Timing of AR CrB eclipses

Kozyreva, V. S.; Irsmambetova, T. R.; Ibrahimov, M.; Krushevska, V. N.; G., Kuznyetsova Yu; Khalikova, A. V.; Parmonov, O. U.; Karimov, R.; Bogomazov, A. I.; Satovskii, B. L.; Тутуков, А. В.

doi:10.22444/ibvs.6235

Cited by 4 publications

(6 citation statements)

References 2 publications

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“…Long-term variations were observed for the spot radius. The light curve variability was similar to that of Zhukov (1983). The spot longitude obtained using this method is precise.…”

Section: Discussionsupporting

confidence: 66%

“…Maceroni et al (1982) determined similar absolute elements of CC Com using the Wilson and Devinney program (Wilson & Devinney 1971), but did not discuss the light curve asymmetry. Furthermore, different maximum values of the light curves were determined in different seasons (Zhukov 1983). McLean & Hilditch (1983) analyzed the radial velocity curves and derived a similar spectroscopic mass ratio.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic activity and orbital parameters of CC Com based on photometric data, LAMOST low- and medium-resolution spectra

Zhu

Zhang

Meng

et al. 2021

Res. Astron. Astrophys.

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In this paper, we present four sets of photometric V RI light curves, and several LAMOST low and medium resolution spectra of contact binary CC Com. We revised the orbital parameters by simultaneously combining with previously published radial velocity measurements using the Wilson-Devinney program. We used light curves at different observational times to obtain the starspot parameters. The values of the starspot radius are variable in short- and long-term scales, and their longitudes are stable. We updated the orbital period change of CC Com, and analyzed the periodic variation. The period of CC Com decreases at a rate of 4.66 (±0.20) × 10−11 d yr−1, which may be due to mass transfer from the secondary component to the primary component. The oscillation of its orbital period with a period of 17.18(0.08) years and amplitude of 0.0018(1) d may be caused by the light time effect (LITE) via a third body of 0.06 M ⊙ dwarf or magnetic activity cycle. Furthermore, we obtained one optical spectrum from the LAMOST survey, which gives the spectral type of CC Com as K7±2V. Strong emissions exist in the Hα, and Ca ii H&K lines in the observed spectrum, indicating strong chromospheric activity on CC Com. In the 12 LAMOST medium-resolution spectra, the EWs of Hα line are variable along the phase and time, which may be a plage or flare event.

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“…Long-term variations were observed for the spot radius. The light curve variability was similar to that of Zhukov (1983). The spot longitude obtained using this method is precise.…”

Section: Discussionsupporting

confidence: 66%

Section: Introductionmentioning

confidence: 99%

Magnetic activity and orbital parameters of CC Com based on photometric data, LAMOST low- and medium-resolution spectra

Zhu

Zhang

Meng

et al. 2021

Res. Astron. Astrophys.

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“…This RS CVn classification appears to be erroneous and can be traced to time series photometric observations which used a fast-rotating spotted star as a photometric standard. Fisher et al (1983) reported δ Eri to be a suspected RS CVn variable based on detection of ∼0.02 mag amplitude variability with period ∼10 days. Unfortunately the observations used Eri as a photometric standard, itself a spotted variable star with P rot 10-12 d and variability at the ∼0.01-0.03 mag level (Frey et al 1991;Croll et al 2006).…”

Section: Hd 23249 (δ Eri)mentioning

confidence: 99%

Doppler Constraints on Planetary Companions to Nearby Sun-like Stars: An Archival Radial Velocity Survey of Southern Targets for Proposed NASA Direct Imaging Missions

Laliotis¹,

Burt²,

Mamajek³

et al. 2023

Preprint

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Directly imaging temperate rocky planets orbiting nearby, Sun-like stars with a 6-m-class IR/O/UV space telescope, recently dubbed the Habitable Worlds Observatory, is a high priority goal of the Astro2020 Decadal Survey. To prepare for future direct imaging surveys, the list of potential targets should be thoroughly vetted to maximize efficiency and scientific yield. We present an analysis of archival radial velocity data for southern stars from the NASA/NSF Extreme Precision Radial Velocity Working Group's list of high priority target stars for future direct imaging missions (drawn from the HabEx, LUVOIR, and Starshade Rendezvous studies). For each star, we constrain the region of companion mass and period parameter space we are already sensitive to based on the observational baseline, sampling, and precision of the archival RV data. Additionally, for some of the targets we report new estimates of magnetic activity cycle periods, rotation periods, improved orbital parameters for previously known exoplanets, and new candidate planet signals that require further vetting or observations to confirm. Our results show that for many of these stars we are not yet sensitive to even Saturn-mass planets in the habitable zone, let alone smaller planets, highlighting the need for future EPRV vetting efforts before the launch of a direct imaging mission. We present evidence that the

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“…It is also the first known and a heavily studied variable star in this OC. Its variability was discovered by Kurochkin (1960), and was later identified as a W UMa system by Efremov et al (1964). Interestingly, this binary was once misclassified as an RR Lyrae variable star by Kurochkin (1960), which was later noted by Maceroni et al (1984) who reported that this system is actually a W-type overcontact binary system instead.…”

Section: Introductionmentioning

confidence: 95%

Photometric solution and period analysis of the contact binary system AH Cnc

Peng

Zhi-Quan

Zhang

et al. 2016

Res. Astron. Astrophys.

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Photometric observations of AH Cnc, a W UMa-type system in the open cluster M67, were carried out by using the 50BiN telescope. About 100 h of time-series Band V -band data were taken, based on which eight new times of light minima were determined. By applying the Wilson-Devinney method, the light curves were modeled and a revised photometric solution of the binary system was derived. We confirmed that AH Cnc is a deep contact (f = 51%), low mass-ratio (q = 0.156) system. Adopting the distance modulus derived from study of the host cluster, we have re-calculated the physical parameters of the binary system, namely the masses and radii. The masses and radii of the two components were estimated to be respectively 1.188(±0.061) M ⊙ , 1.332(±0.063) R ⊙ for the primary component and 0.185(±0.032) M ⊙ , 0.592(±0.051) R ⊙ for the secondary. By adding the newly derived minimum timings to all the available data, the period variations of AH Cnc were studied. This shows that the orbital period of the binary is continuously increasing at a rate of dp/dt = 4.29 × 10 −10 d yr −1 . In addition to the long-term period increase, a cyclic variation with a period of 35.26 yr was determined, which could be attributed to an unresolved tertiary component of the system.

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Timing of AR CrB eclipses

Cited by 4 publications

References 2 publications

Magnetic activity and orbital parameters of CC Com based on photometric data, LAMOST low- and medium-resolution spectra

Magnetic activity and orbital parameters of CC Com based on photometric data, LAMOST low- and medium-resolution spectra

Doppler Constraints on Planetary Companions to Nearby Sun-like Stars: An Archival Radial Velocity Survey of Southern Targets for Proposed NASA Direct Imaging Missions

Photometric solution and period analysis of the contact binary system AH Cnc

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