Orbital period changes and photometric study of contact binary system AK Her

Samadi, Azam; Jassur, D. M. Z.; Nassiri, S.; Gozaliasl, G.; Kermani, M. H.; Zareie, A.

doi:10.1016/j.newast.2009.09.007

Cited by 7 publications

(9 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Pribulla et al (2006) quoted f ( M ) = 1.598(29), while the correct value should be 1.502(29), which can be calculated from . From Samadi et al (2010), one can calculate the value of the mass function f ( M ) = ( M 1 + M 2 )sin 3 ( i ) = 2.300 M ⊙ . This value is quite different from the spectroscopic estimate 1.502(29).…”

Section: Results and Comparison With The Literaturementioning

confidence: 81%

“…These suggest that the system has a variable light curve and a variable period. Analysis of the updated O – C curves revealed evidence of continuously changing period with cycle length between 57 and 97 yr (Samadi et al 2010). Using the spectroscopic mass ratio of 0.26 from Sanford (1934), Samadi et al (2010) derived i (°) = 83.88 ± 0.27 and the parameters as listed in Table 9.…”

Section: Results and Comparison With The Literaturementioning

confidence: 99%

“…Analysis of the updated O – C curves revealed evidence of continuously changing period with cycle length between 57 and 97 yr (Samadi et al 2010). Using the spectroscopic mass ratio of 0.26 from Sanford (1934), Samadi et al (2010) derived i (°) = 83.88 ± 0.27 and the parameters as listed in Table 9. Using the spectroscopic radial velocity measurements, Pribulla et al (2006) obtained K 1 = 70.52 ± 1.12 km s −1 , K 2 = 254.40 ± 2.27 km s −1 .…”

Section: Results and Comparison With The Literaturementioning

confidence: 99%

“…The companion, located at a separation of 4.2 ′′ , is 3.5 mag fainter than AK Her at its maximum light (Pribulla et al 2006). The star has been the subject of numerous studies (Samadi et al 2010, and references therein). These suggest that the system has a variable light curve and a variable period.…”

Section: Asas 171358+16210 = Ak Hermentioning

confidence: 99%

“…This value is quite different from the spectroscopic estimate 1.502(29). Hence, the parameters determined by Samadi et al (2010) may not be reliable. We have analysed the ASAS light curve of AK Her using the spectroscopic mass ratio qsp = 0.277, considering A-type configuration and a spectral type F4V (Pribulla et al 2006).…”

Section: Asas 171358+16210 = Ak Hermentioning

confidence: 99%

See 4 more Smart Citations

Physical parameters of 62 eclipsing binary stars using the All Sky Automated Survey-3 data − I

Deb

Singh

2011

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We present a detailed light-curve analysis of publicly available V-band observations of 62 binary stars, mostly contact binaries, obtained by the All Sky Automated Survey (ASAS)-3 project between 2000 and 2009. Eclipsing binaries are important astronomical targets for determining the physical parameters of component stars from the geometry of their orbits. They provide an independent direct method of measuring the radii of stars. We improved the ASAS determined periods and ephemerides, and obtained the Fourier parameters from the phased light curves of these 62 stars. These Fourier parameters were used for preliminary classification of the stars in our sample. The phased light curves were then analysed with the aid of the Wilson-Devinney light-curve modelling technique in order to obtain various geometrical and physical parameters of these binaries. The spectroscopic mass ratios as determined from the radial velocity measurements available in the literature were used as one of the inputs to the light-curve modelling. Thus reliable estimations of parameters of these binaries were obtained with combined photometric and spectroscopic data, and error estimates were made using the heuristic scan method. For several systems in the sample, the solutions were obtained for the first time and would serve as a good source in the future for light-curve analysis based on more precise follow-up CCD photometric observations. Out of 62 stars in the sample, photometric analysis of 39 stars is presented here for the first time using the ASAS photometry and precise spectroscopic mass ratios. From the analysis, we found 54 contact binaries, six semidetached binaries and two detached binaries. The Fourier parameters in the a 2 -a 4 plane were used for preliminary classification, and the final classification was done based on the Roche lobe geometry obtained from the light-curve modelling.

show abstract

Section: Results and Comparison With The Literaturementioning

confidence: 81%

Section: Results and Comparison With The Literaturementioning

confidence: 99%

Section: Results and Comparison With The Literaturementioning

confidence: 99%

Section: Asas 171358+16210 = Ak Hermentioning

confidence: 99%

Section: Asas 171358+16210 = Ak Hermentioning

confidence: 99%

See 3 more Smart Citations

Physical parameters of 62 eclipsing binary stars using the All Sky Automated Survey-3 data − I

Deb

Singh

2011

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

A critical review of period analyses and implications for mass exchange in W UMa eclipsing binaries: Paper 4

Nelson¹,

Terrell

Milone

2023

New Astronomy Reviews

View full text Add to dashboard Cite

KIC 8975515: A fast-rotating (γ Dor – δ Sct) hybrid star with Rossby modes and a slower δ Sct companion in a long-period orbit

Samadi-Ghadim

Lampens

Jassur

et al. 2020

A&A

View full text Add to dashboard Cite

Aims. KIC 8975515 is a double-lined spectroscopic binary system with hybrid nature. Regular monitoring with the échelle spectrograph HERMES show that both components have matching atmospheric properties (Teff ∼ 7400 K), and that one of them is a fast rotator (v sin i = 162 versus 32 km s−1). Our aim is to study the Kepler light curve in order to determine the frequencies of the pulsations, to search for regular spacing patterns in the Fourier spectrum, if any, and to discuss their origin in the context of binarity and fast rotation. Methods. In this paper, we study the properties of the stellar pulsations based on a careful analysis of the Fourier spectrum. This was done by performing repeated frequency-search analyses with successive prewhitenings of all the significant frequencies detected in the spectrum. Moreover, we searched for regular period spacing among the g modes as well as frequency splitting among the g and p modes in frequency. Results. In the low-frequency regime, one series of prograde g modes and four series of retrograde r modes, were detected. The r modes are well-distributed with respect to the harmonics of the rotational frequency of the fast-rotating star frot = 1.647 d−1. The dominant g mode is f2 = 2.37 d−1. The strongest p mode is f1 = 13.97 d−1. We identified two multiplets of regularly split p modes with the mean values of 0.42 d−1 and 1.65 d−1. In addition, we also identified a few incidences of mode coupling (between f1 and a g or r mode). Conclusions. We detected five series of retrograde r and prograde g modes as well as two multiplets of p modes with rotational frequency splitttings related to both components of KIC 8975515. We identified the fast-rotating component as a hybrid pulsator with r modes, and the slowly-rotating component as a δ Sct pulsator.

show abstract

Orbital period changes and photometric study of contact binary system AK Her

Cited by 7 publications

References 10 publications

Physical parameters of 62 eclipsing binary stars using the All Sky Automated Survey-3 data − I

Physical parameters of 62 eclipsing binary stars using the All Sky Automated Survey-3 data − I

A critical review of period analyses and implications for mass exchange in W UMa eclipsing binaries: Paper 4

KIC 8975515: A fast-rotating (γ Dor – δ Sct) hybrid star with Rossby modes and a slower δ Sct companion in a long-period orbit

Contact Info

Product

Resources

About