What do a star look like
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What Do Stars Look Like?
Star Images and Optical Quality of the Human Eye
When observing stars, especially bright point sources in darkness, many people perceive distinctive radiating patterns. These patterns, often referred to as "star images," are primarily caused by diffraction and ocular aberrations within the human eye. Research has shown that when a small Gaussian spot of light is projected onto the retina, the resulting aerial image, viewed through a fully dilated pupil, closely approximates the optical point-spread function of the eye. These images display the characteristic radiating patterns of star images, which match closely with subjective patterns sketched by observers. This supports the hypothesis that these star images have a purely optical origin1.
Profile of a Star Image
The profile of a star image can be described from its central peak out to a radius of six degrees. This profile includes a central core, an exponential drop, and an extended inverse-square aureole. However, the exact origin of this shape is not well understood. The central core represents the brightest part of the star, while the exponential drop and the aureole represent the gradual decrease in brightness as one moves away from the center2.
Appearance of a Collapsing Star
The appearance of a star undergoing gravitational collapse changes over time. As the star collapses, it emits radiation that follows Lambert's cosine law. The spectral photon flux and spectral radiant flux of the star can be calculated, showing that the redshift factor remains finite. Over time, the star becomes gradually invisible due to the decay of the photon flux. This phenomenon is particularly relevant in the study of high-energy neutrinos and other cosmic observations3.
Stars in Magnetic Grand Minima
Stars in a Maunder-like magnetic minimum, a period of low magnetic activity, exhibit different physical and magnetic properties compared to more active stars. These stars can be identified through X-ray observations and other methods. During these periods, stars show reduced magnetic activity, which can be compared to the Sun and other low-activity stars4.
Direct Evidence of Star Structure
The structure of star-like formations, such as star polymers, has been characterized using nuclear magnetic resonance (NMR) spectroscopy. By preparing well-defined polybutadiene and polyisoprene stars and analyzing them with NMR, researchers have observed the core structure next to the silicon atom. This method provides direct evidence of the star's structure, which was previously inferred indirectly5.
Vega-like Stars
Vega-like stars, which show large excess fluxes at 60 microns, have been identified in the Bright Star Catalog. These stars range from spectral types B9 to F6, with a predominance of early A-type stars. Some of these stars are part of multiple systems, and a few show significant darkening between their absolute magnitudes and those estimated from spectral types. This darkening may suggest the presence of circumstellar disks viewed edge-on, similar to the star Beta Pic6.
Conclusion
Stars exhibit a variety of appearances and characteristics depending on their optical profiles, stages of collapse, magnetic activity, and structural properties. From the radiating patterns perceived by the human eye to the detailed profiles and behaviors observed through advanced techniques, the study of star images provides valuable insights into the nature of these celestial bodies.
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Most relevant research papers on this topic
Shape of stars and optical quality of the human eye.
Star images in darkness are primarily optical, with diffraction and ocular aberrations playing a role in their formation.
THE PROFILE OF A STAR IMAGE
The profile of a star image has a central core, exponential drop, and extended inverse-square aureole, with its origin well understood but its shape remains unresolved.
Highly CitedHow does a collapsing star look?
A collapsing star gradually becomes invisible due to decay of photon flux, with the redshift factor remaining finite and the star becoming gradually invisible due to decay of photon flux.
Stars in magnetic grand minima: where are they and what are they like?
Stars in magnetic grand minima have low physical and magnetic activity, and can be found using new X-ray observations.
Direct evidence of star structure from nuclear magnetic resonance spectroscopy
This study provides direct evidence of star structure using nuclear magnetic resonance spectroscopy, revealing the key point of the star, the silicon atom, in polybutadiene and polyisoprene stars with up to four arms.
TWELVE ADDITIONAL "VEGA-LIKE" STARS.
Additional Vega-like stars have been identified, suggesting the presence of circumstellar disks viewed edge-on.
Highly CitedA dusty torus around the luminous young star LkHα101
The inner accretion disk of LkH101 is face-on, with a central gap and hot inner edge, suggesting that the inner edge is likely determined by sublimation of dust grains by direct stellar radiation.
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