An Analysis of the Symbiotic Star Z And Line Profile

Lee, Seongjae; Hyung, Siek; Lee, Kangwhan

doi:10.5467/jkess.2012.33.7.608

Cited by 4 publications

(3 citation statements)

References 7 publications

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“…The FWHM broadening of line, i.e., 3~5 times faster than the expected gas movement, was known to be caused by Raman scattering mechanism in a place close to a high density neutral gas of column densitỹ 10 19 cm −2 near the HII zone (Lee and Hyung, 2000;Lee et al, 2012). The broader line profile component obviously does not indicate a swiftly flowing gas activity.…”

Section: H and He Linesmentioning

confidence: 97%

Spectroscopic Study of the Symbiotic Star CI Cyg

Hyung¹

2014

Journal of the Korean earth science society

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We secured the high dispersion spectra of the symbiotic star CI Cyg. The HI, HeI, and HeII line profiles were analyzed using the relatively long exposure data including 1800 sec (Sep. 12, 1998, phase=0.90), 3600 sec (Aug. 12, 2002, and 1800 sec (Oct. 21, 2009, φ =0.54). Although a minor outburst was reported in 2008, our three observation periods were generally known to be quiescent in earlier photometric studies. With the help of hydrodynamic simulations, we identified the two emission zones responsible for the blue-and red-shifted line components: (a) an accretion disk around a hot white dwarf star which consists of the outer cool HeI emission zone and the inner hot HeII emission part, and (b) a high density zone near the inner Lagrangian point responsible for the HeI line flux variation and the broadening of its line profile. The HeII line fluxes indicate that the HeII emission zone of the accretion disk is relatively stable, implying a constant gas inflow from the giant star throughout the quiescent period. The 2002 HeI data showed that the notable mass flow activity through the inner Lagrangian point occurred during this period and its flux intensity became strongest, whereas the HeII line width in the same period indicates that its flow activity forced the accretion disk to expand. The [OIII] lines were observed in 1998 but not detected in 2002 and 2009, implying the disappearance of the low density zone. Based on our kinematical studies upon the line profiles, we conclude that CI Cyg was stable in 1998 among the three observation periods selected in this research.

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Section: H and He Linesmentioning

confidence: 97%

Spectroscopic Study of the Symbiotic Star CI Cyg

Hyung¹

2014

Journal of the Korean earth science society

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“…where, JD obs indicates the observation date in Julian date format. According to the ephemeris, when the GS eclipses the WD (the minimum brightness), the phase is defined as 0 (Φ = 0) (Lee et al 2012). However, we have utilized JD Max(V) = JD 2,442,710.0 + 816.5•E suggested by Iben & Tutukov (1996), in reference to the maximum brightness, to calculate the orbital phase of AG Peg.…”

Section: Bservation and Data Reductionmentioning

confidence: 99%

N III Bowen Lines and Fluorescence Mechanism in the Symbiotic Star AG Peg

Hyung,

Lee,

Lee

2018

Journal of Astronomy and Space Sciences

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We have investigated the intensities and full width at half maximum (FWHM) of the high dispersion spectroscopic N III emission lines of AG Peg, observed with the Hamilton Echelle Spectrograph (HES) in three different epochs at Mt. Hamilton’s Lick Observatory. The earlier theoretical Bowen line study assumed the continuum fluorescence effect, presenting a large discrepancy with the present data. Hence, we analyzed the observed N III lines assuming line fluorescence as the only suitable source: (1) The O III and N III resonance line profiles near λ 374 were decomposed, using the Gaussian function, and the contributions from various O III line components were determined. (2) Based on the theoretical resonant N III intensities, the expected N III Bowen intensities were obtained to fit the observed values. Our study shows that the incoming line photon number ratio must be considered to balance at each N III Bowen line level in the ultraviolet radiation according to the observed lines in the optical zone. We also found that the average FWHM of the N III Bowen lines was about 5 km·s-1 greater than that of the O III Bowen lines, perhaps due to the inherently different kinematic characteristics of their emission zones.

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“…The expansion velocity study results have been a base for a further detailed investigation, such as distance determination, nebular shaping simulation, and kinematics studies. Unlike symbiotic stars (see e.g., Lee et al, 2012;Hyung, 2014), PNe (Lee and Hyung, 2007) show numerous forbidden lines that are useful for a velocity field study. In this investigation, we will newly derive the expansion velocity of the main shell from all the available forbidden lines secured at the center of NGC 7027 image with Bohyunsan Optical Echelle Spectrograph (BOES), hoping that the results will become a basis for a future shaping study.…”

Section: Introductionmentioning

confidence: 99%