Learning Objectives
... easily calculated. However, some special types of variable and exploding stars do have known, standard luminosities. Consequently, if you can identify a star as being one of these special types, you know its luminosity. Then you only have to measure its brightness to be able to compute its distance. ...
... easily calculated. However, some special types of variable and exploding stars do have known, standard luminosities. Consequently, if you can identify a star as being one of these special types, you know its luminosity. Then you only have to measure its brightness to be able to compute its distance. ...
Search for Life in the Universe
... harsh conditions Search for evidence of microbes • Controversial Martian microbes ...
... harsh conditions Search for evidence of microbes • Controversial Martian microbes ...
Test 3 Review Clicker Questions
... What is probably responsible for the increase in temperature of the corona far from the Sun’s surface? ...
... What is probably responsible for the increase in temperature of the corona far from the Sun’s surface? ...
The Evolution of Elements and Isotopes
... numerous theoretical possibilities. Major insights come add up to the observed composition. In both processes, from recent advances in astronomy, which are beginning seed nuclei capture neutrons until unstable isotopes form. to revolutionize our understanding of chemical evolution. These isotopes th ...
... numerous theoretical possibilities. Major insights come add up to the observed composition. In both processes, from recent advances in astronomy, which are beginning seed nuclei capture neutrons until unstable isotopes form. to revolutionize our understanding of chemical evolution. These isotopes th ...
5. cosmic distance ladder ii: standard candles
... easily calculated. However, some special types of variable and exploding stars do have known, standard luminosities. Consequently, if you can identify a star as being one of these special types, you know its luminosity. Then you only have to measure its brightness to be able to compute its distance. ...
... easily calculated. However, some special types of variable and exploding stars do have known, standard luminosities. Consequently, if you can identify a star as being one of these special types, you know its luminosity. Then you only have to measure its brightness to be able to compute its distance. ...
ASTR 1020 Homework Solutions Chapter 1
... years and a is in AU. (a) P = 64 years, so P2 = 4096. Then a = cube root of 4096 = 16 AU. (b) The distance between perihelion and aphelion equals the major-axis, i.e., two times the semi-major axis or 2a. So, if the comet is 31.5 AU from the Sun at aphelion, then it must be (2 × 16 AU) – 31.5 AU = 0 ...
... years and a is in AU. (a) P = 64 years, so P2 = 4096. Then a = cube root of 4096 = 16 AU. (b) The distance between perihelion and aphelion equals the major-axis, i.e., two times the semi-major axis or 2a. So, if the comet is 31.5 AU from the Sun at aphelion, then it must be (2 × 16 AU) – 31.5 AU = 0 ...
The Universe and Galactic Formation
... CO and H2 are the most common molecules in interstellar gas clouds. The deep cold also causes the gas to clump to high densities. When the density reaches a certain point, stars form. ...
... CO and H2 are the most common molecules in interstellar gas clouds. The deep cold also causes the gas to clump to high densities. When the density reaches a certain point, stars form. ...
ASTRONOMY
... CO and H2 are the most common molecules in interstellar gas clouds. The deep cold also causes the gas to clump to high densities. When the density reaches a certain point, stars form. ...
... CO and H2 are the most common molecules in interstellar gas clouds. The deep cold also causes the gas to clump to high densities. When the density reaches a certain point, stars form. ...
Big Bear Valley Astronomical Society
... connected to Sirius as the constellation itself did not take on its current form until Roman times. Sirius is a hot white star that will shine brightly for a long time to come. It is also a known binary system, with a tiny white dwarf star, coloquially known as 'the Pup', circling the brighter prima ...
... connected to Sirius as the constellation itself did not take on its current form until Roman times. Sirius is a hot white star that will shine brightly for a long time to come. It is also a known binary system, with a tiny white dwarf star, coloquially known as 'the Pup', circling the brighter prima ...
BBC Stargazing Live Star and Moon Guide
... enough gravitational pull to be nearly spherical and clear its neighbourhood of debris. This 2006 definition resulted in Pluto being kicked out of the planetary club! The eight planets in our Solar System look like stars in the night sky, with five being bright enough to be seen with the naked eye. ...
... enough gravitational pull to be nearly spherical and clear its neighbourhood of debris. This 2006 definition resulted in Pluto being kicked out of the planetary club! The eight planets in our Solar System look like stars in the night sky, with five being bright enough to be seen with the naked eye. ...
JCMT Sciences on Debris Disks and other brief
... ● The 450µm data nicely help to constrain the SED and hence the dust grain size distribution ● 33% of the SONS sample have detected peaks at, or close to, the star at 450µm ...
... ● The 450µm data nicely help to constrain the SED and hence the dust grain size distribution ● 33% of the SONS sample have detected peaks at, or close to, the star at 450µm ...
OUTFLOW INFALL AND ROTATION IN HIGH
... On the other hand, if O protostars do not have disks, a physical explanation is required: • O-star disks “hidden” inside toroids • O-star disk lifetime too short, i.e. less than rotation period: photo-evaporation by O star (Hollenbach et al. ...
... On the other hand, if O protostars do not have disks, a physical explanation is required: • O-star disks “hidden” inside toroids • O-star disk lifetime too short, i.e. less than rotation period: photo-evaporation by O star (Hollenbach et al. ...
Chapter 4 Hydrostatic Equilibrium
... • Our observational mindset is often Eulerian: we tend to think of monitoring a river by placing a measuring device at a fixed point on the river rather than imagining a measuring device floating down the river with a given packet of water. • We tend to formulate microscopic laws of physics in a Lag ...
... • Our observational mindset is often Eulerian: we tend to think of monitoring a river by placing a measuring device at a fixed point on the river rather than imagining a measuring device floating down the river with a given packet of water. • We tend to formulate microscopic laws of physics in a Lag ...
Protostellar/PMS Mass Infall Luminosity Problem
... The infall rate of the secondary grows by 2–3 orders of magnitude at the approximate time of the periastro, becoming comparable to the infall rate of the primary. ...
... The infall rate of the secondary grows by 2–3 orders of magnitude at the approximate time of the periastro, becoming comparable to the infall rate of the primary. ...
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.