Grosdidier et al. 1998
... Bulges host supermassive black holes. Formation process still unknown. Related to bulge formation? (Gebhardt et al., Ferrarese et al., Ghez et al.). Metal rich halos are widespread: M31 (Durrell 1994, Rich 1996) other galaxies (Mouhcine et al. 2005). ~15 hot Jupiter transit planets discovered using ...
... Bulges host supermassive black holes. Formation process still unknown. Related to bulge formation? (Gebhardt et al., Ferrarese et al., Ghez et al.). Metal rich halos are widespread: M31 (Durrell 1994, Rich 1996) other galaxies (Mouhcine et al. 2005). ~15 hot Jupiter transit planets discovered using ...
The Circumstellar Environments of Young Stars at AU Scales
... emission (Millan-Gabet et al., 1999). The measured size was unexpectedly large in the context of then-current disk models of HAeBe objects (e.g., Hillenbrand et al., 1992), which predicted NIR diameter of 0.2 AU based on optically thick, geometrically thin circumstellar disks with a small dust-free ...
... emission (Millan-Gabet et al., 1999). The measured size was unexpectedly large in the context of then-current disk models of HAeBe objects (e.g., Hillenbrand et al., 1992), which predicted NIR diameter of 0.2 AU based on optically thick, geometrically thin circumstellar disks with a small dust-free ...
The white dwarf population within 40 pc of the Sun
... evolution of white dwarfs is determined by a simple gravothermal process. However, although the basic picture of white dwarf evolution has remained unchanged for some time, we now have very reliable and accurate evolutionary tracks, which take into account all the relevant physical processes involve ...
... evolution of white dwarfs is determined by a simple gravothermal process. However, although the basic picture of white dwarf evolution has remained unchanged for some time, we now have very reliable and accurate evolutionary tracks, which take into account all the relevant physical processes involve ...
Microlensing Events by Proxima Centauri in 2014 and 2016
... 0.145 R⊙ ± 0.011 R⊙ (Ségransan et al. 2003). But, as an effectively isolated star, Proxima’s mass can only be estimated from mass-luminosity (M-L) relations as ∼0.12 M⊙ . A star’s mass is its most important physical parameter, being the primary determinant of its temperature, radius, luminosity, li ...
... 0.145 R⊙ ± 0.011 R⊙ (Ségransan et al. 2003). But, as an effectively isolated star, Proxima’s mass can only be estimated from mass-luminosity (M-L) relations as ∼0.12 M⊙ . A star’s mass is its most important physical parameter, being the primary determinant of its temperature, radius, luminosity, li ...
Formation of low-mass helium white dwarfs
... thousands or even more stars. A nearby supernova, collisions with another gas cloud, or the pressure wave of a galaxy’s spiral arms passing through the region can disrupt the balance between the cloud’s gravity and the outward gas pressure of the molecules, causing the cloud to collapse. As the clou ...
... thousands or even more stars. A nearby supernova, collisions with another gas cloud, or the pressure wave of a galaxy’s spiral arms passing through the region can disrupt the balance between the cloud’s gravity and the outward gas pressure of the molecules, causing the cloud to collapse. As the clou ...
Course Materials - Weber State University
... passes straight through it. Hold up your hand in the square of light, parallel to the card. Now move your hand so that the light strikes it at an angle, as shown in the two figures at right. 2. When you hold your card parallel to your hand, does the square of light cover more or less of your skin th ...
... passes straight through it. Hold up your hand in the square of light, parallel to the card. Now move your hand so that the light strikes it at an angle, as shown in the two figures at right. 2. When you hold your card parallel to your hand, does the square of light cover more or less of your skin th ...
Stationary Population III accretion discs
... of order 3. The details of this calculation are given in Appendix A. The optical depth still containing the surface density can be fully expressed in terms of density and temperature using the angular momentum equation (1). 4 O PAC I T Y Primordial matter as an unprocessed relict from the big bang s ...
... of order 3. The details of this calculation are given in Appendix A. The optical depth still containing the surface density can be fully expressed in terms of density and temperature using the angular momentum equation (1). 4 O PAC I T Y Primordial matter as an unprocessed relict from the big bang s ...
0004-637X 778 2 119
... disk mass, Md , some of the model sources begin their evolution in the accretion phase, some of them enter the accretion phase at a later epoch, and others possibly never accrete over their entire lifetimes. The sources that cannot accrete are likely to be active radio pulsars as long as they remain ...
... disk mass, Md , some of the model sources begin their evolution in the accretion phase, some of them enter the accretion phase at a later epoch, and others possibly never accrete over their entire lifetimes. The sources that cannot accrete are likely to be active radio pulsars as long as they remain ...
Models of the Structure and Evolution of Protoplanetary Disks
... 2)/q. This steep slope arises because most of the stellar radiation is absorbed and reemitted at small radii where the disk is hot. This produces strong emission at short wavelength. The long wavelength flux is weak because only little stellar radiation is absorbed at large radii. Observations of CT ...
... 2)/q. This steep slope arises because most of the stellar radiation is absorbed and reemitted at small radii where the disk is hot. This produces strong emission at short wavelength. The long wavelength flux is weak because only little stellar radiation is absorbed at large radii. Observations of CT ...
Magnetars: properties, origin and evolution
... powerful short bursts which often reach super-Eddington luminosities. More rarely, they also emit intermediate and giant flares, the latter involving the release of up to about 1046 erg in less than half a second. Magnetars also show pulsed X-ray emission with typical luminosity of ∼ 1035 erg s−1 in ...
... powerful short bursts which often reach super-Eddington luminosities. More rarely, they also emit intermediate and giant flares, the latter involving the release of up to about 1046 erg in less than half a second. Magnetars also show pulsed X-ray emission with typical luminosity of ∼ 1035 erg s−1 in ...
ROTATION CURVES OF HIGH-LUMINOSITY SPIRAL GALAXIES
... neighboring spiral galaxies. Until recently, this comparison was ham pered by very incomplete observations of rotation curves of external galaxies. Optical observations generally determined velocities only across the nucleus and inner regions; velocities at large nuclear dis tances were rarely obt ...
... neighboring spiral galaxies. Until recently, this comparison was ham pered by very incomplete observations of rotation curves of external galaxies. Optical observations generally determined velocities only across the nucleus and inner regions; velocities at large nuclear dis tances were rarely obt ...
Ch a n d
... various kinds of mass outflow. The impact of plasma onto the stellar surface from magnetospheric accretion streams, can be a dominant source of energy and momentum in the upper atmospheres of T Tauri stars. We present models in which turbulence is induced by these impacts, and waves then spread out ...
... various kinds of mass outflow. The impact of plasma onto the stellar surface from magnetospheric accretion streams, can be a dominant source of energy and momentum in the upper atmospheres of T Tauri stars. We present models in which turbulence is induced by these impacts, and waves then spread out ...
radiation and matter interaction in strong magnetic field of accreting
... of magnitude. As a result NSs permit us to study experimentally those areas of physics which have been attainable only by theoreticians. Emission that bears the imprint of “radiation-matter” interaction is generated by accretion of matter onto a compact object – one of the most powerful energy relea ...
... of magnitude. As a result NSs permit us to study experimentally those areas of physics which have been attainable only by theoreticians. Emission that bears the imprint of “radiation-matter” interaction is generated by accretion of matter onto a compact object – one of the most powerful energy relea ...
Lyman Break Galaxies at z~ 5: Luminosity Function
... luminosities and from emission lines in rest-frame optical band are up to several tens of M⊙ yr−1 (e.g., Steidel et al. 1996b; Pettini et al. 2001). Their stellar population has been investigated by comparing the optical to near-infrared spectral energy distributions (SEDs) with stellar population s ...
... luminosities and from emission lines in rest-frame optical band are up to several tens of M⊙ yr−1 (e.g., Steidel et al. 1996b; Pettini et al. 2001). Their stellar population has been investigated by comparing the optical to near-infrared spectral energy distributions (SEDs) with stellar population s ...
Star formation
Star formation is the process by which dense regions within molecular clouds in interstellar space, sometimes referred to as ""stellar nurseries"" or ""star-forming regions"", collapse to form stars. As a branch of astronomy, star formation includes the study of the interstellar medium (ISM) and giant molecular clouds (GMC) as precursors to the star formation process, and the study of protostars and young stellar objects as its immediate products. It is closely related to planet formation, another branch of astronomy. Star formation theory, as well as accounting for the formation of a single star, must also account for the statistics of binary stars and the initial mass function.In June 2015, astronomers reported evidence for Population III stars in the Cosmos Redshift 7 galaxy at z = 6.60. Such stars are likely to have existed in the very early universe (i.e., at high redshift), and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life as we know it.