum. Since here the weather is bad in Switzerland, I was wondering if some amateur astronomer in the world would like to use his telescope to help me with my observations. The star has a V magnitude of about 14.3 and R of about 13.7. With a telescope of only 150 mm in diameter, I shot it with the CCD using 5 minute long shots. I do not know how to do in these cases. I would be sorry to lose the paternity of the discovery by publicly revealing the position of the star, for the moment.

Hi Ivaldo,
it is only in a limited number of cases or when stars are too faint or too bright for ASAS-SN when there will actually be a need of additional observations.
You can download ASAS-SN data by following the VSX external link after a positional search.
Remember to write 2600 or a similar figure in the "Enter number of days to go back" field to get all the observations and not just the default last 20 days of data.

Cheers,
Sebastian

I thank all of you for the help you are giving me. At the moment my problem is that I can not correctly put the ASAS-SN data in phase with those obtained from my shots. My best result is a period of 0.8892096 (see image 01), but the curves do not match. If, however, I ignore the data of ASAS-SN my best estimate of the period is 0.933884 (see image 02) and there seems to exist a secondary minimum. If you want to try I have also attached the CSV file of the observations downloaded by ASAS-SN for this star.

Hi Ivaldo.

I got a period of 0.94016 for the ASAS-SN data. Does that period fit your observations? In the ASAS-SN data there are some divergent (faulty) points I think you can remove to get a better lightcurve. With this period you got a primary and secondary dip of about equal depth.

Ivaldo

can you give the RA and Dec of your target? will be glad to take a look, if visible

Mike MIller-  Georgetown,TX