ppt
... feeding: binary companion star growth: accretor results from stellar evolution for AGN feeding: galaxy mergers? growth: accretion on to `seed’ black hole? Both problems better understood for binaries, so develop ideas and theory here first. ...
... feeding: binary companion star growth: accretor results from stellar evolution for AGN feeding: galaxy mergers? growth: accretion on to `seed’ black hole? Both problems better understood for binaries, so develop ideas and theory here first. ...
a new planet around an m dwarf: revealing a correlation between
... the star’s broadband colors and spectral type. Our adopted trigonometric parallax yields a distance of 9:17 1:7 pc and an absolute visual magnitude MV ¼ 12:2. For its B V color GJ 317 is unusually faint, lying 1.8 mag below the mean Hipparcos main sequence as defined by Wright (2004). Its locat ...
... the star’s broadband colors and spectral type. Our adopted trigonometric parallax yields a distance of 9:17 1:7 pc and an absolute visual magnitude MV ¼ 12:2. For its B V color GJ 317 is unusually faint, lying 1.8 mag below the mean Hipparcos main sequence as defined by Wright (2004). Its locat ...
Formation and Evolution of Binary Millisecond Pulsars with Helium
... thereby increasing the mass of the core. Eventually the hydrogen-rich envelope surrounding the helium core becomes so diffuse that it cannot be supported and the subsequent collapse leaves behind a detached (cooling) remnant in orbit with its spun-up NS companion. Since the properties of red giants ...
... thereby increasing the mass of the core. Eventually the hydrogen-rich envelope surrounding the helium core becomes so diffuse that it cannot be supported and the subsequent collapse leaves behind a detached (cooling) remnant in orbit with its spun-up NS companion. Since the properties of red giants ...
Measuring the Masses of Neutron Stars
... (or disrupted) double neutron star remains, like the Hulse-Taylor binary pulsar PSR 1913+16 (or a neutron star – white dwarf system, if the mass of the Be companion is less than 8 M A). In HMXBs with an orbital period less than about a year the compact object will enter the core of the OB companion ...
... (or disrupted) double neutron star remains, like the Hulse-Taylor binary pulsar PSR 1913+16 (or a neutron star – white dwarf system, if the mass of the Be companion is less than 8 M A). In HMXBs with an orbital period less than about a year the compact object will enter the core of the OB companion ...
Star Wreck
... respective minimal values beyond which they are unstable. This leads to an explosion. The lifetime of a contaminated star is determined by the parameters of the underlying supersymmetric theory and can be in the Gyr range. The energy released from the cataclysmic death of a neutron star may be the o ...
... respective minimal values beyond which they are unstable. This leads to an explosion. The lifetime of a contaminated star is determined by the parameters of the underlying supersymmetric theory and can be in the Gyr range. The energy released from the cataclysmic death of a neutron star may be the o ...
http://www.lanl.gov/orgs/adtsc/publications/science_highlights_2013/docs/Pg24_25.pdf
... upernovae are being observed in increasing numbers, with hundreds discovered each year by a wide array of survey telescopes [1]. Despite the large amounts of data, the information we can derive about the progenitor stars from all of these observations is limited because for most of these SNe we have ...
... upernovae are being observed in increasing numbers, with hundreds discovered each year by a wide array of survey telescopes [1]. Despite the large amounts of data, the information we can derive about the progenitor stars from all of these observations is limited because for most of these SNe we have ...
asteroseismological study of massive zz ceti stars with
... giving rise to an oxygen–neon or an oxygen–neon–magnesium core white dwarf star with stellar mass larger than ∼1.05 M (Ritossa et al. 1999; Siess 2007). Therefore, the massive component of the DA white dwarf mass distribution is populated by carbon–oxygen core stars, with a progenitor star of ∼3–7 ...
... giving rise to an oxygen–neon or an oxygen–neon–magnesium core white dwarf star with stellar mass larger than ∼1.05 M (Ritossa et al. 1999; Siess 2007). Therefore, the massive component of the DA white dwarf mass distribution is populated by carbon–oxygen core stars, with a progenitor star of ∼3–7 ...
Barium Stars: Theoretical Interpretation
... after a limited number of TPs. TDU ceases when the mass of the envelope decreases by mass loss down to ∼0.5 M . The TDU mass per pulse reaches a maximum after about ten thermal pulses and then decreases (Straniero et al. 2003). The major neutron source in AGB stars is the 13 C(α, n)16 O reaction, w ...
... after a limited number of TPs. TDU ceases when the mass of the envelope decreases by mass loss down to ∼0.5 M . The TDU mass per pulse reaches a maximum after about ten thermal pulses and then decreases (Straniero et al. 2003). The major neutron source in AGB stars is the 13 C(α, n)16 O reaction, w ...
Article PDF - IOPscience
... LBC contour maps of the old and young populations is presented in Figure 3. Stars belonging to the kinematically cold, more metal-rich population are represented by filled (open) star symbols when they are within 1 j (2 j) of the Ibata et al. (2006) radial velocity peak of this component (see the to ...
... LBC contour maps of the old and young populations is presented in Figure 3. Stars belonging to the kinematically cold, more metal-rich population are represented by filled (open) star symbols when they are within 1 j (2 j) of the Ibata et al. (2006) radial velocity peak of this component (see the to ...
Stellar death - Department of Astronomy
... Teaspoon of white dwarf stuff weighs as much as SUV! A114: Lecture 20—28 Mar 2007 ...
... Teaspoon of white dwarf stuff weighs as much as SUV! A114: Lecture 20—28 Mar 2007 ...
Chapter 7 Stellar models and stellar stability
... Stellar models and stellar stability In the previous chapters we have reviewed the most important physical processes taking place in stellar interiors, and we derived the differential equations that determine the structure and evolution of a star. By putting these ingredients together we can constru ...
... Stellar models and stellar stability In the previous chapters we have reviewed the most important physical processes taking place in stellar interiors, and we derived the differential equations that determine the structure and evolution of a star. By putting these ingredients together we can constru ...
Basics about stars
... • White dwarfs : Stars with ZAMS mass below 8M end as white dwarfs. Consisting of a Carbon Oxygen core electron degeneracy supports the star against the pull of gravity. The Chandrasekhar limit prohibits WD‘s more massive than 1.44M • Neutron stars : Stars with initially up to 25M end their life ...
... • White dwarfs : Stars with ZAMS mass below 8M end as white dwarfs. Consisting of a Carbon Oxygen core electron degeneracy supports the star against the pull of gravity. The Chandrasekhar limit prohibits WD‘s more massive than 1.44M • Neutron stars : Stars with initially up to 25M end their life ...
UMich w/s
... There is a well-established half-light size bi-modality all systems with size ~ < 30pc are purely stellar −16< Mv < 0 (!!) M/L ~ 3; e.g. UCDs, Hilker et al 07; Rejkuba et al 07 all systems with size greater than ~120pc have a dark-matter halo There are no known (virial equilibrium) galaxies with ...
... There is a well-established half-light size bi-modality all systems with size ~ < 30pc are purely stellar −16< Mv < 0 (!!) M/L ~ 3; e.g. UCDs, Hilker et al 07; Rejkuba et al 07 all systems with size greater than ~120pc have a dark-matter halo There are no known (virial equilibrium) galaxies with ...
Stellar models and stellar stability
... Such models are called polytropic models. The properties of polytropic stellar models were examined in the computer practicum, and are covered by Chapter 19 of K & W, sections 19.1–7 and 19.9. In the second approach we consider simple scaling relations between stellar models with dif ...
... Such models are called polytropic models. The properties of polytropic stellar models were examined in the computer practicum, and are covered by Chapter 19 of K & W, sections 19.1–7 and 19.9. In the second approach we consider simple scaling relations between stellar models with dif ...
Slide 1
... For a white dwarf with R~ 5x108 cm, M~Msun, and L ~ 6.25x1038 MeV/s 200 nm ≤ ν ≤ ~.1 Å This ranges from the UV to X-Rays! However the disk itself, because of a smaller L will emit at longer wavelengths. ...
... For a white dwarf with R~ 5x108 cm, M~Msun, and L ~ 6.25x1038 MeV/s 200 nm ≤ ν ≤ ~.1 Å This ranges from the UV to X-Rays! However the disk itself, because of a smaller L will emit at longer wavelengths. ...
gravitational collapse to black holes
... The PNS will cool, condense further, and after a while settle down to a colder (on nuclear scales) equilibrium star => a neutron star ...
... The PNS will cool, condense further, and after a while settle down to a colder (on nuclear scales) equilibrium star => a neutron star ...
Anna Frebel nucleosynthesis, stars + chemical evolution
... Previous ‘as observed’, raw MDF is not a realistic presentation! (but shows that we have been doing a good job in finding these stars..) ...
... Previous ‘as observed’, raw MDF is not a realistic presentation! (but shows that we have been doing a good job in finding these stars..) ...
A search for nearby counterparts to the moving objects in the Hubble
... two photographic surveys of proper motions, the Luyten Half Second Catalogue (1979, LHS) and the survey by Knox, Hawkins & Hambly (1999; hereafter KHH). We show that both surveys appear to have greater power to detect intrinsically faint high proper motion objects than the IRGS survey. In neither gr ...
... two photographic surveys of proper motions, the Luyten Half Second Catalogue (1979, LHS) and the survey by Knox, Hawkins & Hambly (1999; hereafter KHH). We show that both surveys appear to have greater power to detect intrinsically faint high proper motion objects than the IRGS survey. In neither gr ...
full text pdf
... R 5 4 8 in considerable detail, and the next two sections illustrate the considerable search through parameter space one must make in order to determine which models do not fit the observed periods, as well as those that do fit. We will not repeat this discussion, but rather describe by way of examp ...
... R 5 4 8 in considerable detail, and the next two sections illustrate the considerable search through parameter space one must make in order to determine which models do not fit the observed periods, as well as those that do fit. We will not repeat this discussion, but rather describe by way of examp ...
16.1 A Little History
... ble explanations, the most intriguing possibility is that stars more massive than ∼ 17M may collapse ‘quietly’ to form black holes and either very faint supernovae or no supernova at all. ...
... ble explanations, the most intriguing possibility is that stars more massive than ∼ 17M may collapse ‘quietly’ to form black holes and either very faint supernovae or no supernova at all. ...
The X-ray Bursters Problem and its Implications to the Equation of
... of the neutron star due to accreted material from a companion in a close binary system. When these objects are bright enough, the local X-ray luminosity in the atmosphere may approach the Eddington limit. In these cases, photospheric layers can be lifted o from the neutron star surface by radiation ...
... of the neutron star due to accreted material from a companion in a close binary system. When these objects are bright enough, the local X-ray luminosity in the atmosphere may approach the Eddington limit. In these cases, photospheric layers can be lifted o from the neutron star surface by radiation ...
A model of low-mass neutron stars with a quark core
... mass and radius, respectively). Also given here is the packing factor α. For all critical configurations, this quantity is positive and (except for configuration f ) of the same order of magnitude as for white dwarfs. Figure 2 shows a plot of matter density ρ against coordinate r (1) for configuration ...
... mass and radius, respectively). Also given here is the packing factor α. For all critical configurations, this quantity is positive and (except for configuration f ) of the same order of magnitude as for white dwarfs. Figure 2 shows a plot of matter density ρ against coordinate r (1) for configuration ...
Recycling strange stars to millisecond periods
... been found (Stergioulas et al. 1999; Zdunik et al. 2000; Zdunik & Gourgoulhon 2001). As shown in Zdunik et al. (2001, hereafter Paper I), a careful treatment of the crust of SS to some extent softens these conclusions, but important differences still remain. Recently, parameters of marginally stable ...
... been found (Stergioulas et al. 1999; Zdunik et al. 2000; Zdunik & Gourgoulhon 2001). As shown in Zdunik et al. (2001, hereafter Paper I), a careful treatment of the crust of SS to some extent softens these conclusions, but important differences still remain. Recently, parameters of marginally stable ...
the opportunities and challenges for astrometry in the 21st century
... all of the non-members from the sample. By measuring the relative proper motions of the stars in the field of the cluster we can identify stars not moving with the motion of the cluster using techniques described, for example, by Vasilevskis, Klemola, & Preston (1958) and Platais et al. (2003). In t ...
... all of the non-members from the sample. By measuring the relative proper motions of the stars in the field of the cluster we can identify stars not moving with the motion of the cluster using techniques described, for example, by Vasilevskis, Klemola, & Preston (1958) and Platais et al. (2003). In t ...
Astronomy 104: Stellar Astronomy
... •Blown out into interstellar medium to become part of gas that forms new generation of stars ...
... •Blown out into interstellar medium to become part of gas that forms new generation of stars ...