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Short double period variable

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Short double period variable

Hi everyone,

I found a new variable through data mining. It is a short double period variable. Data consists of two blended stars, while the fainter one is almost 3 mag fainter, 8" away (see ASAS-SN link below). I've also proven that the brighter star is variable.

Two periods have been found, also SWASP data show a clear GDOR-ish shape: 0.05751797 d and 0.05943872 d. They both look rather sinusoidal. J-K= 0.14, B-V= 0.27.

Here's the ASAS-SN link for both stars, so you won't have to spend time on waiting for data again:

My first suggestion was a SXPHE(B) variable, because all GDOR variables on VSX have much longer period. Sometimes there are, but those are GDOR+DSCT with three or more periods (here I have 2). But there aren't many SXPHE(B)s on VSX (only 8), also they all have amplitude larger (0.2-0.7 mag) than this one (~0.05 mag). What's more, the ratio is much smaller than there (mostly ~0.8 on SXPHE(B)'s, here we have almost 0.97. And, isn't the star too blue? The other solution might be BCEP, however on vartypes.txt list, it suggests period to be at least 0.1 day. There's also a BCEPS type, but we have 0.015-0.04 days there. My star is between those.

Small amplitude made me think that the fainter companion might be variable. To find a solution, I have attempted to submit a tricky position, where only one of stars would be inside aperture. Here are two links of ASAS-SN submissions, which are in different positions (just by ~2"), showing a little larger scatter, but with smaller brightness (because companion was not included). That should be enough to see, that the bright (11 mag) star is actually variable.



What are your thoughts about it? Is it actually BCEPS?


Gabriel Murawski

AAVSO 49 Bay State Rd. Cambridge, MA 02138 617-354-0484