Origin of close binary systems
... 2) Studies of star forming regions & young clusters allow us to observe binary parameter distributions give extra info on massive star formation provide I.C. for models of interacting binary evol 3) We all need to learn more about binary evolution! ...
... 2) Studies of star forming regions & young clusters allow us to observe binary parameter distributions give extra info on massive star formation provide I.C. for models of interacting binary evol 3) We all need to learn more about binary evolution! ...
22. The Milky Way Galaxy
... Not enough radiating matter at large R to explain rotation curve => "dark" matter! Dark matter must be about 90% of the mass! Composition unknown. Probably mostly exotic particles that don't interact with ordinary matter at all (except gravity). Some may be brown dwarfs, cold white dwarfs … Most li ...
... Not enough radiating matter at large R to explain rotation curve => "dark" matter! Dark matter must be about 90% of the mass! Composition unknown. Probably mostly exotic particles that don't interact with ordinary matter at all (except gravity). Some may be brown dwarfs, cold white dwarfs … Most li ...
September 2013 - astronomy for beginners
... shows when night begins and the top line when night time ends with the inner black lines showing the beginning and end of twilight. The white areas show when the Moon is in the sky or black and blue when it is not. The areas where the Moon is shown black indicate that the sky is completely dark. See ...
... shows when night begins and the top line when night time ends with the inner black lines showing the beginning and end of twilight. The white areas show when the Moon is in the sky or black and blue when it is not. The areas where the Moon is shown black indicate that the sky is completely dark. See ...
PowerPoint
... High-mass star forming regions are much more distant (in average) than those of low-mass stars (high-mass: 3-7kpc vs. low-mass: 0.1-0.3 kpc) OB stars - form preferentially in the centre of dense star clusters - seem to live pref. in (tight) binary and higher order systems ...
... High-mass star forming regions are much more distant (in average) than those of low-mass stars (high-mass: 3-7kpc vs. low-mass: 0.1-0.3 kpc) OB stars - form preferentially in the centre of dense star clusters - seem to live pref. in (tight) binary and higher order systems ...
Chapter 12: Stellar Evolution - Otto
... Death of a low mass star • For solar mass star, core temperature not high enough for C fusion • Outer layers drift away into space • Core contracts, heats up • UV radiation ionizes surrounding gas • Stage 12 - A planetary nebula • (nothing to do with planets) ...
... Death of a low mass star • For solar mass star, core temperature not high enough for C fusion • Outer layers drift away into space • Core contracts, heats up • UV radiation ionizes surrounding gas • Stage 12 - A planetary nebula • (nothing to do with planets) ...
Chapter21
... In most other introductory astronomy textbooks, binary stars are covered in a piecemeal fashion in several different chapters. There are several reasons why I decided to cover binary stars in a single coherent chapter. First, most stars are in binary or multiple systems, so it isn’t reasonable to tr ...
... In most other introductory astronomy textbooks, binary stars are covered in a piecemeal fashion in several different chapters. There are several reasons why I decided to cover binary stars in a single coherent chapter. First, most stars are in binary or multiple systems, so it isn’t reasonable to tr ...
- IRSF: Past and Future
... Gamma-ray binaries are a subclass of X-ray binaries that emit the majority of the energy in the gamma-ray band. They are comprised of a compact object and a massive (>10 Msun) star with a circumstellar disk or strong stellar wind. Their emission, ranging from radio to TeV gamma-rays, show variations ...
... Gamma-ray binaries are a subclass of X-ray binaries that emit the majority of the energy in the gamma-ray band. They are comprised of a compact object and a massive (>10 Msun) star with a circumstellar disk or strong stellar wind. Their emission, ranging from radio to TeV gamma-rays, show variations ...
X-ray Astronomy and the search for Black Holes
... • Above about E~2 keV, there is a highly absorbed, hard component. – There is a clear detection of Fe K complex, indicating thin thermal origin – A single kT (~5 keV) fit would work – But the effective bandpass was narrow (E~2-10 keV) so only weak constraints can be placed on models – Reminescent of ...
... • Above about E~2 keV, there is a highly absorbed, hard component. – There is a clear detection of Fe K complex, indicating thin thermal origin – A single kT (~5 keV) fit would work – But the effective bandpass was narrow (E~2-10 keV) so only weak constraints can be placed on models – Reminescent of ...
Astronomy Assignment #1
... as determined from the table in the text’s appendix. Thus, Alpha Centauri A is slightly larger than the Sun with a diameter of 1.23 solar diameters. Alpha Centauri B is (60/85) = 0.706 times smaller than Alpha Centauri A. based on the ratio of their angular sizes (and the fact that they are at the s ...
... as determined from the table in the text’s appendix. Thus, Alpha Centauri A is slightly larger than the Sun with a diameter of 1.23 solar diameters. Alpha Centauri B is (60/85) = 0.706 times smaller than Alpha Centauri A. based on the ratio of their angular sizes (and the fact that they are at the s ...
SN 2004dj
... Garnett et al. (1997) measured the metallity and its radial distribution in NGC 2403 ...
... Garnett et al. (1997) measured the metallity and its radial distribution in NGC 2403 ...
Coronal Mass Ejections and Angular Momentum Loss in Young Stars
... We have shown that for young, solar-type stars, spin down due to CMEs might play a significant role in stellar rotation evolution after the star has ceased accreting. Our Figs. 1 and 2 illustrate a critical selection effect in performing this kind of calculation: we only have data for the most activ ...
... We have shown that for young, solar-type stars, spin down due to CMEs might play a significant role in stellar rotation evolution after the star has ceased accreting. Our Figs. 1 and 2 illustrate a critical selection effect in performing this kind of calculation: we only have data for the most activ ...
GenGeoAstroII_Stars
... Question: What determines the velocity with which the sun is moving around the Galactic centre? ...
... Question: What determines the velocity with which the sun is moving around the Galactic centre? ...
Life Cycle of stars
... dwarf stars usually have temperatures near absolute zero, and have diameters similar to that of terrestrial planets such as Earth and Venus. In this stage, the black dwarf star will remain forever emitting no light. That is the end of the low mass medium sized stars. When stars formed with a large m ...
... dwarf stars usually have temperatures near absolute zero, and have diameters similar to that of terrestrial planets such as Earth and Venus. In this stage, the black dwarf star will remain forever emitting no light. That is the end of the low mass medium sized stars. When stars formed with a large m ...
X-ray heating of the chromosphere
... c) There are significant differences in height in the chromosphere between the layers where the core of H line profile is formed and the layers where deposited energy reach the maximum. In such a case the intensities of central parts of H line profiles should not be close related with the rates of ...
... c) There are significant differences in height in the chromosphere between the layers where the core of H line profile is formed and the layers where deposited energy reach the maximum. In such a case the intensities of central parts of H line profiles should not be close related with the rates of ...
Rotational spin-up in the 30-Myr
... shown in Fig.2, the latter cluster lacks rotational period measurements for solar-mass stars (those shown in Fig.1 are for 0.6-0.9 M stars), and has too few measurements at lower masses down to 0.3 M to allow a robust derivation of the mass-dependent rotational distribution at this age (Irwin et a ...
... shown in Fig.2, the latter cluster lacks rotational period measurements for solar-mass stars (those shown in Fig.1 are for 0.6-0.9 M stars), and has too few measurements at lower masses down to 0.3 M to allow a robust derivation of the mass-dependent rotational distribution at this age (Irwin et a ...
File
... *Spin rapidly—perhaps 100 to 1,000 rotations per second *Be hot—with surface temperatures of millions of degrees K ...
... *Spin rapidly—perhaps 100 to 1,000 rotations per second *Be hot—with surface temperatures of millions of degrees K ...
Talk
... WDMS for which repeat SDSS spectroscopic observations are available. - From the SDSS spectra we determine Sp of the companions, Teff, M, log(g) of the WDs, as well as distance estimates to the systems. Even though some of the stellar parameters obtained from our decomposing/fitting technique differ ...
... WDMS for which repeat SDSS spectroscopic observations are available. - From the SDSS spectra we determine Sp of the companions, Teff, M, log(g) of the WDs, as well as distance estimates to the systems. Even though some of the stellar parameters obtained from our decomposing/fitting technique differ ...
The Origin of the Milky Way
... The Milky Way is a spiral galaxy The Galaxy is shaped like a disk The Sun is located at the inner edge of a spiral arm about 2/3 of the way out from the center to the edge The main components of the Galaxy are the disk, the bulge, and the halo We can measure the mass of the Galaxy from the orbi ...
... The Milky Way is a spiral galaxy The Galaxy is shaped like a disk The Sun is located at the inner edge of a spiral arm about 2/3 of the way out from the center to the edge The main components of the Galaxy are the disk, the bulge, and the halo We can measure the mass of the Galaxy from the orbi ...
The most important questions to study for the exam
... 6. A star appears to move back and forth with a period of exactly 1 year with respect to a distant galaxy that appears close to it in our sky. What is the most likely cause of this observed motion? • The observed motion is simply the motion of the star around the center of the galaxy. ...
... 6. A star appears to move back and forth with a period of exactly 1 year with respect to a distant galaxy that appears close to it in our sky. What is the most likely cause of this observed motion? • The observed motion is simply the motion of the star around the center of the galaxy. ...
Binary evolution in a nutshell
... Here we made the assumption that the fraction of the stellar mass available for hydrogen fusion is the same for all stars. In reality, this factor will vary; it is ∼ 0.15 for the Sun, but may be much larger for more massive stars, for example because they have convective cores and can mix material f ...
... Here we made the assumption that the fraction of the stellar mass available for hydrogen fusion is the same for all stars. In reality, this factor will vary; it is ∼ 0.15 for the Sun, but may be much larger for more massive stars, for example because they have convective cores and can mix material f ...
MSci Astrophysics 210PHY412 - Queen's University Belfast
... Evidence for stellar winds: “P-Cygni” lines in hot stars - resonance transitions in optical or UV ...
... Evidence for stellar winds: “P-Cygni” lines in hot stars - resonance transitions in optical or UV ...
L11
... Evidence for stellar winds: “P-Cygni” lines in hot stars - resonance transitions in optical or UV ...
... Evidence for stellar winds: “P-Cygni” lines in hot stars - resonance transitions in optical or UV ...
Earth in Space - Learning Outcomes
... When the Apollo 11 satellite took the first men to the Moon in 1969 its trajectory was very closely monitored. The satellite had a velocity of 5374 m s-1 when 26306 km from the centre of the Earth and this had dropped to 3560 m s-1 when it was 54368 km from the centre of the Earth. The rocket motors ...
... When the Apollo 11 satellite took the first men to the Moon in 1969 its trajectory was very closely monitored. The satellite had a velocity of 5374 m s-1 when 26306 km from the centre of the Earth and this had dropped to 3560 m s-1 when it was 54368 km from the centre of the Earth. The rocket motors ...
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.