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Potential DSCT

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GDonnelly
Potential DSCT

Hello everyone, 

I have prepared a variable star for submission to VSX, and based on the recent changes to procedure due to the increasing amount of submissions, I'm posting here with the details on this object to obtain feedback before a submission to VSX. I first identified this object from ROTSE1:Orphans data. It has a period of 0.160799 days, an amplitude of 0.059, a maximum magnitude of 12.08, and a minimum magnitude of 12.14. Based on the data I believe that this object is a DSCT.

I have attached a phased plot using data from ROTSE1:Orphans, ROTSE1:NSVS, and ASAS-SN. 

Any feedback would be very appreciated!

 

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Sebastian Otero
Sebastian Otero's picture
Some comments

ASAS-SN data have become available over the past year.
The scatter will be much lower than the ASAS-3 scatter (when you mention "ASAS" you need to specify "ASAS-3" or "ASAS-SN"). And ASAS-SN is all sky.

The phase plot whould show an epoch of maximum (the one given in the VSX table) as phase 0.

The amplitude is given as 0.60 in the plot when it is 0.06. A typo? Scatter should always be taken into account to determine amplitudes or ranges.

Cheers,
Sebastian

GDonnelly
Thank you for the response!

Mr. Otero, 

Thank you for your helpful response. The discrepancy between 0.6 and 0.06 was indeed a typo, thanks for pointing that out. However, I have since recalculated the amplitude including data from ASAS3. The new amplitude is 0.057. To clearify, ASAS data is ASAS3. I have updated the original post to include all of this information, and I made a new plot as well. 

When you mention the epoch of maximum at phase 0, I have that information. This epoch is HJD 2451792.719. Is this what you meant? 

Thank you,

Grant

 

GDonnelly
Amplitude Discussion

Mr. Otero,

I gave further thought toward the amplitude of this object. I attached a plot of the ASAS3 data for this object with the period forced to the period derived from the ROTSE1 data. From the plot, the scatter of the ASAS3 data for this object is around 2.5 times the amplitude from the ROTSE1 data or the supposed ASAS3 data. This calls into question the validity of any amplitude relying on the ASAS3 data for this object. This combined ROTSE1+ASAS3 amplitude would therefore not be indicative of the true amplitude. I would prefer to use the amplitude from the ROTSE1 data (0.060) as it is more defensible.

Let me know what you think.

Grant

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GDonnelly
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Sebastian Otero
Sebastian Otero's picture
ASAS-SN not ASAS-3

Grant, you keep using ASAS-3 when I suggsted using ASAS-SN which has a much better quality at mag. 12.
I read a post that I can't find now where you mentioned that you weren't going to use ASAS-SN data because therer were just a few datapoints. That was surely due to the fact that the search form only goes 20 days backwards when trying to retrieve data. You have to enter something like 2500 in the "Enter number of days to go back" field to get all the available observations.

Also, do not give amplitudes to three decimal places since that is not justified by the precision of the data.

About epochs, an epoch of maximum is what you need to determine for pulsating variables and the phase plot should show the determined epoch as phase 0.

Cheers,
Sebastian

GDonnelly
ASAS-SN Data

Mr. Otero,

Thanks for getting back to me. I did post a reply about the ASAS-SN data earlier, but right after I realized my mistake about the data going back just 20 days, and I got rid of the post while I worked with the ASAS-SN data. This data turned out really well, if you look at the plot attatched in the original post, it now includes ASAS-SN, and no longer has ASAS3. I'm now using V band for this object, since I can work well with ASAS-SN now. I can now say with confidence that the amplitude is 0.059, as that is calculated from all three data sources now.

There is one other problem, however. I have measured the rise % for this object a few different ways now, and each time I get something close to 52%. This is evident on the plot in the original post, with minimum magnitude at phase 0 and maximum amplitude at phase 0.52416. As this is too high for a DSCT, should this rise % be reported in the submission form? 

Grant

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