Search For Black Hole Candidate Using Light-curve Minima Of Binaries And Radial Velocity From Lamost

The study of black holes has always been a hot topic in the field of astronomy.But the black hole cannot be observed directly,can only be searched and studied in an indirect way.Therefore,the search and study of black hole is a difficult subject in astrophysics.This paper is about two methods to search for black holes and consists of two main parts.First,the period changes of the five eclipsing binaries are studied with their minimum to search for black hole candidates.At the same time,the orbital parameters of the five eclipsing binaries are obtained by analyzing the obtained light curves.The second is to find black hole candidates by statistical analysis of the radial velocity data of LAMOST DR8.The following are the main contents of these two areas of work:RS Ser,V449 Per,MR Del,V593 Cen,and V1095 Her are short-period eclipsing binaries.We made photometric observations on 38 nights using four 1-m-class telescopes and plotted eight light curves.We determined the spectral type of V449 Per as K0(±2)V using low-resolution spectra from the Lijiang 2.4-m telescope.We found cyclic variation in the orbital periods of RS Ser and V1095 Her,and confirmed the cyclic variation of MR Del.The periods of the hypothetical third bodies are close to the duration of observation,so the detected cycles are questionable.For V593 Cen,we followed the previously published suggestion that it probably has a black hole with a minimum mass of3.68M_?.The black hole candidate of V593 Cen remains questionable because the minimum points are concentrated in four clusters.The period of V449 Per increases continuously at a rate of 9.5×10-8 d yr–1,which can be attributed to mass transfer from the less massive component to the more massive component.For MR Del,we used a new light curve and the published radial velocity to revise its absolute parameters.Furthermore,we revised the photometric solution of V593Cen and confirmed it as an early-type contact binary with a higher contact factor.We obtained preliminary photometric parameters for RS Ser,V1095 Her,and V449 Per.We use a method proposed by Gu et al.to hunt for black hole candidate in binary systems that contain giant stars.With the database of LAMOST DR8,we found that radial velocity of 13253 systems are variable,in which 16 systems conform to the criterion that radial velocity is larger than 80 km/s.Then we obtain the mass and radius of the 16 systems and estimate the mass and radius of their invisible companions.These systems are very worthy to be observed and investigated further.With the release of various spectral survey and photometric survey data,which provides a data basis for searching for much more black hole candidates,we can predict that more and more black hole candidates could be found.