Related papers: CSS J134052.0+151341 : A Cataclysmic Binary Star w…

The atmosphere of the extremely high-velocity (530-920 km/s) early B-type star HD271791 is enriched in $\alpha$-process elements, which suggests that this star is a former secondary component of a massive tight binary system and that its…

We report the results from follow-up observations of two Roche-lobe filling hot subdwarf binaries with white dwarf companions predicted to have accretion disks. ZTF J213056.71+442046.5 (ZTF J2130) with a 39-minute period and ZTF…

We analyze extensive BVRI photometry and radial velocity measurements for three double-lined deeply-eclipsing binary stars in the field of the old open cluster NGC 7142. The short period (P = 1.9096825 d) detached binary V375 Cep is a high…

SDSSJ125733.63+542850.5 (hereafter SDSSJ1257+5428) is a compact white dwarf binary from the Sloan Digital Sky Survey that exhibits high-amplitude radial velocity variations on a period of 4.56 hours. While an initial analysis suggested the…

We report the discovery of a relatively bright eclipsing binary system, which consists of a white dwarf and a main sequence K7 star with clear signs of chromospheric and spot activity. The light curve of this system shows $\sim0.2$mag…

The first B-, V-, Rc-, and Ic-band light curves of CSS J022914.4+044340 are presented and analyzed. It is found that CSS J022914.4+044340 is a low mass ratio (0.198 +- 0.005) deep (63.7 +- 7.9%) contact binary, indicating that it has been…

An eclipsing binary with an orbital period of 62 days has been discovered in HD 328058 and studied by UBVIcHalpha photometry. Combining the results of light curve modelling with existing stellar models and known B3-shell spectral type of…

We report the discovery of a compact, coplanar, quadruply-lined, eclipsing quadruple star system from TESS data, TIC 454140642, also known as TYC 0074-01254-1. The target was first detected in Sector 5 with 30-min cadence in Full-Frame…

We report on extended photometry of two pulsating sdB stars in close binaries. For both cases, we use rotational splitting of the pulsation frequencies to show that the sdB component rotates much too slowly to be in synchronous rotation. We…

We present an analysis of nine bright spectroscopic binaries (HD 1585, HD 6613, HD 12390, HD 39923, HD 55201, HD 147430, HD 195543, HD 202699, HD 221643), which have orbital periods of P > 500 days. These well-separated binaries are the…

In this paper, CCD photometric light curves for the short-period eclipsing binary 1SWASP J140533.33+114639.1 (hereafter J1405) in the $BVR$ bands are presented and analyzed using the 2013 version of the Wilson-Devinney (W-D) code. It is…

We present spectroscopy of four cataclysmic variables. Using radial velocity measurements, we find orbital periods for the first time. The stars and their periods are GY Hya, 0.347230(9) d; SDSS J204448-045929, 1.68(1) d; V392 Hya,…

We report optical time-resolved photometry of the CRTS transient CSS091109:035759+102943. Pronounced orbital variability with a 114 min period, large X-ray variability and the IR to X-ray spectral energy distribution suggest a…

We report follow-up observations of five cataclysmic variable candidates from LAMOST published by Hou et al. (2020). LAMOST J024048.51+195226.9 is the most unusual of the five; an early-M type secondary star contributes strongly to its…

We present follow-up photometry and spectroscopy of ZTF J0328$-$1219 strengthening its status as a white dwarf exhibiting transiting planetary debris. Using TESS and Zwicky Transient Facility photometry, along with follow-up high speed…

We present follow-up studies of three ultracompact hot subdwarf binaries. Using data from the Zwicky Transient Facility, we find orbital periods of 33.6, 37.3, and 36.9 minutes for ZTF 1946+3203, ZTF 0640+1738, and ZTF 0643+0318…

We studied two objects identified as a Cataclysmic Variables (CVs) with periods exceeding the natural boundary for Roche lobe filling ZAMS secondary stars. We present observational results for V1082 Sgr with 20.82 h orbital period, an…

We obtained high-resolution spectra and multicolor photometry of V1082 Sgr to study the donor star in this 20.8 hr orbital period binary, which is assumed to be a detached system. We measured the rotational velocity (v sin i = 26.5+/-2.0…

We report on the results of high dispersion spectroscopy of two `superflare stars', KIC 9766237, and KIC 9944137 with Subaru/HDS. Superflare stars are G-type main sequence stars, but show gigantic flares compared to the Sun, which have been…

The 11th magnitude star LS IV -08 3 has been classified previously as an OB star in the Luminous Stars survey, or alternatively as a hot subdwarf. It is actually a binary star. We present spectroscopy, spectroscopic orbital elements, and…