Pathways to Habitability: from disks to active stars, planets and life
... Planets formed in the gas disk gain large atmospheres made of hydrogen ...
... Planets formed in the gas disk gain large atmospheres made of hydrogen ...
Stars
... Alpha Centauri Our nearest neighbor is actually a trinary (triple) star system consisting of two medium size stars orbiting closely around each other and a third, distant red dwarf orbiting the middle two. This red dwarf, called Proxima Centauri, is actually our nearest neighbor currently. It has a ...
... Alpha Centauri Our nearest neighbor is actually a trinary (triple) star system consisting of two medium size stars orbiting closely around each other and a third, distant red dwarf orbiting the middle two. This red dwarf, called Proxima Centauri, is actually our nearest neighbor currently. It has a ...
Exam Study Guide
... 90. In a survey of pulsars in binary systems, it is found that none of the pulsars has a mass greater than 3 solar masses. This is because … 91. If the Sun were replaced by a 1-solar-mass black hole, how would the Earth be affected? 92. A massive star becomes a supernova when it … 93. Nuclear fusion ...
... 90. In a survey of pulsars in binary systems, it is found that none of the pulsars has a mass greater than 3 solar masses. This is because … 91. If the Sun were replaced by a 1-solar-mass black hole, how would the Earth be affected? 92. A massive star becomes a supernova when it … 93. Nuclear fusion ...
Stars - Trimble County Schools
... Constellation stars • Astronomers use constellations to locate particular stars • Stars within a constellation are named according to apparent magnitude – Brightest star is labeled alpha – Next brightest beta and so on ...
... Constellation stars • Astronomers use constellations to locate particular stars • Stars within a constellation are named according to apparent magnitude – Brightest star is labeled alpha – Next brightest beta and so on ...
At the Heart of the Matter: The Blue White Dwarf in M 57. Paul Temple
... DO He rich objects with temperatures in excess of 45,000K. The spectrum is dominated by the signature of HeII, although H and higher elements may be observed in smaller amounts. DB This class may be regarded as an extension of the DO group into lower temperature regions (below around 30,000K). The c ...
... DO He rich objects with temperatures in excess of 45,000K. The spectrum is dominated by the signature of HeII, although H and higher elements may be observed in smaller amounts. DB This class may be regarded as an extension of the DO group into lower temperature regions (below around 30,000K). The c ...
Islip Invitational 2013 Astronomy Examination Student
... empty place is left, into which new matter from other clouds falls, creating more stars. c. When massive stars form, their UV radiation and later their final explosions compress the gas in the cloud and cause a new group of stars to form. d. When giant molecular clouds collide with each other, they ...
... empty place is left, into which new matter from other clouds falls, creating more stars. c. When massive stars form, their UV radiation and later their final explosions compress the gas in the cloud and cause a new group of stars to form. d. When giant molecular clouds collide with each other, they ...
Friday, April 11
... form a helium nucleus, plus some byproducts (actually, a total of 6 nuclei are involved) Mass of products is less than the original mass The missing mass is emitted in the form of energy, according to Einstein’s famous formulas: ...
... form a helium nucleus, plus some byproducts (actually, a total of 6 nuclei are involved) Mass of products is less than the original mass The missing mass is emitted in the form of energy, according to Einstein’s famous formulas: ...
The Properties of Stars
... The luminosity of a star is the total electromagnetic energy it emits in a unit of time. Two stars can have the same luminosity and very different apparent magnitudes. Alpha Centauri A and the Sun, for example, are both spectral class G2 stars and have about the same luminosity L = 3.86×1026 W. On t ...
... The luminosity of a star is the total electromagnetic energy it emits in a unit of time. Two stars can have the same luminosity and very different apparent magnitudes. Alpha Centauri A and the Sun, for example, are both spectral class G2 stars and have about the same luminosity L = 3.86×1026 W. On t ...
Gravitational potential energy
... Notation: =0 means solar abundance. [ ] denotes logarithmic ratio. At very early times, [Fe/H]=negative (e.g. =-1.5) since the heavy elements have not be created yet, Type II Supernovae occur at earlier times. They produce both O and Fe and so [O/Fe] is zero. At later times, Type I Supernovae make m ...
... Notation: =0 means solar abundance. [ ] denotes logarithmic ratio. At very early times, [Fe/H]=negative (e.g. =-1.5) since the heavy elements have not be created yet, Type II Supernovae occur at earlier times. They produce both O and Fe and so [O/Fe] is zero. At later times, Type I Supernovae make m ...
Constellations & Stars - Toms River Regional Schools :: Home
... attracts nearby gases so a ball forms. • Nuclear fusion occurs & Helium is formed from Hydrogen • A new star is born in our galaxy every 18 days ...
... attracts nearby gases so a ball forms. • Nuclear fusion occurs & Helium is formed from Hydrogen • A new star is born in our galaxy every 18 days ...
Chapter 18 Notes - Valdosta State University
... As the material in the nebula begins to accrete, the temperature begins to increase and a protostar is formed. This process continues until fusion begins and at this point the star is born and takes its place on the main sequence depending on its temperature and brightness. When the hydrogen is use ...
... As the material in the nebula begins to accrete, the temperature begins to increase and a protostar is formed. This process continues until fusion begins and at this point the star is born and takes its place on the main sequence depending on its temperature and brightness. When the hydrogen is use ...
Astronomy 100, Fall 2006 Name: Due: November 28, 2006 at 11 a.m.
... University and his research team found a gamma ray burst — an eruption of gamma rays a billion times greater than the Sun but lasting only a few milliseconds, originating in areas of space that do not seem to have Milky Way stars — and were able to photograph the “afterglow” of the phenomenon. ...
... University and his research team found a gamma ray burst — an eruption of gamma rays a billion times greater than the Sun but lasting only a few milliseconds, originating in areas of space that do not seem to have Milky Way stars — and were able to photograph the “afterglow” of the phenomenon. ...
Chapter 27 Stars and Galaxies
... Stars with a low apparent mag. and higher absolute mag. appear brighter than if they were 32.6 ly away – Like the Sun ...
... Stars with a low apparent mag. and higher absolute mag. appear brighter than if they were 32.6 ly away – Like the Sun ...
Stellar evolution
Stellar evolution is the process by which a star changes during its lifetime. Depending on the mass of the star, this lifetime ranges from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are born from collapsing clouds of gas and dust, often called nebulae or molecular clouds. Over the course of millions of years, these protostars settle down into a state of equilibrium, becoming what is known as a main-sequence star.Nuclear fusion powers a star for most of its life. Initially the energy is generated by the fusion of hydrogen atoms at the core of the main-sequence star. Later, as the preponderance of atoms at the core becomes helium, stars like the Sun begin to fuse hydrogen along a spherical shell surrounding the core. This process causes the star to gradually grow in size, passing through the subgiant stage until it reaches the red giant phase. Stars with at least half the mass of the Sun can also begin to generate energy through the fusion of helium at their core, whereas more-massive stars can fuse heavier elements along a series of concentric shells. Once a star like the Sun has exhausted its nuclear fuel, its core collapses into a dense white dwarf and the outer layers are expelled as a planetary nebula. Stars with around ten or more times the mass of the Sun can explode in a supernova as their inert iron cores collapse into an extremely dense neutron star or black hole. Although the universe is not old enough for any of the smallest red dwarfs to have reached the end of their lives, stellar models suggest they will slowly become brighter and hotter before running out of hydrogen fuel and becoming low-mass white dwarfs.Stellar evolution is not studied by observing the life of a single star, as most stellar changes occur too slowly to be detected, even over many centuries. Instead, astrophysicists come to understand how stars evolve by observing numerous stars at various points in their lifetime, and by simulating stellar structure using computer models.In June 2015, astronomers reported evidence for Population III stars in the Cosmos Redshift 7 galaxy at z = 6.60. Such stars are likely to have existed in the very early universe (i.e., at high redshift), and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life as we know it.