Related papers: Vega is a rapidly rotating star
The central star of the planetary nebula NGC 1514 is among the visually brightest central stars in the sky (V=9.5). It has long been known to show a composite spectrum, consisting of an A-type star and a much hotter star responsible for the…
Massive stars live fast and die young. They shine furiously for a few million years, during which time they synthesize most of the heavy elements in the universe in their cores. They end by blowing themselves up in a powerful explosion…
We present sub-millimeter and mid-infrared images of the circumstellar disk around the nearby F2V star eta Corvi. The disk is resolved at 850um with a size of ~100AU. At 450um the emission is found to be extended at all position angles,…
The light variability of hot magnetic chemically peculiar stars is typically caused by the flux redistribution in spots with peculiar abundance. This raises the question why some stars with surface abundance spots show significant…
Vega and Fomalhaut, are similar in terms of mass, ages, and global debris disk properties; therefore, they are often referred as "debris disk twins". We present Spitzer 10-35 um spectroscopic data centered at both stars, and identify warm,…
Polarization is a powerful tool for understanding stellar atmospheres and circumstellar environments. Mira and semi-regular variable stars have been observed for decades and some are known to be polarimetrically variable, however, the…
Charged particles at the crust of compact stars may be ejected and accelerated by the electric field generated due to the rotation of the magnetized star. For neutron or hybrid stars, the negatively charged particles are usually electrons,…
Gravitational radiation drives an instability in the r-modes of young rapidly rotating neutron stars. This instability is expected to carry away most of the angular momentum of the star by gravitational radiation emission, leaving a star…
Polar vortices are common in the atmospheres of rapidly rotating planets [1-4]. On Earth and Mars they are tied to the surface and their existence follows the seasonal insolation cycle [1-3]. Venus is a slowly rotating planet but it is also…
Compared to starburst galaxies, normal star forming galaxies have been shown to display a much larger dispersion of the dust attenuation at fixed reddening through studies of the IRX-beta diagram (the IR/UV ratio "IRX" versus the UV color…
The far-ultraviolet is the most rapidly evolving portion of the spectrum in both very young galaxies and very old galaxies. The ``UV upturn'' in the spectra of elliptical galaxies shortward of 2000 Angstroms offers a promising probe of the…
A long standing problem in high energy astrophysics is the nature of galactic accelerators of particles with energies above PeV. Such objects are sources of galactic cosmic rays and can produce PeV-regime photons observed by ground-based…
We present new narrow-band filter imagery in H-alpha and [N II] 6584 along with UV and optical spectrophotometry measurements from 1200 to 9600 Angstroms of NGC 7293, the Helix Nebula, a nearby, photogenic planetary nebula of large diameter…
We have obtained accurate circular spectropolarimetric observations for a sample of Vega-like and Herbig Ae/Be stars with FORS1 at the VLT in an attempt to detect their magnetic fields. No magnetic field could be diagnosed in any Vega-like…
The James Webb Space Telescope (JWST) has revealed an unexpectedly high abundance of UV luminous galaxies at redshifts $z\gtrsim 10$, challenging `standard' galaxy formation models. This study investigates the role of rapidly rotating…
Through Spitzer Space Telescope's observations, Su et al. (2005) show that the Vega debris disc is dominated by grains which are small enough to be blown out by radiation pressure. This implies the lifetime of Vega debris disc's grains is…
A radial velocity (RV) survey to detect central stars in binary systems was carried out between 2002 and 2004. De Marco et al. (2004) reported that 10 out of 11 monitored stars exhibited strong RV variability, but periods were not detected.…
Spatially resolving the surfaces of nearby stars promises to advance our knowledge of stellar physics. Using optical long-baseline interferometry, we present here a near-infrared image of the rapidly rotating hot star Altair with <1…
For the first time high-resolution optical spectroscopy of the variable star V2324Cyg associated with the IR-source IRAS20572+4919 is made. More than 200 absorption features (mostly FeII, TiII, CrII, YII, BaII, and YII) are identified…
Thermal radiation becomes a prominent feature in the continuum spectrum of Venus longwards of $\sim$3 $\mu$m. The emission is traceable to the upper cloud and haze layers in the planet's mesosphere. Venus' thermal radiation spectrum is…