Direct imaging of a massive dust cloud around R Coronae Borealis

  title={Direct imaging of a massive dust cloud around R Coronae Borealis},
  author={S. V. Jeffers and Michiel Min and L. B. F. M. Waters and H{\'e}ctor C{\'a}novas and Michiel Rodenhuis and Maria de Juan Ovelar and Ana L. Chies-Santos and Christoph U. Keller},
  journal={Astronomy and Astrophysics},
We present recent polarimetric images of the highly variable star R CrB using ExPo and archival WFPC2 images from the HST. We observed R CrB during its current dramatic minimum where it decreased more than 9 mag due to the formation of an obscuring dust cloud. Since the dust cloud is only in the line-of-sight, it mimics a coronograph allowing the imaging of the star’s circumstellar environment. Our polarimetric observations surprisingly show another scattering dust cloud at approximately 1.3… 

Figures and Tables from this paper

Surprising detection of an equatorial dust lane on the AGB star IRC+10216

Aims. Understanding the formation of planetary nebulae remains elusive because in the preceding asymptotic giant branch (AGB) phase these stars are heavily enshrouded in an optically thick dusty

Imaging the circumstellar environment of the young T Tauri star SU Aurigae

The circumstellar environments of classical T Tauri stars are challenging to directly image because of their high star-to-disk contrast ratio. One method to overcome this is by using imaging

ROAD† and K2 photometry of V348 Sgr: probing the pulsation dust connection

V348 Sgr is simultaneously an active hot R Coronae Borealis (RCB) variable, a peculiar extreme helium star, and the hydrogen-deficient central star of a planetary nebula. Explaining the RCB-type


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

Detection of an asymmetry in the envelope of the carbon Mira R Fornacis using VLTI/MIDI ,

Aims. We present a study of the envelope morphology of the carbon Mira R For with VLTI/MIDI. This object is one of the few asymptotic giant branch (AGB) stars that underwent a dust-obscuration event.

Imaging diagnostics for transitional discs

Transitional discs are a special type of protoplanetary disc, where planet formation is thought to be taking place. These objects feature characteristic inner cavities and/or gaps of a few tens of

The curious case of II Lup: a complex morphology revealed with SAM/NACO and ALMA

We present the first-ever images of the circumstellar environment of the carbon-rich AGB star II Lup in the infrared and sub-mm wavelengths, and the discovery of the envelope's non-spherical

Nonazimuthal linear polarization in protoplanetary disks

Several studies discussing imaging polarimetry observations of protoplanetary disks use the so-called radial Stokes parameters Q_phi and U_phi to discuss the results. This approach has the advantage

R Coronae Borealis: radial velocity and other observations, 1950–2007

Radial-velocity observations made on more than a thousand nights are presented for the type star of the R Coronae Borealis (RCB) class. There are four principal sources: the Lick Observatory

Constraints on positron annihilation kinematics in the inner Galaxy

Context. The annihilation of cosmic positrons with electrons in the interstellar medium results in the strongest persistent γ-ray line signal in the sky. For the past 50 yr, this 511 keV emission –



A snapshot of the inner dusty regions of a R CrB-type variable ,

Context. R Coronae Borealis (R CrB) variable stars are suspected to sporadically eject optically thick dust clouds causing, when one of them lies on the line-of-sight, a huge brightness decline in

First detection of dust clouds around R CrB variable stars

From VLT/NACO diffraction-limited images of RY~Sgr, we report the first direct detection of heterogeneities in the circumstellar envelope of a R Coronae Borealis variable star. Several bright and

Very large telescope interferometer observations of the dust geometry around R Coronae Borealis stars

We are investigating the formation and evolution of dust around the hydrogen-deficient supergiants known as R Coronae Borealis (RCB) stars. We aim to determine the connection between the probable


In 2007, R Coronae Borealis (R CrB) went into a historically deep and long decline. In this state, the dust acts like a natural coronagraph at visible wavelengths, allowing faint nebulosity around

Winds in R Coronae Borealis Stars

We present new spectroscopic observations of the He I λ10830 line in R Coronae Borealis (RCB) stars that provide the first strong evidence that most, if not all, RCB stars have winds. It has long

Diffraction-Limited Speckle Interferometry and Modeling of the Circumstellar Envelope of R CrB at Maximum and Minimum Light

We present the rst speckle interferometric observations of R CrB, the prototype of a class of peculiar stars which undergo irregular declines in their visible light curves. The observations were

Evidence for a Bipolar Geometry in R Coronae Borealis?

The R Coronae Borealis (RCB) stars produce dust at irregular intervals, but the distribution of the circumstellar material is not known. We report spectropolarimetry of R Coronae Borealis (R CrB)


This year marks the bicentennial of the discovery of the variability of R Coronae Borealis. The R Coronae Borealis (RCB) stars are distinguished from other hydrogen-deficient objects by their

UBVJHKLM photometry and modeling of R Coronae Borealis

We present the results of UBVJHKLMphotometry of R CrB spanning the period from 1976 to 2001. Studies of the optical light curve have shown no evidence of any stable harmonics in the variations of the

Spectropolarimetry of V854 Centauri at minimum light - Clues to the geometry of the dust and emission-line region

The RCB star V854 Cen is observed during a very deep decline (Delta m = 8.2) at the AAT. The continuum polarization is very high, ranging from 14 percent at 4200 A to about 4 percent at 6500 A. The