Peremennye Zvezdy

"Peremennye Zvezdy",
Prilozhenie
,
vol. 12, N 7 (2012)

GSC 6558-01290, a New Double-Mode RR Lyrae Variable Star

A. V. Khruslov
Institute of Astronomy, Russian Academy of Sciences, Moscow, Russia

Received:   24.05.2012;   accepted:   31.07.2012
(E-mail for contact: khruslov@bk.ru)


Star Name: GSC 6558-01290, ASAS 075842-2536.1
Coordinates (J2000): 07 58 42.16, -25 36 00.9
Variability type: RR(B);   Limits, System: 11.8 – 12.3 (V);    
Period: (see Remarks) d;   Epoch(max): JD (see Remarks)

Remarks:
The variability of GSC 6558-01290 = ASAS 075842-2536.1 was discovered by Pojmanski (2002). The ASAS-3 catalog lists the variable as an RRC star with the period of 0.41013 d.

I reinvestigated the star using the currently available ASAS-3 data and found it an RR(B) star, pulsating in the first and second overtone modes (an extension of the GCVS RR(B) type, which is defined as fundamental-mode and first-overtone pulsators). The phased light curves plotted for the tabulated elements are shown in the Figure.





ModeFrequency, c/d Semi-amplitude, V mag Period, day Epoch, HJD
f1 2.43827 0.158 0.410127 2453600.253
f2 3.04768 0.033 0.328118 2453600.318


The period ratio P2/P1 = 0.8000 is typical of double-mode variables pulsating in the first and second overtone modes. The tabulated coordinates of the variable were drawn from the Tycho2 catalog. J–H = 0.231 (2MASS). The star is in a close pair with the much fainter GSC 6558-00870; the combined brightness was measured, thus the actual amplitude can be somewhat larger.

References:
Pojmanski, G., 2002, Acta Astron., 52, 397

Light Curve
GSC 6558-01290, a New Double-Mode RR Lyrae Variable Star


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