Researcher: Melanie Isenbarger

Observations suggest that NSVS 6103255 is an eclipsing variable star of W Ursae Majoris type. This star is located at α=22:29:35.20 δ=+37:57:31.44 and has the following alternate stellar designations: HD 213271, GSC 0200-01872, Gaia DR2 1907779946960802944, Gaia DR1 1907779942662517120, 2MASS J22293519+3757313, TYC 3200-1872-1.  Star field with the target star and comparison stars used in ensemble differential photometry are shown in Figure 1.
We have observed this star with the Ball State University Observatory (BSUO) 20-inch (0.5m) telescope in the Johnson B (B) & V (V), and Cousins R (Rc) bandpasses. All stellar photometry is performed by the AstroImageJ (AIJ) software package. All photometry is performed with similar ensemble stars. If a calibrated magnitude for a comparison star is known, then it is used by AIJ to calibrate the magnitude for the target star. Folded light curves for Johnson V and (B-V) color are shown in Figure 2.

Figure 1: Star field with ensemble stars used for differential photometry marked. The eclipsing variable star NSVS 896797 is marked by the green target (T1). All ensemble stars are marked by the red apertures and designated the labels C2-C13. If a B band magnitude is known, it is given with each comparison, in Table 1. Field-scale is given on the bottom left corner of the image.
(J2000.0) Magnitudes
Comparison Catalog α δ B V Rc
C2 TYC 4558-825-1 13:27:40.48 +75:40:40.50 12.32 ± 0.17 11.61 ± 0.11 —
C3 TYC 4558-2171-1 13:26:17.48 +75:40:05.66 12.80 ± 0.24 11.74 ± 0.12 —
C4 — 13:27:10.17 +75:40:35.83 — — —
C5 — 13:27:22.63 +75:40:41.13 — — —
C6 — 13:28:07.94 +75:40:44.06 — — —
C7 — 13:26:36.13 +75:42:22.25 — — —
C8 — 13:28:04.09 +75:43:29.66 — — —
C9 — 13:28:34.38 +75:42:38.81 — — —
C10 TYC 4558-255-1 13:27:26.00 +75:44:00.77 11.69 ± 0.07 11.14 ± 0.07 —
C11 TYC 4558-825-1 13:27:40.48 +75:40:40.50 12.32 ± 0.17 11.61 ± 0.11 —
C12 TYC 4558-825-1 13:27:40.48 +75:40:40.50 12.32 ± 0.17 11.61 ± 0.11 —
C13 TYC 4558-825-1 13:27:40.48 +75:40:40.50 12.32 ± 0.17 11.61 ± 0.11 —

Best fitting Wilson-Devinney (WD) Models
All modeling is performed using the PHysics Of Eclipsing BinariEs (PHOEBE) (v0.31a) software package. PHOEBE is a graphical user interface (gui) to the WD code that is used to model binary stars. Figure 3 shows the best fit WD model with two star spots included. Figure 4 shows a graphical representation of the stellar surface.

Derived System Parameters
Below is a Table 3, which lists parameters and their values derived in the analysis of this system via the methods discussed above.

No Spots Spots
Parameter Symbol [unit] Value Error Value Error
(1) (2) (3) (4) (5) (6)
Period P [days] 0.939
Epoch T0 [HJD]
Inclination i [deg]
Surface Temp. Teff,1 [K] 6800
Teff,2 [K]
Surface Potential Ω1,2 [-]
Mass Ratio q [-]
Stellar Mass‡ M1 [M☉] 1.4
M2 [M☉]
Semi-major Axis‡ a [R☉]

Table 3: System parameters of NSVS 6103255.  Column (1) gives the name of the parameter, (2) gives the parameter symbol and [units], (3) and (4) give the parameter value and error, respectively, without spots (no spots), while (5) and (6) give the parameter value and error with spots (spots). Any blanks in the table denote data which is, as of the last edit, unknown and/or unavailable. Please note that these parameters may change as the modeling of the system progresses.
‡These values were calculated using the the equations in Harmanec (1988). These equations assume our star(s) are main sequence, which is suspect. We only include the values as crude estimates, as spectral and radial velocity data will be required to obtain more certain values.

Presentations
Poster presentations and talks given by Melanie Isenbarger at national, regional and local conferences for NSVS 6103255 are given below.

  1. NSVS 6103255. Ball State University Physics & Astronomy colloquium, December 5, 2019.

Contact Information
All members of the Variable Star Research group are enthusiastic researchers with a passion for the work performed by the group. We are always happy to discuss any research projects and are always looking for like-minded and enthusiastic collaborators. For more information regarding any of the aforementioned research activities or the research activities of the Variable Star Research Group, please do not hesitate to contact Robert Berrington.