J2254

SRGA J225412.8+690658

Observations

We used iTelescope Network of Telescopes to observe J2254 from Deep sky Utah on 6/8/2023. The data we gathered gave us a belief that what we were looking at was an IP, yet the X-rays brightness does show that the relationship is magnetic. We collected a total of 96 images. All the images had an exposure time of 300sec and bin 2. These images were taken on four different nights. On 6/8/2023 we took 15 images. On 6/23/2023 and 6/26/2023 we took 24 images, and lastly on 6/27/2023 we took 33 images.

In early 2024 I did a reanalysis of this source using AstroPy and found a less convincing story for the period. Both sets of analyses are presented here, original first.

Creating Comparison Stars

After seeing AAVSO chart, the two comparison stars given were oversaturated in all of the images due to the high exposure time. After an unsuccessful search to find comparisons using Simbad, to solve this issue, we took images with lower exposure time. The CV was not visible, yet the comparison stars were not oversaturated. We used those two comparisons stars with 4 target stars. Then we took the average of each target's magnitude, which gave 4 new comparison stars that weren't oversaturated in the 300sec exposure.

Combined Images (CLEANest)

After combining all are images into one observation set and subtracting the brightness difference, we created a period analysis and a phase plot with the most significant period. The top period is 2.6 hours long.

Using Peranso, we calculated the FAP of the top period and got a percentage around 8.9%.

Combined 3 Days (Lomb-Scargle GLS)

We used all images besides the 33 that were taken on 6/8/2023

Without the last images the period drops to 1.6 hours.

However, when running the significance analysis the FAP is raised to 68%.

Raw Data for these observations

2024 Reanalysis

In early 2024 I did a reanalysis of both the photometry and the periodogram for this source, and found that the story is even less clear than we originally thought. I think I was a little more careful with the photometry, but it doesn't seem to make a difference. This was done with AstroPy and the Lomb-Scargle package.

In the periodigrams for each individual day (below), there is some evidence for low-frequency behavior (around 20 1/d) - but it is not at all present in the 0626 observation. It remains present in the combined periodogram, but the phase plot is not convincing, to say the least. That feature was interesting enough to me that I did try removing the 0626 observation and check out the folded phase, but still nothing. You could essentially move the phase of the model around however you like and find a reasonable fit to the data.

I think this source will remain a mystery, but it might be interesting to design an observation program around specifically looking for that 100 min period. Although classified as a CV (https://arxiv.org/pdf/2107.05611.pdf), and listed as "possibly magnetic" (https://asd.gsfc.nasa.gov/Koji.Mukai/iphome/systems/srga225412.html), we do not see convincing sign of a periodic signal.

Phase folded on 100.4 min.

Report abuse