SOME CONSTRAINTS ON GALAXY EVOLUTION IMPOSED BY
... The suggestion that the high S values, which are currently observed in most giant ellipticals, is due to cluster formation during collisions and subsequent mergers of giant spiral galaxies meets with four possible difficulties: (1) The luminosity function of the numerous clusters produced by the rec ...
... The suggestion that the high S values, which are currently observed in most giant ellipticals, is due to cluster formation during collisions and subsequent mergers of giant spiral galaxies meets with four possible difficulties: (1) The luminosity function of the numerous clusters produced by the rec ...
CONSTRAINING THE EVOLUTION OF ZZ CETI A. S. Mukadam
... There are two competing internal evolutionary processes that govern the change in pulsation period with time (Ṗ ) for a single mode in the theoretical models of the ZZ Ceti stars. Cooling of the star increases the periods as a result of the increasing degeneracy, and residual gravitational contract ...
... There are two competing internal evolutionary processes that govern the change in pulsation period with time (Ṗ ) for a single mode in the theoretical models of the ZZ Ceti stars. Cooling of the star increases the periods as a result of the increasing degeneracy, and residual gravitational contract ...
Beasts of the Southern Wild: Discovery of nine Ultra Faint satellites
... but could be approximately estimated from the source number counts in g, r, i filters. These number counts peak at magnitudes 23.7, 23.6, 22.9 in g, r, i correspondingly, indicating that the catalogues start to be significantly affected by incompleteness at somewhat brigher magnitudes g∼23.5, r∼23.4 ...
... but could be approximately estimated from the source number counts in g, r, i filters. These number counts peak at magnitudes 23.7, 23.6, 22.9 in g, r, i correspondingly, indicating that the catalogues start to be significantly affected by incompleteness at somewhat brigher magnitudes g∼23.5, r∼23.4 ...
Population synthesis for symbiotic stars with white dwarf accretors
... In this paper, binaries are considered as SySs if they satisfy the following conditions: (i) The systems are detached; (ii) The luminosity of the hot component is larger than 10L⊙ which is the “threshold” luminosity for the hot component of SySs as inferred by Mikolajewska & Kenyon (1992), Mürset e ...
... In this paper, binaries are considered as SySs if they satisfy the following conditions: (i) The systems are detached; (ii) The luminosity of the hot component is larger than 10L⊙ which is the “threshold” luminosity for the hot component of SySs as inferred by Mikolajewska & Kenyon (1992), Mürset e ...
Lecture Notes
... another, given the numbers of stars with magnitudes 5 and 7. He concluded that such close pairs are real binaries. Herschel observed α Geminorum, also known as Castor, between November 1779 and March 1803. The less luminous of the two stars was to the North, and preceding visual (i.e. with smaller r ...
... another, given the numbers of stars with magnitudes 5 and 7. He concluded that such close pairs are real binaries. Herschel observed α Geminorum, also known as Castor, between November 1779 and March 1803. The less luminous of the two stars was to the North, and preceding visual (i.e. with smaller r ...
Substellar Objects in Nearby Young Clusters (SONYC) VI: The
... upon our extensive previous work, we present spectra for 12 of the faintest candidates from our deep multi-band imaging, plus seven random objects in the same fields, using MOIRCS on Subaru. We confirm seven new sources as young very low mass objects (VLMOs), with Teff of 2400–3100 K and mid-M to ea ...
... upon our extensive previous work, we present spectra for 12 of the faintest candidates from our deep multi-band imaging, plus seven random objects in the same fields, using MOIRCS on Subaru. We confirm seven new sources as young very low mass objects (VLMOs), with Teff of 2400–3100 K and mid-M to ea ...
Binary progenitor models of type IIb supernovae
... evolution code. We identify the limited range of initial orbital periods and mass ratios required to produce type IIb binary progenitors. The rate we predict from our standard models, which assume conservative mass transfer, is about six times smaller than the current rate indicated by observations. ...
... evolution code. We identify the limited range of initial orbital periods and mass ratios required to produce type IIb binary progenitors. The rate we predict from our standard models, which assume conservative mass transfer, is about six times smaller than the current rate indicated by observations. ...
The incidence of stellar mergers and mass gainers among massive
... combined brightness of the main-sequence components exceeds 104 L⊙ . A binary system containing two mainsequence stars is counted only once. The simulations started with 70% binaries and 30% single stars at birth. For the case of continuous star formation we find that the contribution of pre interac ...
... combined brightness of the main-sequence components exceeds 104 L⊙ . A binary system containing two mainsequence stars is counted only once. The simulations started with 70% binaries and 30% single stars at birth. For the case of continuous star formation we find that the contribution of pre interac ...
Investigating Black Hole Kicks
... stars, the so called binary (or multiple) stellar systems. Stellar binary systems in which the mutual separation is much larger than the stellar radii can be approximated as systems of two point masses M1 and M2 , interacting via gravitational force. Let’s call r1 , r2 , RCM the position of the bodi ...
... stars, the so called binary (or multiple) stellar systems. Stellar binary systems in which the mutual separation is much larger than the stellar radii can be approximated as systems of two point masses M1 and M2 , interacting via gravitational force. Let’s call r1 , r2 , RCM the position of the bodi ...
Super and massive AGB stars-IV. Final fates
... The white dwarf/gravitational collapse supernova boundary is also important from a galactic chemical evolution perspective due both to the substantial difference in nucleosynthetic products from intermediate-mass compared to massive stars (e.g Romano et al. 2010; Kobayashi et al. 2011), and to the d ...
... The white dwarf/gravitational collapse supernova boundary is also important from a galactic chemical evolution perspective due both to the substantial difference in nucleosynthetic products from intermediate-mass compared to massive stars (e.g Romano et al. 2010; Kobayashi et al. 2011), and to the d ...
Gamma-Ray Line Emission from Radioactive Isotopes in Stars and
... and difficulties. We discuss their nature briefly, addressing a few of the physical aspects involved. The treatment of convection, and its implications, constitute one problem area common to several source types. The convective coupling between mass zones in both the oxygen-neon and hydrogen shell-b ...
... and difficulties. We discuss their nature briefly, addressing a few of the physical aspects involved. The treatment of convection, and its implications, constitute one problem area common to several source types. The convective coupling between mass zones in both the oxygen-neon and hydrogen shell-b ...
Phase-resolved high-resolution spectrophotometry of the eclipsing
... of light with the hot accretion plasma on the white dwarf emitting cyclotron radiation (steep ingress/egress) and the accretion stream (shallow ingress/egress). Both emitters radiate anisotropically which gives the explanation for the different stepsizes at ingress and egress. The eclipse of the whi ...
... of light with the hot accretion plasma on the white dwarf emitting cyclotron radiation (steep ingress/egress) and the accretion stream (shallow ingress/egress). Both emitters radiate anisotropically which gives the explanation for the different stepsizes at ingress and egress. The eclipse of the whi ...
Galaxy Evolution
... collapse, and explode • Type Ia – Carbonoxygen white dwarfs that exceed the white dwarf mass limit ...
... collapse, and explode • Type Ia – Carbonoxygen white dwarfs that exceed the white dwarf mass limit ...
A propelling neutron star in the enigmatic Be-star γ Cassiopeia
... the rate ṀB πρv0 RB2 could gravitationally sustain a luminosity GM ṀB /R0 ∼ 0.1ṀB c2 (where c is the speed of light). Hence, if all gravitationally captured matter were able to reach the NS surface, a bright X-ray source would appear. However, for matter to reach the NS surface, it should penet ...
... the rate ṀB πρv0 RB2 could gravitationally sustain a luminosity GM ṀB /R0 ∼ 0.1ṀB c2 (where c is the speed of light). Hence, if all gravitationally captured matter were able to reach the NS surface, a bright X-ray source would appear. However, for matter to reach the NS surface, it should penet ...
The Dynamics of White Dwarfs, Black Holes and Stellar Cusps
... In chapter 4 it is shown that close binary supermassive black holes (SMBHs) should produce a burst of tidal disruptions of up to 0.1 yr−1 as they form. The quiescent rate is ∼ 10−5 yr−1 per galaxy, and it is therefore shown that binary SMBHs can potentially be identified via multiple tidal disruptio ...
... In chapter 4 it is shown that close binary supermassive black holes (SMBHs) should produce a burst of tidal disruptions of up to 0.1 yr−1 as they form. The quiescent rate is ∼ 10−5 yr−1 per galaxy, and it is therefore shown that binary SMBHs can potentially be identified via multiple tidal disruptio ...
Collisions and close encounters involving massive main
... (2002) have studied encounters between low-mass main-sequence stars and, with the exception of Benz & Hills (1987), found that mixing was minimal. It is important to determine if this is also the case in encounters involving high-mass stars, since the merger may deliver fresh hydrogen to the core of ...
... (2002) have studied encounters between low-mass main-sequence stars and, with the exception of Benz & Hills (1987), found that mixing was minimal. It is important to determine if this is also the case in encounters involving high-mass stars, since the merger may deliver fresh hydrogen to the core of ...
The Stellar Initial Mass Function and Beyond
... massive forming stars together with the effects of interactions and mergers in dense forming stellar systems. The mass of the most massive star that forms in a cluster is observed to increase systematically with the mass of the cluster, and the most massive clusters may form stars that are massive e ...
... massive forming stars together with the effects of interactions and mergers in dense forming stellar systems. The mass of the most massive star that forms in a cluster is observed to increase systematically with the mass of the cluster, and the most massive clusters may form stars that are massive e ...
Elliptical galaxies
... Many of the normal ellipticals contain visible amounts of dust, partially manifested as a dust disk. The metallicity of ellipticals and S0 galaxies increases towards the galaxy center, as derived from color gradients. Also in S0 galaxies the bulge appears redder than the ...
... Many of the normal ellipticals contain visible amounts of dust, partially manifested as a dust disk. The metallicity of ellipticals and S0 galaxies increases towards the galaxy center, as derived from color gradients. Also in S0 galaxies the bulge appears redder than the ...
Formation of millisecond pulsars with CO white dwarf companions–I
... better understand the mechanisms of the electron capture and core collapse supernovae, knowledge of the distribution of birth masses of neutron stars is vital. However, in order to weigh a neutron star it must be a member of a binary system. This introduces an uncertainty in determining the original ...
... better understand the mechanisms of the electron capture and core collapse supernovae, knowledge of the distribution of birth masses of neutron stars is vital. However, in order to weigh a neutron star it must be a member of a binary system. This introduces an uncertainty in determining the original ...
Discovery of a Dwarf Poststarburst Galaxy near a High Column
... extrapolate this result to conclude that all high equivalent width Ly absorbers (NH i 1014.5 cm2) can be identified as the very extended halos of galaxies, although most would be too faint to be detectable at the distance of the Key Project absorbers. On the other hand, investigations of the dis ...
... extrapolate this result to conclude that all high equivalent width Ly absorbers (NH i 1014.5 cm2) can be identified as the very extended halos of galaxies, although most would be too faint to be detectable at the distance of the Key Project absorbers. On the other hand, investigations of the dis ...
Astronomy Astrophysics A VLT/FLAMES survey for massive binaries in Westerlund 1 &
... Methods. To accomplish this we have utilised our spectroscopic data in conjunction with multi-year optical and near-IR photometric observations in order to search for binary signatures. Comparison of these data to synthetic non-LTE model atmosphere spectra were used to derive the fundamental propert ...
... Methods. To accomplish this we have utilised our spectroscopic data in conjunction with multi-year optical and near-IR photometric observations in order to search for binary signatures. Comparison of these data to synthetic non-LTE model atmosphere spectra were used to derive the fundamental propert ...
White dwarfs, black holes and neutron stars in close binaries
... and forms a sphere which in its centre has a temperature and pressure high enough to start hydrogen fusion. The star remains in this phase for most of its active life and only in the last ten percent of its active life its conditions change dramatically. Then the hydrogen fuel in its centre is exhau ...
... and forms a sphere which in its centre has a temperature and pressure high enough to start hydrogen fusion. The star remains in this phase for most of its active life and only in the last ten percent of its active life its conditions change dramatically. Then the hydrogen fuel in its centre is exhau ...
Chapter 6 in the LSST Science Book
... In addition to interacting gravitationally with each other, both Clouds are in the gravitational proximity of the Galaxy. Until recently, it was held that the Clouds are captive satellites of the Galaxy and have made several passages through the Galaxy disk. The extended stream of HI, called the Mag ...
... In addition to interacting gravitationally with each other, both Clouds are in the gravitational proximity of the Galaxy. Until recently, it was held that the Clouds are captive satellites of the Galaxy and have made several passages through the Galaxy disk. The extended stream of HI, called the Mag ...
A Detailed Spectroscopic and Photometric Analysis of DQ White
... Strong molecular absorption bands that appear to originate from some carbon compound have also been reported in several cool white dwarfs (see, e.g. Schmidt et al. 1995; Harris et al. 2003). The detailed model atmosphere and photometric analysis by BRL of some of these objects reveals that in additi ...
... Strong molecular absorption bands that appear to originate from some carbon compound have also been reported in several cool white dwarfs (see, e.g. Schmidt et al. 1995; Harris et al. 2003). The detailed model atmosphere and photometric analysis by BRL of some of these objects reveals that in additi ...
They might be giants: luminosity class, planet frequency, and planet
... stars for which the signal of a transiting planet is largest, and exclude sub-giant and giant stars. Brown et al. (2011) used D51 (Mg Ib line) photometry and Sloan gD51 color to exclude giants, however this is also sensitive to temperature and metallicity and is not available for all targets. The KI ...
... stars for which the signal of a transiting planet is largest, and exclude sub-giant and giant stars. Brown et al. (2011) used D51 (Mg Ib line) photometry and Sloan gD51 color to exclude giants, however this is also sensitive to temperature and metallicity and is not available for all targets. The KI ...