Results from UBVRI optical photometric observations of the pre-main se- quence star V350 Cep during the period 2004-2014 are presented. The star was dis- covered in 1977 due to its remarkable increase in brightness by...Results from UBVRI optical photometric observations of the pre-main se- quence star V350 Cep during the period 2004-2014 are presented. The star was dis- covered in 1977 due to its remarkable increase in brightness by more than 5 mag （R）. In previous studies, V350 Cep was considered to be a potential FUor or EXor eruptive variable. Our data suggest that during the period of observations the star maintains its maximum brightness with low amplitude photometric variations. Our conclusion is that V350 Cep was probably an intermediate object between FUors and EXors, similar to V1647 Ori.展开更多
The first photometric analysis of V811 Cep was carried out.The first complete light curves of V,R and I bands are given.The analysis was carried out by the Wilson-Devinney(W-D)program,and the results show that V811 Ce...The first photometric analysis of V811 Cep was carried out.The first complete light curves of V,R and I bands are given.The analysis was carried out by the Wilson-Devinney(W-D)program,and the results show that V811 Cep is a median-contact binary(f=33.9(±4.9)%)with a mass ratio of 0.285.It is a W-subtype contact binary,that is,the component with less mass is hotter than the component with more mass,and the light curves are asymmetric(O’Connell effect),which can be explained by the existence of a hot spot on the component with less mass.The orbital inclination is i=88.3°,indicating that it is a totally eclipsing binary,so the parameters obtained are reliable.Through the O-C analyzing,it is found that the orbital period decreases at the rate of P=-3.90(±0.06)×10^(-7)d yr^(-1),which indicates that the mass transfer occurs from the more massive component to the less massive one.展开更多
Photometric observations in Sloan g′and i′bands of four W UMa binaries, V796 Cep,V797 Cep, CSS J015341.9＋381641 and NSVS 3853195, are presented. Our observations showed that CSS J015404.1＋382805 and NSVS 3853195 a...Photometric observations in Sloan g′and i′bands of four W UMa binaries, V796 Cep,V797 Cep, CSS J015341.9＋381641 and NSVS 3853195, are presented. Our observations showed that CSS J015404.1＋382805 and NSVS 3853195 are the same star. We determined the initial epochs T_0 of all targets and found improved values for the period of NSVS 3853195. The light curve solutions of our data revealed that the components of each target are almost the same in terms of mass, temperature,radius and luminosity. The stellar components are G and K spectral types and undergo partial eclipses.All systems have barely-overcontact configurations and can be classified as H subtype W UMa binaries.We established that the relation between the luminosity ratio l_2/l_1 and mass ratio q of our targets is approximately l_2/l_1 = q^（1.5）.展开更多
Long-term BVRI photometric light curves of the pre-main sequence stars V977 Cep and V982 Cep during the period from 2000 October to 2016 August are presented. The stars are located in the vicinity of the reflection ne...Long-term BVRI photometric light curves of the pre-main sequence stars V977 Cep and V982 Cep during the period from 2000 October to 2016 August are presented. The stars are located in the vicinity of the reflection nebula NGC 7129. Our photometric data show that both stars exhibit strong photometric variability in all optical passbands, which is typical for Classical T Tauri stars. Using our observational data we analyze the reasons for the observed brightness variations. In the case of V977 Cep we identify previously unknown periodicity in its light curve.展开更多
V0842 Cep is a W UMa-type binary star that has been neglected since its discovery.We analysed the V RcIc light curves,obtained by the 1 m telescope at Weihai Observatory of Shandong University,using the Wilson-Devinne...V0842 Cep is a W UMa-type binary star that has been neglected since its discovery.We analysed the V RcIc light curves,obtained by the 1 m telescope at Weihai Observatory of Shandong University,using the Wilson-Devinney code.V0842 Cep was found to be a shallow contact binary system(f=8.7%)with a mass ratio of 2.281.Because its orbital inclination is greater than 80◦,the photometric results are reliable.A period study is included which reveals a continually decreasing orbital period(dp/dt=1.50(±0.42)×10^(−7)d y^(r−1)).This trend could be attributed to the angular momentum loss via stellar wind.展开更多
基金supported by ESF and the Bulgarian Ministry of Education and Science under the contract BG051PO001-3.3.06-0047
文摘Results from UBVRI optical photometric observations of the pre-main se- quence star V350 Cep during the period 2004-2014 are presented. The star was dis- covered in 1977 due to its remarkable increase in brightness by more than 5 mag （R）. In previous studies, V350 Cep was considered to be a potential FUor or EXor eruptive variable. Our data suggest that during the period of observations the star maintains its maximum brightness with low amplitude photometric variations. Our conclusion is that V350 Cep was probably an intermediate object between FUors and EXors, similar to V1647 Ori.
基金supported by the Joint Research Fund in Astronomy(No.U1931103)under cooperative agreement between the National Natural Science Foundation of China(NSFC)and Chinese Academy of Sciences(CAS)by NSFC(No.11703016)+1 种基金by Young Scholars Program of Shandong University,Weihai(No.20820171006)by the Open Research Program of Key Laboratory for the Structure and Evolution of Celestial Objects(No.OP201704)。
文摘The first photometric analysis of V811 Cep was carried out.The first complete light curves of V,R and I bands are given.The analysis was carried out by the Wilson-Devinney(W-D)program,and the results show that V811 Cep is a median-contact binary(f=33.9(±4.9)%)with a mass ratio of 0.285.It is a W-subtype contact binary,that is,the component with less mass is hotter than the component with more mass,and the light curves are asymmetric(O’Connell effect),which can be explained by the existence of a hot spot on the component with less mass.The orbital inclination is i=88.3°,indicating that it is a totally eclipsing binary,so the parameters obtained are reliable.Through the O-C analyzing,it is found that the orbital period decreases at the rate of P=-3.90(±0.06)×10^(-7)d yr^(-1),which indicates that the mass transfer occurs from the more massive component to the less massive one.
基金supported partly by grants ND08/20 and RD 08-102 of the Fund for Scientific Research of the Bulgarian Ministry of Education and Sciencefunded by the National Aeronautics+1 种基金Space Administration and the National Science Foundationsupported partly by funds from project RD 02–81 of Shumen University
文摘Photometric observations in Sloan g′and i′bands of four W UMa binaries, V796 Cep,V797 Cep, CSS J015341.9＋381641 and NSVS 3853195, are presented. Our observations showed that CSS J015404.1＋382805 and NSVS 3853195 are the same star. We determined the initial epochs T_0 of all targets and found improved values for the period of NSVS 3853195. The light curve solutions of our data revealed that the components of each target are almost the same in terms of mass, temperature,radius and luminosity. The stellar components are G and K spectral types and undergo partial eclipses.All systems have barely-overcontact configurations and can be classified as H subtype W UMa binaries.We established that the relation between the luminosity ratio l_2/l_1 and mass ratio q of our targets is approximately l_2/l_1 = q^（1.5）.
基金supported partly by funds of the project‘Multicolor photometric study of Pre-main sequence stars from selected star-forming regions’financed by Fund for Scientific Research of the Bulgarian Ministry of Education and Scienceuse of NASA’s Astrophysics Data System Abstract Service+2 种基金the SIMBAD database and the Vizie R catalogue access tool,operated at CDS,Strasbourg,Francefunded by the National Aeronautics and Space Administration and the National Science Foundation(Skrutskie et al.2006)supported partly by funds from the project RD-08-81 at the University of Shumen
文摘Long-term BVRI photometric light curves of the pre-main sequence stars V977 Cep and V982 Cep during the period from 2000 October to 2016 August are presented. The stars are located in the vicinity of the reflection nebula NGC 7129. Our photometric data show that both stars exhibit strong photometric variability in all optical passbands, which is typical for Classical T Tauri stars. Using our observational data we analyze the reasons for the observed brightness variations. In the case of V977 Cep we identify previously unknown periodicity in its light curve.
基金This work is supported by the Joint Research Fund in Astronomy(Grant No.U1931103)under cooperative agreement between National Natural Science Foundation of China(NSFC)Chinese Academy of Sciences(CAS),the NSFC(Grant No.11703016)+2 种基金the Natural Science Foundation of Shandong Province(Grant No.ZR2014AQ019)the Young Scholars Program of Shandong University,Weihai(Grant No.20820171006)the Chinese Academy of Sciences Interdisciplinary Innovation Team,and by the Open Research Program of Key Laboratory for the Structure and Evolution of Celestial Objects(Grant No.OP201704).
文摘V0842 Cep is a W UMa-type binary star that has been neglected since its discovery.We analysed the V RcIc light curves,obtained by the 1 m telescope at Weihai Observatory of Shandong University,using the Wilson-Devinney code.V0842 Cep was found to be a shallow contact binary system(f=8.7%)with a mass ratio of 2.281.Because its orbital inclination is greater than 80◦,the photometric results are reliable.A period study is included which reveals a continually decreasing orbital period(dp/dt=1.50(±0.42)×10^(−7)d y^(r−1)).This trend could be attributed to the angular momentum loss via stellar wind.
