SGR 1900+14
... Emit typically brief (1-100 ms) bursts that may exceed Eddington Luminosities and very rarely, Giant Flares Rotate in a very narrow period interval (5-11 s) and slow down faster than any other object (~10-10-10-11 s/s) Are powered by magnetic field energy, which heats the neutron star interior so th ...
... Emit typically brief (1-100 ms) bursts that may exceed Eddington Luminosities and very rarely, Giant Flares Rotate in a very narrow period interval (5-11 s) and slow down faster than any other object (~10-10-10-11 s/s) Are powered by magnetic field energy, which heats the neutron star interior so th ...
Downloaded - Royal Society Open Science
... All stars experience the ‘red giant branch’ (RGB) phase, when hydrogen in the core is exhausted and the remaining hydrogen burns in a contracting shell as the envelope expands. The extent of convection in the star increases, potentially ‘dredging-up’ already-burnt matter. Eventually, core temperatur ...
... All stars experience the ‘red giant branch’ (RGB) phase, when hydrogen in the core is exhausted and the remaining hydrogen burns in a contracting shell as the envelope expands. The extent of convection in the star increases, potentially ‘dredging-up’ already-burnt matter. Eventually, core temperatur ...
Polarimetry: a powerful diagnostic tool in astronomy
... magnetic fields, or at least its projection on to the sky plane, and has been used to map the magnetic field in our own galaxy. The wavelength dependence of interstellar polarization P(λ), appears to be the same for lines of sight to all stars, and just two parameters are needed to fully describe it ...
... magnetic fields, or at least its projection on to the sky plane, and has been used to map the magnetic field in our own galaxy. The wavelength dependence of interstellar polarization P(λ), appears to be the same for lines of sight to all stars, and just two parameters are needed to fully describe it ...
The effect of helium sedimentation on galaxy cluster masses and
... Sunyaev-Zel’dovich effect (SZE) may be used to infer the helium abundance in the ICM (Markevitch 2007); however, the limited resolution and sensitivity of current SZE interferometers have so far not enabled the measurement of the distribution of helium, even in the cluster cores where the sedimentati ...
... Sunyaev-Zel’dovich effect (SZE) may be used to infer the helium abundance in the ICM (Markevitch 2007); however, the limited resolution and sensitivity of current SZE interferometers have so far not enabled the measurement of the distribution of helium, even in the cluster cores where the sedimentati ...
A Collimated Jet and an Infalling-Rotating Disk in G192.16−3.84
... separated by ∼ 1200 AU. The maser spatio–kinematical structure has well persisted since previous observations, in which the masers are expected to be associated with a highly collimated bipolar jet and an infalling-rotating disk in the northern and southern clusters of H2 O maser features, respectiv ...
... separated by ∼ 1200 AU. The maser spatio–kinematical structure has well persisted since previous observations, in which the masers are expected to be associated with a highly collimated bipolar jet and an infalling-rotating disk in the northern and southern clusters of H2 O maser features, respectiv ...
X. Nuclear star clusters in low-mass early-type galaxies
... also a widely accepted theory for the formation of GCs is still lacking. Bekki et al. (2004) present scaling relations for the sizes of NSCs based on N-body simulations of the merging of equal-mass star clusters; however, they do not predict a relation between host galaxy mass and NSC mass. Antonini ...
... also a widely accepted theory for the formation of GCs is still lacking. Bekki et al. (2004) present scaling relations for the sizes of NSCs based on N-body simulations of the merging of equal-mass star clusters; however, they do not predict a relation between host galaxy mass and NSC mass. Antonini ...
Cosmological Constraints from the Virial Mass
... In this thesis, I present a new determination of the cluster mass function in a volume 107 h -3 Mpc3 using the ROSAT-2MASS-FAST Group Survey (R2FGS). R2FGS is an X-ray-selected sample of systems from the ROSAT All-Sky Survey in the region 6 > 0' and 0.01 < z < 0.06, with target galaxies for each sys ...
... In this thesis, I present a new determination of the cluster mass function in a volume 107 h -3 Mpc3 using the ROSAT-2MASS-FAST Group Survey (R2FGS). R2FGS is an X-ray-selected sample of systems from the ROSAT All-Sky Survey in the region 6 > 0' and 0.01 < z < 0.06, with target galaxies for each sys ...
Analysis of cool DO-type white dwarfs from the Sloan Digital Sky
... (WD), most of them (≈80%) with H-rich atmospheres, corresponding to the DA spectral type. These can be found all along the WD cooling sequence, that is, they have 4 500 ≤ T eff ≤ 170 000 K (Sion 2011). In addition, there are the H-deficient WDs (non-DA WDs), which are usually divided into three subcl ...
... (WD), most of them (≈80%) with H-rich atmospheres, corresponding to the DA spectral type. These can be found all along the WD cooling sequence, that is, they have 4 500 ≤ T eff ≤ 170 000 K (Sion 2011). In addition, there are the H-deficient WDs (non-DA WDs), which are usually divided into three subcl ...
The chemical composition of solar-type stars and its impact on the
... on the gravitational lensing effect of its host star is measured, and pulsar timing, that lead to the first discovery of an exoplanet in 1992. With the pulsar timing method, observers examine small variations in the extremely periodic radio emission pattern of a star, that are caused by planets. How ...
... on the gravitational lensing effect of its host star is measured, and pulsar timing, that lead to the first discovery of an exoplanet in 1992. With the pulsar timing method, observers examine small variations in the extremely periodic radio emission pattern of a star, that are caused by planets. How ...
R585 EXPLORERS OF THE SOUTHERN SKY
... heavenly goddesses to more prosaic constructions. This third, revised and enlarged edition comprises about 40 % more information than was provided with the first one of 1992. ...
... heavenly goddesses to more prosaic constructions. This third, revised and enlarged edition comprises about 40 % more information than was provided with the first one of 1992. ...
Astrophysical Quark Matter
... •strange quark nuggets? (MACHOs?) •gravitational waves from colliding bubbles? •magnetic fields with ~ 100 kpc correlations? •QCD balls as a new CDM candidate? •black holes formation during the transition? ...
... •strange quark nuggets? (MACHOs?) •gravitational waves from colliding bubbles? •magnetic fields with ~ 100 kpc correlations? •QCD balls as a new CDM candidate? •black holes formation during the transition? ...
The masses and spins of neutron stars and stellar
... As we will see, this has a significant impact on the reliability of some types of spin measurement. In distinction to black holes, neutron stars can have their mass changed substantially by accretion from a companion, and the spin magnitudes and directions of accreting neutron stars are essentially ...
... As we will see, this has a significant impact on the reliability of some types of spin measurement. In distinction to black holes, neutron stars can have their mass changed substantially by accretion from a companion, and the spin magnitudes and directions of accreting neutron stars are essentially ...
Th`ese d`astrophysique Chemodynamical Simulations of Evolution
... For a long time galaxies were thought to be “spiral nebulae”, because of their unresolved nature with the available technology of the epoch. In the late 1910’s a few clues arose to show the distant nature of these objects. They scientifically credited the idea first proposed by Kant of “island unive ...
... For a long time galaxies were thought to be “spiral nebulae”, because of their unresolved nature with the available technology of the epoch. In the late 1910’s a few clues arose to show the distant nature of these objects. They scientifically credited the idea first proposed by Kant of “island unive ...
Debris disks from an astronomical and an astrobiological viewpoint Gianni Cataldi
... where a is the semi-major axis (in AU) of the parent body producing the dust, and M∗ the mass of the host star (in units of M⊕ ). Note that tbl is nothing but the orbital period of the parent planetesimal. For the β Pic system tbl ≈ 750 yr, whereas the age is estimated to be 10–20 Myr (Mentuch et al ...
... where a is the semi-major axis (in AU) of the parent body producing the dust, and M∗ the mass of the host star (in units of M⊕ ). Note that tbl is nothing but the orbital period of the parent planetesimal. For the β Pic system tbl ≈ 750 yr, whereas the age is estimated to be 10–20 Myr (Mentuch et al ...
astro-ph/0301519 PDF
... measured abundances do not match the predicted values very well, as reported by other authors in the past. Almost all stars hotter than ~50000K contain heavy elements. For most of these the spread in element abundances is quite narrow and similar to the abundances measured in G191B2B. However, there ...
... measured abundances do not match the predicted values very well, as reported by other authors in the past. Almost all stars hotter than ~50000K contain heavy elements. For most of these the spread in element abundances is quite narrow and similar to the abundances measured in G191B2B. However, there ...
The Physics and Chemistry of Nebular Evolution
... phase, the young protostar and its attendant disk grow by accreting material from the dense core envelope, and typically emit in the microwave regime. The Class I phase is where the natal envelope is being cleared away, most of the protostellar mass has been accreted, and a lower mass disk is presen ...
... phase, the young protostar and its attendant disk grow by accreting material from the dense core envelope, and typically emit in the microwave regime. The Class I phase is where the natal envelope is being cleared away, most of the protostellar mass has been accreted, and a lower mass disk is presen ...
Stars: HR Diagaram Stellar Evolution Astronomy 1 — Elementary Astronomy LA Mission College
... deduced that they were observing very rapidly rotating neutron stars -pulsars. ...
... deduced that they were observing very rapidly rotating neutron stars -pulsars. ...
The Classification of Stellar Spectra
... physical reason for these differences in spectra were not understood until the 1930’s and 1940’s. Then it was realized that, while there were some chemical differences among stars, the main thing that determined the spectral type of a star was its surface temperature. Stars with strong lines of ioni ...
... physical reason for these differences in spectra were not understood until the 1930’s and 1940’s. Then it was realized that, while there were some chemical differences among stars, the main thing that determined the spectral type of a star was its surface temperature. Stars with strong lines of ioni ...
Chapter 19
... helium in a processes called nuclear fusion. • The End Stars usually lose material slowly, but sometimes they can lose material in a big explosion. Much of a star’s material returns to space, where it sometimes forms new stars. Chapter menu ...
... helium in a processes called nuclear fusion. • The End Stars usually lose material slowly, but sometimes they can lose material in a big explosion. Much of a star’s material returns to space, where it sometimes forms new stars. Chapter menu ...
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.