3 Spectral analysis

The normalized spectra of UX Ari are analyzed using the spectral subtraction technique described in detail by Barden (1985) and Montes et al. (1995). In this method, the synthesized spectrum is constructed from artificially rotationally broadened, radial-velocity shifted, and weighted spectra of two inactive stars with the same spectral-type and luminosity class as the two components of the active star. For our situation, the synthesized spectrum is constructed by means of the program STARMOD (Barden 1985); the two inactive stars HR 3309 (G5V) and HR 3351 (K0IV) observed in the same campaign are used as reference stars.

 

 

Table 2: The measurements for the excess emissions of the H$\alpha$ and Ca II IRT lines.

Phase	FWHM (Å)	EW (Å)	$I_{\rm c}$	$\log F_{\rm S}$ (erg cm-2 s-1)	EW8542/EW8498
	H$\alpha$, Ca II (8498,8542,8662)	H$\alpha$, Ca II (8498,8542,8662)	H$\alpha$, Ca II (8498,8542,8662)	H$\alpha$, Ca II (8498,8542,8662)
0.132	1.859 1.694 1.968 1.929	1.365 0.600 0.973 0.816	0.656 0.318 0.407 0.374	6.815 6.400 6.610 6.523	1.621
0.135	1.871 1.702 1.971 1.916	1.364 0.591 0.943 0.793	0.670 0.309 0.403 0.356	6.815 6.394 6.596 6.510	1.594
0.295	1.922 1.698 1.970 1.933	1.503 0.615 0.978 0.810	0.675 0.320 0.424 0.362	6.857 6.411 6.612 6.519	1.590
0.297	1.923 1.691 1.957 1.927	1.514 0.616 0.951 0.830	0.685 0.327 0.417 0.367	6.860 6.412 6.600 6.530	1.543
0.453	2.097 1.734 1.977 1.977	1.370 0.628 0.922 0.779	0.581 0.311 0.404 0.351	6.817 6.420 6.587 6.502	1.467
0.600	1.808 1.614 1.902 1.848	1.363 0.594 0.934 0.836	0.678 0.355 0.421 0.401	6.815 6.396 6.592 6.533	1.572
0.602	1.808 1.630 1.895 1.874	1.373 0.598 0.903 0.807	0.693 0.343 0.405 0.372	6.818 6.398 6.578 6.518	1.510
0.755	1.840 1.669 1.897 1.976	1.716 0.650 0.972 0.906	0.830 0.370 0.451 0.402	6.915 6.435 6.610 6.568	1.495
0.758	1.813 1.665 1.941 1.958	1.713 0.639 0.949 0.893	0.828 0.360 0.434 0.374	6.914 6.427 6.599 6.562	1.486
0.909	2.065 1.695 1.987 2.032	1.593 0.576 0.851 0.792	0.723 0.323 0.384 0.340	6.882 6.383 6.552 6.510	1.477
0.911	2.062 1.708 1.986 2.010	1.578 0.576 0.845 0.800	0.719 0.314 0.384 0.339	6.878 6.383 6.549 6.514	1.467
0.492	1.960 1.643 1.919 1.935	1.421 0.653 1.111 0.937	0.653 0.354 0.469 0.400	6.833 6.437 6.668 6.582	1.701
0.625	1.958 1.647 1.885 1.941	1.481 0.614 0.953 0.821	0.683 0.323 0.425 0.354	6.851 6.410 6.601 6.525	1.552
0.781	1.911 1.589 1.683 1.791	2.155 0.783 0.951 0.986	0.992 0.468 0.539 0.488	7.013 6.516 6.600 6.605	1.214
0.933	2.111 1.917 1.950 2.019	1.870 0.742 0.818 0.813	0.804 0.323 0.381 0.344	6.952 6.493 6.535 6.521	1.102

In the course of the analysis, the $v\sin{i}$ values (7.5/39 km s^-1) of the two components of UX Ari were taken from Duemmler & Aarum (2001), the intensity weight for each of the two components was obtained from two spectra taking at phases 0.295 and 0.297, where the two components are well separated. Finally, the adopted intensity weight ratios are 0.30/0.70 for He I D₃ and Na I D₁, D₂ line spectral region, 0.24/0.76 for H$\alpha$ line spectral region, 0.23/0.77 for Ca II IRT (8498.06 Å, 8542.14 Å) line spectral region, 0.21/0.79 for Ca II IRT (8662.17 Å) line spectral region.

The synthesized and subtracted spectra we have obtained in the different spectral regions are displayed in Figs. 2-7, where the orbital phases calculated using Duemmler & Aarum's (2001) new ephemeris are also marked. In these figures, "H'' and "C'' represent the primary (hotter component) and the secondary (cooler component), respectively. For the H$\alpha$ lines and Ca II IRT lines, offsets are added to the subtracted spectra for better display.

Figure 2: The profiles of the Na I D1, D2, and He I D3 lines in Feb. 2000. The dotted lines represent the synthesized spectra. The lower spectra are the subtracted spectra.

Figure 3: The profiles of the H$_\alpha$ lines in Feb. 2000. The dotted lines represent the synthesized spectra. The upper spectra are the subtracted spectra.

Figure 4: As Fig. 3, but for the Ca II IRT (8498, 8542) lines.

Figure 5: As Fig. 3, but for the Ca II IRT (8662) lines.

Figure 6: As Figs. 2 and 3, but for the observations in Sep. & Nov. 2000.

Figure 7: As Figs. 4 and 5, but for the observations in Sep. & Nov. 2000.