www-thphys.physics.ox.ac.uk
... Major problems: “blending” & intrinsic stellar variability ¿LMC=1£10-7 (Alcock+00, Bennett 05); 1.5£10-8 (EROS: Jetzer 04) Given blending, best interpreted as upper limits <20% of ¿ expected if DM stellar; excludes masses down to 10-7M¯ ¿ possibly compatible with known stars (Evans & Belokurov) ...
... Major problems: “blending” & intrinsic stellar variability ¿LMC=1£10-7 (Alcock+00, Bennett 05); 1.5£10-8 (EROS: Jetzer 04) Given blending, best interpreted as upper limits <20% of ¿ expected if DM stellar; excludes masses down to 10-7M¯ ¿ possibly compatible with known stars (Evans & Belokurov) ...
Evolution of a Low-Mass Star
... planets.) Shine due to ionizing radiation from the hot core of the star embedded in a cool gas cloud. - Carbon core called a “White Dwarf” - shines only by stored heat, no more nuclear reactions. About the size of Earth. Cools to become black dwarf, remaining about the size of Earth. ...
... planets.) Shine due to ionizing radiation from the hot core of the star embedded in a cool gas cloud. - Carbon core called a “White Dwarf” - shines only by stored heat, no more nuclear reactions. About the size of Earth. Cools to become black dwarf, remaining about the size of Earth. ...
Astronomy 103 – Midterm 2 – October 29, 2014
... 24. Once the luminosity of a star is known, what has to be measured in order to find the star’s radius? a) parallax angle to find distance b) color to find distance c) color to find surface temperature d) parallax angle to find surface temperature ...
... 24. Once the luminosity of a star is known, what has to be measured in order to find the star’s radius? a) parallax angle to find distance b) color to find distance c) color to find surface temperature d) parallax angle to find surface temperature ...
SHELL H II REGIONS IN NGC 6334
... The Next Frontiers in Star Formation • With the availability of the SMA and the future construction of other interferometers we will start to study star formation with new frontiers: • Binary and multiple star formation • Star formation in the extremes (very massive stars and brown dwarfs) • Starbu ...
... The Next Frontiers in Star Formation • With the availability of the SMA and the future construction of other interferometers we will start to study star formation with new frontiers: • Binary and multiple star formation • Star formation in the extremes (very massive stars and brown dwarfs) • Starbu ...
Centimeter and Millimeter Observations of Very Young Binary Systems
... The Next Frontiers in Star Formation • With the availability of the SMA and the future construction of other interferometers we will start to study star formation with new frontiers: • Binary and multiple star formation • Star formation in the extremes (very massive stars and brown dwarfs) • Starbu ...
... The Next Frontiers in Star Formation • With the availability of the SMA and the future construction of other interferometers we will start to study star formation with new frontiers: • Binary and multiple star formation • Star formation in the extremes (very massive stars and brown dwarfs) • Starbu ...
Constellations
... Most atlases of today have their origins with those that were derived from Hipparchus and used his “magnitude” system. ...
... Most atlases of today have their origins with those that were derived from Hipparchus and used his “magnitude” system. ...
the spectrum of a partially ionized jet sodium ionization in t
... low-luminosity, pre-main-sequence stars. Line profiles for the Nal doublet at 5990,5986 Aare discussed and compared with the observations for those T Tauri stars with P-Cygni profiles. We find that the observed shape of the lines put significative constraints on the rate of mass-loss (M > 3 x 10~ 8 ...
... low-luminosity, pre-main-sequence stars. Line profiles for the Nal doublet at 5990,5986 Aare discussed and compared with the observations for those T Tauri stars with P-Cygni profiles. We find that the observed shape of the lines put significative constraints on the rate of mass-loss (M > 3 x 10~ 8 ...
Answers to Coursebook questions – Chapter E2
... A white dwarf star is an end stage in the evolution of a star. It is very hot, small in size and of small luminosity. It differs from a main sequence star of the same temperature mainly in the mass, and luminosity and radius, all of which are very much smaller. ...
... A white dwarf star is an end stage in the evolution of a star. It is very hot, small in size and of small luminosity. It differs from a main sequence star of the same temperature mainly in the mass, and luminosity and radius, all of which are very much smaller. ...
Properties of Stars
... run out of fuel and collapse due to gravity. Death of Low-Mass Stars • Stars less than one-half the mass of the sun never evolve to the red giant stage but remain in the stable main-sequence stage until they consume all their hydrogen fuel and collapse into a white dwarf. ...
... run out of fuel and collapse due to gravity. Death of Low-Mass Stars • Stars less than one-half the mass of the sun never evolve to the red giant stage but remain in the stable main-sequence stage until they consume all their hydrogen fuel and collapse into a white dwarf. ...
Life Cycle of a Star
... A dying red super giant star can suddenly explode. The explosion is called a supernova. After the star explodes, some of the materials from the star are left behind. This material may form a neutron star. Neutron stars are the remains of high-mass stars. The most massive stars become black holes whe ...
... A dying red super giant star can suddenly explode. The explosion is called a supernova. After the star explodes, some of the materials from the star are left behind. This material may form a neutron star. Neutron stars are the remains of high-mass stars. The most massive stars become black holes whe ...
Black Holes - WhatsOutThere
... singularity. At the Singularity itself the gravity is so strong it crushes the space time out of existence. Depending on the singularities mass, at a certain distance you will need the speed of light to escape. This distance is the black holes horizon which is its surface any thing that goes though ...
... singularity. At the Singularity itself the gravity is so strong it crushes the space time out of existence. Depending on the singularities mass, at a certain distance you will need the speed of light to escape. This distance is the black holes horizon which is its surface any thing that goes though ...
The Life of a Star
... Death: The outer layers falling inward rebound off of the dense iron core and explode outward in an explosion known as a Supernova, leaving either a Neutron Star or a Black Hole behind. ...
... Death: The outer layers falling inward rebound off of the dense iron core and explode outward in an explosion known as a Supernova, leaving either a Neutron Star or a Black Hole behind. ...
Life Cycle of a Star - Intervention Worksheet
... A dying red super giant star can suddenly explode. The explosion is called a supernova. After the star explodes, some of the materials from the star are left behind. This material may form a neutron star. Neutron stars are the remains of high-mass stars. The most massive stars become black holes whe ...
... A dying red super giant star can suddenly explode. The explosion is called a supernova. After the star explodes, some of the materials from the star are left behind. This material may form a neutron star. Neutron stars are the remains of high-mass stars. The most massive stars become black holes whe ...
Stars Life Cycle WS
... A dying red super giant star can suddenly explode. The explosion is called a supernova. After the star explodes, some of the materials from the star are left behind. This material may form a neutron star. Neutron stars are the remains of high-mass stars. The most massive stars become black holes whe ...
... A dying red super giant star can suddenly explode. The explosion is called a supernova. After the star explodes, some of the materials from the star are left behind. This material may form a neutron star. Neutron stars are the remains of high-mass stars. The most massive stars become black holes whe ...
Slide 1
... The mass loss rates for OB (and WR) stars are currently in question at the order-of-magnitude level ( see Fig 1 ) with profound implications for stellar evolution, mass loss processes across the HR diagram and the injection of enriched gas into the ISM. The recognition of clumped and/or porous radia ...
... The mass loss rates for OB (and WR) stars are currently in question at the order-of-magnitude level ( see Fig 1 ) with profound implications for stellar evolution, mass loss processes across the HR diagram and the injection of enriched gas into the ISM. The recognition of clumped and/or porous radia ...
Pre-Main Sequence Evolution
... The Milky Way has several thousand of these objects, each with masses of 104 M8< M < 107 M8, and sizes between 10 and 100 pc. Although the average density of these clouds is ~ 100 cm-3, these objects are very clumpy, with large numbers of colder, dense cores. Orion is the one of the nearest (but n ...
... The Milky Way has several thousand of these objects, each with masses of 104 M8< M < 107 M8, and sizes between 10 and 100 pc. Although the average density of these clouds is ~ 100 cm-3, these objects are very clumpy, with large numbers of colder, dense cores. Orion is the one of the nearest (but n ...
Linking Asteroids and Meteorites through Reflectance Spectroscopy
... of energy since the rest of the star collapses and then bounces off the neutron core • 1044-46 Joules • Annual energy generation of Sun is 1034 Joules ...
... of energy since the rest of the star collapses and then bounces off the neutron core • 1044-46 Joules • Annual energy generation of Sun is 1034 Joules ...
Gravity simplest fusion
... • When a neutron star forms, the pull of gravity is so great that it overrides the electron degeneracy pressure of the atoms of the star. • The electrons are forced into their respective nuclei, where they combine with protons to form neutrons. This greatly decreases the size of each atom, and allow ...
... • When a neutron star forms, the pull of gravity is so great that it overrides the electron degeneracy pressure of the atoms of the star. • The electrons are forced into their respective nuclei, where they combine with protons to form neutrons. This greatly decreases the size of each atom, and allow ...
Integrative Studies 410 Our Place in the Universe
... years (much longer than all other stages combined) – Temperature ~ 15 million K at core, 6000 K at surface – Size ~ Sun ...
... years (much longer than all other stages combined) – Temperature ~ 15 million K at core, 6000 K at surface – Size ~ Sun ...
1 The Gravitational Field Gravitational Potential Energy Grav
... Escape Speed, General The Earth’s result can be extended to any planet ...
... Escape Speed, General The Earth’s result can be extended to any planet ...
Chapter 12. Basic Equations of Stellar Structure
... mass into energy and gain the power needed to keep themselves shining for billions of years. It took another 35 years before physicists worked out the details of this process, namely the p-p reactions that turn Hydrogen into Helium, releasing energy in the process. Now we understand a star as basica ...
... mass into energy and gain the power needed to keep themselves shining for billions of years. It took another 35 years before physicists worked out the details of this process, namely the p-p reactions that turn Hydrogen into Helium, releasing energy in the process. Now we understand a star as basica ...
Milky Way thin disk
... Originally it was thought that our Galaxy had an R1/4 bulge We now know that it’s possible to model all the luminosity of the central regions by a bar Since bars are dynamical states of a disk, we do not need a separate stellar population for the bulge; the bar is part of the inner disk Many galacti ...
... Originally it was thought that our Galaxy had an R1/4 bulge We now know that it’s possible to model all the luminosity of the central regions by a bar Since bars are dynamical states of a disk, we do not need a separate stellar population for the bulge; the bar is part of the inner disk Many galacti ...
Final Exam: Chs 4-5, 12-17
... d. Less massive protostars reach the main sequence in a shorter time than more massive protostars. ____ 49. Electron degeneracy occurs when a. solar wind particles become trapped in the Earth's magnetic field. b. thermonuclear reactions halt the contraction of a protostar. c. magnetic fields inhibit ...
... d. Less massive protostars reach the main sequence in a shorter time than more massive protostars. ____ 49. Electron degeneracy occurs when a. solar wind particles become trapped in the Earth's magnetic field. b. thermonuclear reactions halt the contraction of a protostar. c. magnetic fields inhibit ...
Cygnus X-1
Cygnus X-1 (abbreviated Cyg X-1) is a well-known galactic X-ray source, thought to be a black hole, in the constellation Cygnus. It was discovered in 1964 during a rocket flight and is one of the strongest X-ray sources seen from Earth, producing a peak X-ray flux density of 6977229999999999999♠2.3×10−23 Wm−2 Hz−1 (7003230000000000000♠2.3×103 Jansky). Cygnus X-1 was the first X-ray source widely accepted to be a black hole and it remains among the most studied astronomical objects in its class. The compact object is now estimated to have a mass about 14.8 times the mass of the Sun and has been shown to be too small to be any known kind of normal star, or other likely object besides a black hole. If so, the radius of its event horizon is about 7004440000000000000♠44 km.Cygnus X-1 belongs to a high-mass X-ray binary system about 7019574266339685654♠6070 ly from the Sun that includes a blue supergiant variable star designated HDE 226868 which it orbits at about 0.2 AU, or 20% of the distance from the Earth to the Sun. A stellar wind from the star provides material for an accretion disk around the X-ray source. Matter in the inner disk is heated to millions of degrees, generating the observed X-rays. A pair of jets, arranged perpendicular to the disk, are carrying part of the energy of the infalling material away into interstellar space.This system may belong to a stellar association called Cygnus OB3, which would mean that Cygnus X-1 is about five million years old and formed from a progenitor star that had more than 7001400000000000000♠40 solar masses. The majority of the star's mass was shed, most likely as a stellar wind. If this star had then exploded as a supernova, the resulting force would most likely have ejected the remnant from the system. Hence the star may have instead collapsed directly into a black hole.Cygnus X-1 was the subject of a friendly scientific wager between physicists Stephen Hawking and Kip Thorne in 1975, with Hawking betting that it was not a black hole. He conceded the bet in 1990 after observational data had strengthened the case that there was indeed a black hole in the system. This hypothesis has not been confirmed due to a lack of direct observation but has generally been accepted from indirect evidence.