Stellar Evolution
... These stars are located very close to where the Hayashi limit intersects the Main Sequence. As you look at more massive stars, convection is found only in layers near the surface. By the time you get to stars that have masses similar to that of the Sun, the mass fraction that is involved in convect ...
... These stars are located very close to where the Hayashi limit intersects the Main Sequence. As you look at more massive stars, convection is found only in layers near the surface. By the time you get to stars that have masses similar to that of the Sun, the mass fraction that is involved in convect ...
Accretion Processes of Binaries of White Dwarfs
... • Higher harmonics are observed in the optical region • Zeeman effect can be used to derive the strength of B field. ...
... • Higher harmonics are observed in the optical region • Zeeman effect can be used to derive the strength of B field. ...
neutron star - Chabot College
... • What are white dwarf supernovae (Type Ia) and why are they good for measuring gigantic distances? • A white dwarf supernova arises from the explosion of an entire white dwarf triggered by carbon fusion when it gains enough mass to approach the 1.4 Msunlimit. The peak luminosity of the explosion ex ...
... • What are white dwarf supernovae (Type Ia) and why are they good for measuring gigantic distances? • A white dwarf supernova arises from the explosion of an entire white dwarf triggered by carbon fusion when it gains enough mass to approach the 1.4 Msunlimit. The peak luminosity of the explosion ex ...
Chapter 4 On the possibility of a helium white dwarf donor in the
... evolved donor star like in an ultracompact system the hydrogen can reside only in the outer layers that were lost being outside the Roche lobe. Juett et al. and Nelemans et al. suggest that spallation of accreted elements may be important (e.g., Bildsten, Salpeter & Wasserman 1992). However, it is n ...
... evolved donor star like in an ultracompact system the hydrogen can reside only in the outer layers that were lost being outside the Roche lobe. Juett et al. and Nelemans et al. suggest that spallation of accreted elements may be important (e.g., Bildsten, Salpeter & Wasserman 1992). However, it is n ...
What keeps stars shining? What holds them up? Lecture 14. The
... mechanism: if fusion rate increases slightly, heats core, causing star to expand and cool, which brings fusion rate down again. This is also why main sequence stars fall in a pretty small range of sizes. • Why aren't there any main sequence stars outside of the mass range 0.1 < M/M < 50 ? > 50 Msun ...
... mechanism: if fusion rate increases slightly, heats core, causing star to expand and cool, which brings fusion rate down again. This is also why main sequence stars fall in a pretty small range of sizes. • Why aren't there any main sequence stars outside of the mass range 0.1 < M/M < 50 ? > 50 Msun ...
Chapter 4 [PDF only] - Princeton University Press
... At the same time, hydrogen continues to burn in a shell surrounding the core. When helium ignition begins, the star moves quickly on the H-R diagram to the left side of the horizontal branch, and then evolves more slowly to the right along this branch, as seen in Fig. 4.1. Horizontal branch evolutio ...
... At the same time, hydrogen continues to burn in a shell surrounding the core. When helium ignition begins, the star moves quickly on the H-R diagram to the left side of the horizontal branch, and then evolves more slowly to the right along this branch, as seen in Fig. 4.1. Horizontal branch evolutio ...
Lecture 24: High Mass Star Formation Astro 6890/8980 Prof. Tom
... with a disk. Must overcome magnetic pressure, resulting in magnetospheric accretion for low mass stars. Must overcome photon pressure for high mass stars. ...
... with a disk. Must overcome magnetic pressure, resulting in magnetospheric accretion for low mass stars. Must overcome photon pressure for high mass stars. ...
the solar neighborhood. xxviii. the multiplicity fraction of nearby stars
... (epoch 2012.0), including main-sequence stars, white dwarfs, and L and T dwarfs, but excluding extrasolar planets. We note that because trigonometric parallaxes for nearby stars are constantly being updated, 17 objects in 13 systems originally included in our search are no longer members of the 10 p ...
... (epoch 2012.0), including main-sequence stars, white dwarfs, and L and T dwarfs, but excluding extrasolar planets. We note that because trigonometric parallaxes for nearby stars are constantly being updated, 17 objects in 13 systems originally included in our search are no longer members of the 10 p ...
–1– Solutions to PH6820 Midterm 1. Define the following: molecular
... 1. Define the following: molecular cloud, molecular core, protostar. Include typical properties when necessary. A molecular cloud is a distinct, self-gravitating cloud comprised primarily of H2 and He. The sizes range from 10 M⊙ (for a dark globule) to 106 M⊙ for the most massive giant molecular clo ...
... 1. Define the following: molecular cloud, molecular core, protostar. Include typical properties when necessary. A molecular cloud is a distinct, self-gravitating cloud comprised primarily of H2 and He. The sizes range from 10 M⊙ (for a dark globule) to 106 M⊙ for the most massive giant molecular clo ...
A radio pulsing white dwarf binary star
... but when in close orbits with less dense stars, white dwarfs can strip material from their companions, and the resulting mass transfer can generate atomic line2 and X-ray3 emission, as well as near- and mid-infrared radiation if the white dwarf is magnetic4 . However, even in binaries, white dwarfs ...
... but when in close orbits with less dense stars, white dwarfs can strip material from their companions, and the resulting mass transfer can generate atomic line2 and X-ray3 emission, as well as near- and mid-infrared radiation if the white dwarf is magnetic4 . However, even in binaries, white dwarfs ...
Lecture5
... (iii) Energy Transport: the manner in which energy produced in the central core is transported to the surface. (iiia) Conduction: energy carried by free electrons (e.g., metals). (iiib) Radiation: energy carried by photons (`random walk’ – takes long time from interior to surface). (iiic) Convectio ...
... (iii) Energy Transport: the manner in which energy produced in the central core is transported to the surface. (iiia) Conduction: energy carried by free electrons (e.g., metals). (iiib) Radiation: energy carried by photons (`random walk’ – takes long time from interior to surface). (iiic) Convectio ...
A new isolated dSph galaxy near the Local Group
... Apart from the two true isolated spheroidal dwarfs in the vicinity of our Local Group, the local volume within D < 10 Mpc contains one more known isolated dSph object, Apples I. That galaxy was found accidentally by Pasquali et al. (2005) on an image obtained with ACS HST. The radial velocity of App ...
... Apart from the two true isolated spheroidal dwarfs in the vicinity of our Local Group, the local volume within D < 10 Mpc contains one more known isolated dSph object, Apples I. That galaxy was found accidentally by Pasquali et al. (2005) on an image obtained with ACS HST. The radial velocity of App ...
Monitoring orbital period variations in eclipsing white dwarf binaries
... The Liverpool Telescope (LT) is a 2m fully robotic telescope on La Palma. RISE is a fast-readout camera with a single ‘V+R’ filter. Minimum exposure times are of the order of 1 second. To monitor short period variations we aim to observe one eclipse for each binary every 4-8 weeks, depending on the ...
... The Liverpool Telescope (LT) is a 2m fully robotic telescope on La Palma. RISE is a fast-readout camera with a single ‘V+R’ filter. Minimum exposure times are of the order of 1 second. To monitor short period variations we aim to observe one eclipse for each binary every 4-8 weeks, depending on the ...
Stellar Temperatures
... a) the atmospheric UV cutoff (for U) b) the sensitivity of old photographic plates (for B) c) the sensitivity of the human eye and 1P21 PMT (for V) d) the sensitivity of S20 PMT (for R) Advantage: Historical system, so lots of data available Wide passes, so useful for faint objects Disadvantage: His ...
... a) the atmospheric UV cutoff (for U) b) the sensitivity of old photographic plates (for B) c) the sensitivity of the human eye and 1P21 PMT (for V) d) the sensitivity of S20 PMT (for R) Advantage: Historical system, so lots of data available Wide passes, so useful for faint objects Disadvantage: His ...
The Life Cycles of Stars
... extreme release of stellar material and heat) to occur in its future. In truth, the only type of star that can undertake such an explosion is a high-mass star, a star with a greater solar mass than that of our sun. In astronomy, the higher a star is in mass, the more times it will go into a period o ...
... extreme release of stellar material and heat) to occur in its future. In truth, the only type of star that can undertake such an explosion is a high-mass star, a star with a greater solar mass than that of our sun. In astronomy, the higher a star is in mass, the more times it will go into a period o ...
A radio-pulsing white dwarf binary star
... M star’s spectral type (M5) suggests that its mass lies at the lower end of the allowed range for M2 . Assuming that the M star is close to its Roche lobe, its brightness leads to a distance estimate d = (M2 /0.3 M )1/3 (116 ± 16) pc. The amplitude spectra of the pulsations show the presence of tw ...
... M star’s spectral type (M5) suggests that its mass lies at the lower end of the allowed range for M2 . Assuming that the M star is close to its Roche lobe, its brightness leads to a distance estimate d = (M2 /0.3 M )1/3 (116 ± 16) pc. The amplitude spectra of the pulsations show the presence of tw ...
Stellar Population Modeling of Galaxies in Nearby Groups
... galaxies were studied in details from deep images, which were obtained with large ground-based telescopes and the Hubble Space Telescope (see, for example, Holtzman et al. (2000), Han et al. (1997), Da Costa et al.(1996), Martinez-Delgado and Aparicio (1998), Monkiewicz et al. (1999)). However, ther ...
... galaxies were studied in details from deep images, which were obtained with large ground-based telescopes and the Hubble Space Telescope (see, for example, Holtzman et al. (2000), Han et al. (1997), Da Costa et al.(1996), Martinez-Delgado and Aparicio (1998), Monkiewicz et al. (1999)). However, ther ...
Document
... Final collapse of burned-out stars Electron degeneracy pressure can hold up a star of mass 1.4M or less against its weight, and do so indefinitely. Stellar cores in this mass range at death become white dwarfs. For heavier stars: gravity overwhelms electron degeneracy pressure, and the collapse do ...
... Final collapse of burned-out stars Electron degeneracy pressure can hold up a star of mass 1.4M or less against its weight, and do so indefinitely. Stellar cores in this mass range at death become white dwarfs. For heavier stars: gravity overwhelms electron degeneracy pressure, and the collapse do ...
Binary Stars/Star Clusters
... (1) find a point source of X-rays (2) look for a star orbiting an unseen companion (3) determine mass of the unseen companion MPP©2004 ...
... (1) find a point source of X-rays (2) look for a star orbiting an unseen companion (3) determine mass of the unseen companion MPP©2004 ...
ph507lecnote07
... This energy can provide the fuel which allows the endothermic fusion reactions to create very high mass elements such as Uranium. The supernovae are responsible for all the elements with masses larger than iron found on Earth. ...
... This energy can provide the fuel which allows the endothermic fusion reactions to create very high mass elements such as Uranium. The supernovae are responsible for all the elements with masses larger than iron found on Earth. ...
Lecture20
... Newer stars have 1% - 4% heavier elements Old stars have 1/10 to 1/100 as many heavier elements as the Sun ...
... Newer stars have 1% - 4% heavier elements Old stars have 1/10 to 1/100 as many heavier elements as the Sun ...
Review for Astronomy 3 Midterm #2
... companion, and eventually will have enough hydrogen on its surface for that hydrogen to begin to fuse to helium. It will do this very quickly and then explode and be thrown from the white dwarf. Nova can be periodic, which means they can occur over and over again on the same star. Type I Supernova ...
... companion, and eventually will have enough hydrogen on its surface for that hydrogen to begin to fuse to helium. It will do this very quickly and then explode and be thrown from the white dwarf. Nova can be periodic, which means they can occur over and over again on the same star. Type I Supernova ...
Main-sequence stage Stellar lifetimes
... – Low-mass stars: the RR Lyrae variables are white horizontalbranch stars – Type II Cepheids are also low-mass stars. ...
... – Low-mass stars: the RR Lyrae variables are white horizontalbranch stars – Type II Cepheids are also low-mass stars. ...
PowerPoint 프레젠테이션
... If this limit holds, neutron star cannot be formed from the beginning (e.g. SN1987A; 108 Eddington Limit). ...
... If this limit holds, neutron star cannot be formed from the beginning (e.g. SN1987A; 108 Eddington Limit). ...
Line of Sight Column Densities of Polars Student: Scott Swindell
... the observational data currently available on Polars. In order to do this, we will model the stream at different phases and inclinations to see how and when it will eclipse the hot spot on the white dwarf. In order to model this a combination of Fortran and Interactive Data Language (IDL) will be u ...
... the observational data currently available on Polars. In order to do this, we will model the stream at different phases and inclinations to see how and when it will eclipse the hot spot on the white dwarf. In order to model this a combination of Fortran and Interactive Data Language (IDL) will be u ...