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TW Coronae Borealis (TW CrB) is a binary system likely to be active showing evidence of starspots and a hotspot. We calculated a new ephemeris based on all available timings from 1946 and find the period to be 0.58887492(2) days. We have revised the average rate of change of period down from 1.54(16) x 10-7 days yr-1 to 6.66(14) x10-8 days yr-1. Based on light curve simulation analysis we conclude that the two stars are close to filling their Roche lobes, or possibly that one of the stars Roche lobe has been filled. The modelling also led to a hotspot and two starspots being identified. Conservative mass transfer is one of a number of possible mechanisms considered that could explain the change in period, but the mass transfer rate would be significantly lower than previous estimates. We found evidence that suggests the period was changing in a cyclical manner, but we do not have sufficient data to make a judgement on the mechanism causing this variation. The existence of a hotspot suggests mass transfer with a corresponding increase in the amplitude in the B band as compared with the R and V bands. The chromospheric activity implied by the starspots make this binary a very likely X-ray source.
The stellar content of Galactic open clusters is gradually depleted during their evolution as a result of internal relaxation and external interactions. The final residues of the evolution of open clusters are called open cluster remnants, barely dis
We analyze high angular resolution ALMA observations of the TW Hya disk to place constraints on the CO and dust properties. We present new, sensitive observations of the $^{12}$CO $J = 3-2$ line at a spatial resolution of 8 AU (0farcs14). The CO emis
We report observations of the cyanide anion, CN, in the disk around TW~Hya covering the $N=1-0$, $N=2-1$ and $N=3-2$ transitions. Using line stacking techniques, 24 hyperfine transitions are detected out of the 30 within the observed frequency ranges
We present the multi-color, five-year light curves and the first radial velocities of the near-contact binary system KR Cyg. We derived the masses of the components as 2.88$pm$0.20 M$_{odot}$ and 1.26$pm$0.07 M$_{odot}$ and the radii as 2.59$pm$0.06
A high angular resolution near-infrared polarized-intensity image of the GG Tau A binary system was obtained with the Subaru Telescope. The image shows the circumbinary disk scattering the light from the central binary. The azimuthal profile of the p