Cosma Home > Communication > Knowledge > Realm > Physical > Universe > Planetary System > Star
Spotlight
Related
Pages
Physical Realm
Universe Astronomical Instrument
Galaxy Milky Way, Andromeda
Planetary System Star, Brown Dwarf, Planet, Moon
Solar System Sun
Terrestrial Planet Mercury, Venus, Earth (Moon), Mars
Asteroid Belt Ceres, Vesta
Jovian Planet Jupiter, Saturn, Uranus, Neptune
Trans-Neptunian Object
Kuiper Belt Pluto, Haumea, Makemake
Scattered Disc Eris, Sedna, Planet X
Oort Cloud Etc. Scholz’s Star
Small Body Comet, Centaur, Asteroid
Posts
- Touch the Sun (12/6/2019) - Remember how Icarus wanted to touch the Sun, but met his demise instead? Well, scientists at NASA wanted to touch the Sun too, but unlike Icarus, they succeeded! Better yet, they are beginning to share what they learned by doing it! Before we get into all of that, let’s go back and start at the … Continue reading Touch the Sun
- Halloween@NASA (10/31/2019) - The folks at NASA love Halloween, and they do something to celebrate every year. For example, the engineers at NASA Jet Propulsion Lab have been holding a pumpkin carving contest for almost a decade, and stories about their ingenuity invariably make it into the news. Here’s a video from Wired about their 2016 competition. Here’s … Continue reading Halloween@NASA
- Get Lost in Space! (9/14/2018) - Way back in August, in anticipation of the start of a new school year, I set out to update the pages on this site related to space. Those pages tend to be popular among the teachers and students who use Cosma, and I happen to enjoy updating them, too. It sounded like a short, fun … Continue reading Get Lost in Space!
- Milky Way Lost & Found (8/15/2018) - Have you seen the Milky Way? You may think that you have, but are you sure? Unless you live in an extremely remote area, or you’ve visited one, then you probably haven’t seen our own galaxy, the Milky Way, very well, or at all. Worse yet, you may not even realize that it’s missing. The … Continue reading Milky Way Lost & Found
- Umbraphiles (8/20/2017) - umbraphile : One who loves eclipses, often travelling to see them. — Wiktionary Yes, this is that obligatory post about “The Solar Eclipse” (NASA, Wikipedia). Of course, there had to be one — eclipses really are just too cool to ignore. You’ve already been bombarded with explanations of the science and history of eclipses, but … Continue reading Umbraphiles
- TRAPPIST-1 (2/23/2017) - You’ve probably heard that NASA has found a trove of “Earth-like” planets circling the TRAPPIST-1 system roughly 40 light years away, but just in case you haven’t, here’s a short 2 minute AP video about the discovery. Here’s another video from NASA/JPL with more explanation. Most entertainingly, here’s a 360° YouTube Video published by NASA/JPL … Continue reading TRAPPIST-1
Resources
These are organized by a classification scheme developed exclusively for Cosma. More…
General
Portal
Stars Reference (National Geographic)
Star Portal (Wikipedia)
Dictionary
star : a self-luminous gaseous spheroidal celestial body of great mass which produces energy by means of nuclear fusion reactions — Webster
OneLook, Free Dictionary, Wiktionary, Urban Dictionary
Thesaurus
Roget’s II (Thesaurus.com), Merriam-Webster Thesaurus, Visuwords
Encyclopedia
Star is a luminous sphere of plasma held together by its own gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye from Earth during the night, appearing as a multitude of fixed luminous points in the sky due to their immense distance from Earth. Historically, the most prominent stars were grouped into constellations and asterisms, the brightest of which gained proper names. Astronomers have assembled star catalogues that identify the known stars and provide standardized stellar designations. However, most of the stars in the Universe, including all stars outside our galaxy, the Milky Way, are invisible to the naked eye from Earth. Indeed, most are invisible from Earth even through the most powerful telescopes.
For at least a portion of its life, a star shines due to thermonuclear fusion of hydrogen into helium in its core, releasing energy that traverses the star’s interior and then radiates into outer space. Almost all naturally occurring elements heavier than helium are created by stellar nucleosynthesis during the star’s lifetime, and for some stars by supernova nucleosynthesis when it explodes. Near the end of its life, a star can also contain degenerate matter. Astronomers can determine the mass, age, metallicity (chemical composition), and many other properties of a star by observing its motion through space, its luminosity, and spectrum respectively. The total mass of a star is the main factor that determines its evolution and eventual fate. Other characteristics of a star, including diameter and temperature, change over its life, while the star’s environment affects its rotation and movement. A plot of the temperature of many stars against their luminosities produces a plot known as a Hertzsprung–Russell diagram (H–R diagram). Plotting a particular star on that diagram allows the age and evolutionary state of that star to be determined.
A star’s life begins with the gravitational collapse of a gaseous nebula of material composed primarily of hydrogen, along with helium and trace amounts of heavier elements. When the stellar core is sufficiently dense, hydrogen becomes steadily converted into helium through nuclear fusion, releasing energy in the process. The remainder of the star’s interior carries energy away from the core through a combination of radiative and convective heat transfer processes. The star’s internal pressure prevents it from collapsing further under its own gravity. A star with mass greater than 0.4 times the Sun’s will expand to become a red giant when the hydrogen fuel in its core is exhausted. In some cases, it will fuse heavier elements at the core or in shells around the core. As the star expands it throws a part of its mass, enriched with those heavier elements, into the interstellar environment, to be recycled later as new stars. Meanwhile, the core becomes a stellar remnant: a white dwarf, a neutron star, or if it is sufficiently massive a black hole.
Binary and multi-star systems consist of two or more stars that are gravitationally bound and generally move around each other in stable orbits. When two such stars have a relatively close orbit, their gravitational interaction can have a significant impact on their evolution. Stars can form part of a much larger gravitationally bound structure, such as a star cluster or a galaxy. — Wikipedia
Stars (Eric Weisstein’s World of Astronomy, Wolfram Research)
David Darling’s Internet Encyclopedia of Science
Encyclopædia Britannica
Introduction
Guide to Stars & Galaxies (Telescope.org)
Search
Science
Stellar Astronomy is the study of stars and stellar evolution, and it is fundamental to our understanding of the Universe. The astrophysics of stars has been determined through observation and theoretical understanding; and from computer simulations of the interior. Star formation occurs in dense regions of dust and gas, known as giant molecular clouds. When destabilized, cloud fragments can collapse under the influence of gravity, to form a protostar. A sufficiently dense, and hot, core region will trigger nuclear fusion, thus creating a main-sequence star. — Wikipedia
Preservation
History
History of Stars (Universe Today)
Quotation
Library
WorldCat, Library of Congress, UPenn Online Books, Open Library
Participation
Education
Stars & Star Clusters (Ask an Astronomer, Cornell University)
Stars (Cosmos4Kids)
Course
Crash Course Astronomy (YouTube)
OER Commons: Open Educational Resources
Community
News
Science Daily, Phys.org, NPR Archives
Book
Government
Document
Expression
Fun
Poem
OEDILF: The Omnificent English Dictionary In Limerick Form
Music
More…
Stars News -- ScienceDaily News about Stars. Read science articles and see images on the birth of monstrous stars, brown dwarfs and red giants. Consider stellar evolution and more.
-
Shining light on sleeping cataclysmic binaries
on March 25, 2020 at 12:20 am
Almost 35 years ago, scientists made the then-radical proposal that colossal hydrogen bombs called novae go through a very long-term life cycle after erupting, fading to obscurity for hundreds of thousands of years and then building up to become full-fledged novae once more. A new study confirms that the novae we observe flashing throughout the universe represent just a few percent of these cataclysmic variables, as they are known, with the rest ''hiding'' in hibernation.
-
Star formation project maps nearby interstellar...
on March 23, 2020 at 2:13 pm
Astronomers have captured new, detailed maps of three nearby interstellar gas clouds containing regions of ongoing high-mass star formation. The results of this survey, called the Star Formation Project, will help improve our understanding of the star formation process.
-
The strange orbits of 'Tatooine' planetary disks
on March 19, 2020 at 2:32 pm
Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have found striking orbital geometries in protoplanetary disks around binary stars. While disks orbiting the most compact binary star systems share very nearly the same plane, disks encircling wide binaries have orbital planes that are severely tilted. These systems can teach us about planet formation in complex environments.
-
New telescope design could capture distant...
on March 18, 2020 at 6:37 pm
Researchers have designed a new camera that could allow hypertelescopes to image multiple stars at once. The enhanced telescope design holds the potential to obtain extremely high-resolution images of objects outside our solar system, such as planets, pulsars, globular clusters and distant galaxies.
-
On the origin of massive stars
on March 18, 2020 at 2:44 pm
A scene of stellar creation, captured by the NASA/ESA Hubble Space Telescope, sits near the outskirts of the famous Tarantula Nebula. This cloud of gas and dust, as well as the many young and massive stars surrounding it, is the perfect laboratory to study the origin of massive stars.
Phys.org - latest science and technology news stories Phys.org internet news portal provides the latest news on science including: Physics, Nanotechnology, Life Sciences, Space Science, Earth Science, Environment, Health and Medicine.
-
Unravelling the mystery of black holes:...
on March 31, 2020 at 7:59 am
Today, team COMPAS (Compact Object Mergers: Population Astrophysics and Statistics) has announced the first public beta release of their rapid binary population synthesis code (available for download here).
-
Astronomers observe high-redshift quasar PSO...
on March 30, 2020 at 1:00 pm
Using the Subaru telescope, astronomers from Taiwan have conducted spectroscopic observations of a high-redshift quasar designated PSO J006.1240+39.2219. Results of these observations, presented in a paper published March 19 on the arXiv pre-print server, provide more insights into the nature of this object.
-
Free-floating stars in the Milky Way's bulge
on March 30, 2020 at 11:25 am
The path of a light beam is bent by the presence of mass, as explained by General Relativity. A massive body can therefore act like a lens—a so called "gravitational lens"—to distort the image of an object seen behind it. Microlensing is a related phenomenon: a short flash of light is produced when a moving cosmic body, acting as a gravitational lens, modulates the intensity of light from a background star as it fortuitously passes in front of it. About fifty years ago scientists […]
-
Supermassive black holes shortly after the Big...
on March 23, 2020 at 4:16 pm
They are billions of times larger than our Sun: how is it possible that, as recently observed, supermassive black holes were already present when the Universe, now 14 billion years old, was "just" 800 million years old? For astrophysicists, the formation of these cosmic monsters in such a short time is a real scientific headache, which raises important questions on the current knowledge of the development of these celestial bodies.
-
The strange orbits of 'Tatooine' planetary disks
on March 19, 2020 at 2:46 pm
Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have found striking orbital geometries in protoplanetary disks around binary stars. While disks orbiting the most compact binary star systems share very nearly the same plane, disks encircling wide binaries have orbital planes that are severely tilted. These systems can teach us about planet formation in complex environments.