The first photometric light curve investigation of the NSVS 8294044,V1023 Her,and V1397 Her binary systems is presented.We used ground-based observations for the NSVS 8294044 system and Transiting Exoplanet Survey Sat...The first photometric light curve investigation of the NSVS 8294044,V1023 Her,and V1397 Her binary systems is presented.We used ground-based observations for the NSVS 8294044 system and Transiting Exoplanet Survey Satellite data for V1023 Her and V1397 Her.The primary and secondary times of minima were extracted from al the data,and,by collecting the literature,a new ephemeris was computed for each system.Linear fits for the O-C diagrams were conducted using the Markov Chain Monte Carlo (MCMC) method.Light curve solutions were performed using the PHysics Of Eclipsing BinariEs Python code and the MCMC approach.The systems were found to be contact binary stars based on the fillout factor and mass ratio.V1023 Her showed the O’Connell effect and a cold starspot on the secondary component was required for the light curve solution.The absolute parameters of the system were estimated based on an empirical relationship between orbital period and mass.We presented a new T–M equation based on a sample of 428 contact binary systems and found that our three target systems were in good agreement with the fit.The positions of the systems were also depicted on the M–L,M–R,q–L_(ratio),and M_(tot)–J_(0)diagrams in the logarithmic scales.展开更多
Low mass ratio contact binary systems are more likely to have unstable orbits and potentially merge.In addition,such systems exhibit characteristics such as starspots and high energy emissions(UV)suggestive of chromos...Low mass ratio contact binary systems are more likely to have unstable orbits and potentially merge.In addition,such systems exhibit characteristics such as starspots and high energy emissions(UV)suggestive of chromospheric and magnetic activity.Light curve modeling of ten contact binary systems is reported.All were found to be of extreme low mass ratio ranging from 0.122 to 0.24 and three were found to be potentially unstable and possible merger candidates.Filling of the infrared calcium absorption lines is a marker of increased chromospheric activity.We use the available Large Sky Area Multi-Object Fiber Spectroscopic Telescope spectra along with matched standard spectra(broadened for rotation)to measure the excess filling of the central core depression flux of the two main infrared calcium absorption linesλ8542 andλ8662.We find that all reported contact binaries have excess filling of the core flux in the infrared calcium lines.Three of the systems reported were also observed by the Galaxy Evolution Explorer mission and we find that all three have features of excess ultraviolet emissions further adding evidence for increased chromospheric activity in low mass ratio contact binaries.Analysis of both orbital stability and absorption line filling is dependent on the determination of geometric and absolute parameters from light curve modeling.Not an insignificant number of contact binary light curves exhibit the O’Connell effect,usually attributed to starspots.We discuss the inclusion of starspots in light curve solutions and how they influence the geometric and absolute parameters.展开更多
We present photometric analysis of three bright red nova progenitor contact binary systems:ASAS J082151-0612.6,TYC 7281-269-1 and TYC 7275-1968-1.The primary components in all three systems are solar-type low mass sta...We present photometric analysis of three bright red nova progenitor contact binary systems:ASAS J082151-0612.6,TYC 7281-269-1 and TYC 7275-1968-1.The primary components in all three systems are solar-type low mass stars with radii somewhat larger than their zero age main sequence counterparts.The secondaries,as in most contact binary systems,have radii and luminosities well above their main sequence counterparts.All three have extremely low mass ratios ranging from 0.075 to 0.097 and two have high degrees of contact,in excess of 75%.All three have mass ratios and separations below the theoretical values for orbital stability.Chromospheric activity,a hallmark of magnetic activity and magnetic braking,considered important in mediating angular momentum loss,is also explored.All three systems demonstrate the O’Connell effect,and all systems require the introduction of star spots for a better light curve solution.In addition,we show that ASAS J082151-0612.6 and TYC 7281-269-1 have a UV color excess in the range indicating high chromospheric activity.Another measure of potential significant magnetic activity is X-ray luminosity;TYC 7275-1968-1 and probably also TYC 7281-269-1 have X-ray luminosity well above other contact binary systems.We conclude that it is likely that all three are unstable and hence are potential merger candidates.展开更多
The first multiband photometric solutions of the short-period V Gru eclipsing binary from the southern hemisphere are presented in this study.Light curves of the system were observed through BVI filters at the Congari...The first multiband photometric solutions of the short-period V Gru eclipsing binary from the southern hemisphere are presented in this study.Light curves of the system were observed through BVI filters at the Congarinni Observatory in Australia for 15 nights.In addition to the new ground-based data,we also used the TESS observations in two sectors.We analyzed the light curves of the system using the PHysics Of Eclipsing BinariEs(PHOEBE)2.4.7 version code to achieve the best accordance with the photometric observations.The solutions suggest that V Gru is a near-contact binary system with q=1.302(81)mass ratio,f_(1)=0.010(23),f_(2)=-0.0.009(21),and i=73.45(38).We considered the two hot spots on the hotter and cooler components for the light curve analysis.We extracted the minima times from the light curves based on the Markov Chain Monte Carlo(MCMC)approach.Using our new light curves,TESS,and additional literature minima,we computed the ephemeris of V Gru.The system’s eclipse timing variation trend was determined using the MCMC method.This system is a good and challenging case for future studies.展开更多
文摘The first photometric light curve investigation of the NSVS 8294044,V1023 Her,and V1397 Her binary systems is presented.We used ground-based observations for the NSVS 8294044 system and Transiting Exoplanet Survey Satellite data for V1023 Her and V1397 Her.The primary and secondary times of minima were extracted from al the data,and,by collecting the literature,a new ephemeris was computed for each system.Linear fits for the O-C diagrams were conducted using the Markov Chain Monte Carlo (MCMC) method.Light curve solutions were performed using the PHysics Of Eclipsing BinariEs Python code and the MCMC approach.The systems were found to be contact binary stars based on the fillout factor and mass ratio.V1023 Her showed the O’Connell effect and a cold starspot on the secondary component was required for the light curve solution.The absolute parameters of the system were estimated based on an empirical relationship between orbital period and mass.We presented a new T–M equation based on a sample of 428 contact binary systems and found that our three target systems were in good agreement with the fit.The positions of the systems were also depicted on the M–L,M–R,q–L_(ratio),and M_(tot)–J_(0)diagrams in the logarithmic scales.
基金support by the Astronomical station Vidojevica,funding from the Ministry of Science,Technological Development and Innovation of the Republic of Serbia(contract No.451-03-66/2024-03/200002)by the EC through project BELISSIMA(call FP7-REGPOT-2010-5,No.265772)financed by Silesian University of Technology Statutory Activities grant No.BK-250/RAu-11/2024。
文摘Low mass ratio contact binary systems are more likely to have unstable orbits and potentially merge.In addition,such systems exhibit characteristics such as starspots and high energy emissions(UV)suggestive of chromospheric and magnetic activity.Light curve modeling of ten contact binary systems is reported.All were found to be of extreme low mass ratio ranging from 0.122 to 0.24 and three were found to be potentially unstable and possible merger candidates.Filling of the infrared calcium absorption lines is a marker of increased chromospheric activity.We use the available Large Sky Area Multi-Object Fiber Spectroscopic Telescope spectra along with matched standard spectra(broadened for rotation)to measure the excess filling of the central core depression flux of the two main infrared calcium absorption linesλ8542 andλ8662.We find that all reported contact binaries have excess filling of the core flux in the infrared calcium lines.Three of the systems reported were also observed by the Galaxy Evolution Explorer mission and we find that all three have features of excess ultraviolet emissions further adding evidence for increased chromospheric activity in low mass ratio contact binaries.Analysis of both orbital stability and absorption line filling is dependent on the determination of geometric and absolute parameters from light curve modeling.Not an insignificant number of contact binary light curves exhibit the O’Connell effect,usually attributed to starspots.We discuss the inclusion of starspots in light curve solutions and how they influence the geometric and absolute parameters.
基金financial support of the Ministry of Education,Science and Technological Development of the Republic of Serbia through contract No.451-03-68/2022-14/200104financial support of the Ministry of Education,Science and Technological Development of the Republic of Serbia through contract No.451-03-9/2021-14/200002。
文摘We present photometric analysis of three bright red nova progenitor contact binary systems:ASAS J082151-0612.6,TYC 7281-269-1 and TYC 7275-1968-1.The primary components in all three systems are solar-type low mass stars with radii somewhat larger than their zero age main sequence counterparts.The secondaries,as in most contact binary systems,have radii and luminosities well above their main sequence counterparts.All three have extremely low mass ratios ranging from 0.075 to 0.097 and two have high degrees of contact,in excess of 75%.All three have mass ratios and separations below the theoretical values for orbital stability.Chromospheric activity,a hallmark of magnetic activity and magnetic braking,considered important in mediating angular momentum loss,is also explored.All three systems demonstrate the O’Connell effect,and all systems require the introduction of star spots for a better light curve solution.In addition,we show that ASAS J082151-0612.6 and TYC 7281-269-1 have a UV color excess in the range indicating high chromospheric activity.Another measure of potential significant magnetic activity is X-ray luminosity;TYC 7275-1968-1 and probably also TYC 7281-269-1 have X-ray luminosity well above other contact binary systems.We conclude that it is likely that all three are unstable and hence are potential merger candidates.
基金The National Science Foundation(NSF 1517474,1909109)the National Aeronautics and Space Administration(NASA 17ADAP17-68)both contributed funding to PHOEBE that we utilized。
文摘The first multiband photometric solutions of the short-period V Gru eclipsing binary from the southern hemisphere are presented in this study.Light curves of the system were observed through BVI filters at the Congarinni Observatory in Australia for 15 nights.In addition to the new ground-based data,we also used the TESS observations in two sectors.We analyzed the light curves of the system using the PHysics Of Eclipsing BinariEs(PHOEBE)2.4.7 version code to achieve the best accordance with the photometric observations.The solutions suggest that V Gru is a near-contact binary system with q=1.302(81)mass ratio,f_(1)=0.010(23),f_(2)=-0.0.009(21),and i=73.45(38).We considered the two hot spots on the hotter and cooler components for the light curve analysis.We extracted the minima times from the light curves based on the Markov Chain Monte Carlo(MCMC)approach.Using our new light curves,TESS,and additional literature minima,we computed the ephemeris of V Gru.The system’s eclipse timing variation trend was determined using the MCMC method.This system is a good and challenging case for future studies.
