Related papers: R Coronae Borealis Stars at Minimum Light -- UW Ce…
We are undertaking the first systematic infrared (IR) census of R Coronae Borealis (RCB) stars in the Milky Way, beginning with IR light curves from the Palomar Gattini IR (PGIR) survey. PGIR is a 30 cm $J$-band telescope with a 25…
The high resolution optical spectra of H-deficient stars, R Coronae Borealis stars and H-deficient carbon stars are analyzed by synthesizing the C2 Swan bands (0,1), (0,0), and (1,0) using our detailed line-list and Uppsala model…
NSV 11154 has been confirmed as a new member of the rare hydrogen deficient R Coronae Borealis (RCB) stars based on new photometric and spectroscopic data. Using new photometry, as well as archival plates from the Harvard archive, we have…
Context. RW Aur A is a classical T Tauri star (CTTS) with an unusually rich emission line spectrum. In 2014 the star faded by ~ 3 magnitudes in the V band and went into a long-lasting minimum. In 2010 the star suffered from a similar…
RW Aur is a young binary star that experienced a deep dimming in 2010-11 in component A and a second even deeper dimming from summer 2014 to summer 2016. We present new unresolved multi-band photometry during the 2014-16 eclipse, new…
We search high-resolution and high-quality VLT/UVES optical spectra of the hot R Coronae Borealis (RCB) star DY Cen for electronic transitions of the C60 molecule and diffuse interstellar bands (DIBs). We report the non-detection of the…
Optical and near-IR photometry suggests that the carbon star DY Persei exhibits fadings similar to those of R Coronae Borealis (RCB) variables. Photometric surveys of the Galaxy and Magellanic Clouds uncovered new DY Per variables with…
We present results of follow-up optical spectroscopic observations of seven rare, extreme coronal line emitting galaxies reported by Wang et al. (2012) with Multi-Mirror Telescope (MMT). Large variations in coronal lines are found in four…
RW Aur is a binary system composed of two young, low-mass stars. The primary, RW Aur A, has undergone visual dimming events ($\Delta V =2-3$~mag) in 2011, 2014-16, and 2017-2018. Visual and IR observations indicate a gray absorber that…
The secondary of the famous young binary RW Aur is much less studied than the primary. To compensate this shortcoming, we present here the results of UBVRIJHK photometric, VRI polarimetric and optical spectral observations of RW Aur B. The…
We have carried out a search for new R Coronae Borealis (RCB) variables using the publicly accessible data from various photometric sky surveys and-whenever available-AAVSO visual data. Candidates were selected from Tisserand`s "Catalogue…
We report our search for variability in the H-alpha emission line of the recurrent novae T CrB with time resolution 10-15 minutes. This is comparable with the time scale of the photometric flickering observed in this object. This is the…
There are only about 65 R Coronae Borealis stars known in our Galaxy, and none in globular clusters. As these stars are thought to result from the merger of two white dwarfs, one would expect the higher stellar density of globular clusters…
The spectra of RR Tau star, which belongs to the family of young irregular variable UX Ori type stars, in its different brightness states have been studied using a comparative analysis. Selected spectra of the star that are obtained with…
We present a new theoretical estimate for the birthrate of R Coronae Borealis (RCB) stars that is in agreement with recent observational data. We find the current Galactic birthrate of RCB stars to be $\approx$ 25% of the Galactic rate of…
The hydrogen-poor, helium-rich and carbon-rich character of the gas around R Coronae Borealis (RCB) stars has been suggested to be a site for formation of C60 molecules. This suggestion is not supported by observations reported here showing…
Context: R Coronae Borealis (RCB) variables and their non-variable counterparts, the dustless Hydrogen-Deficient Carbon (dLHdC) stars have been known to exhibit enhanced s-processed material on their surfaces, especially Sr, Y, and Ba. No…
Aims. R Coronae Australis (R CrA) is the brightest star of the Coronet nebula of the Corona Australis (CrA) star forming region. It has very red colors, probably due to dust absorption and it is strongly variable. High contrast instruments…
T CrB is a symbiotic star that experiences nova outbursts every $\sim$ 80~yr. The next, long-anticipated nova outburst should occur during the 2024-2026 period. Here, we present results of high-resolution optical spectroscopy of T CrB in…
Observed spectra of R Coronae Borealis (RCB) and hydrogen-deficient carbon (HdC) stars are analyzed by synthesizing the C2 Swan bands (1,0), (0,0), and (0,1) using our detailed line list and the Uppsala model atmospheres. The (0,1) and…