The Earliest Stages of Star and Planet Formation: Core Collapse
... the advent of millimeter and sub-millimeter arrays, there is now clear evidence from molecular line observations that some protoplanetary disks have Keplerian velocity fields, indicating rotational support (e.g., ALMA observations of TW Hydra; see § 2 on observations of early disks). Indirect eviden ...
... the advent of millimeter and sub-millimeter arrays, there is now clear evidence from molecular line observations that some protoplanetary disks have Keplerian velocity fields, indicating rotational support (e.g., ALMA observations of TW Hydra; see § 2 on observations of early disks). Indirect eviden ...
The physico-chemical history of Falling Evaporating Bodies around
... ∼0.4 AU; see Beust et al. 1998). Consequently, in our approach, we need only consider the process of evaporation. Dust is thus considered as inert matter, which does not react in any way and whose thermodynamic properties are taken from the literature. The FEB is assumed to orbit the star on a circu ...
... ∼0.4 AU; see Beust et al. 1998). Consequently, in our approach, we need only consider the process of evaporation. Dust is thus considered as inert matter, which does not react in any way and whose thermodynamic properties are taken from the literature. The FEB is assumed to orbit the star on a circu ...
13 – Synthesis of heavier elements
... - The core expands due to the huge temperature in the core. - The luminosity decreases. - The slower rate of energy production makes the outer layers contract and thus they also heat up, leading to an increase of the surface temperature T. Low-mass stars end up their productive life by ejecting t ...
... - The core expands due to the huge temperature in the core. - The luminosity decreases. - The slower rate of energy production makes the outer layers contract and thus they also heat up, leading to an increase of the surface temperature T. Low-mass stars end up their productive life by ejecting t ...
Masses of Dwarf Satellites of the Milky Way
... Q, for 526 subhaloes in the main halo of the Aq-A-1 simulation. haloes considered contain between 20 000 and nearly ∼10 million . The lines in different colours show averages in logarithmic mass each of the three profiles. ...
... Q, for 526 subhaloes in the main halo of the Aq-A-1 simulation. haloes considered contain between 20 000 and nearly ∼10 million . The lines in different colours show averages in logarithmic mass each of the three profiles. ...
The Stromgren sphere around the highest-redshift QSOs
... Discussions • Further issues related to long-term evolution of accretion disks: – Disk winds, infalling material deposited onto the disk, instabilities, self-gravitating disks, star formation … • Binary black holes and coevolution of galaxies and QSOs/AGNs ...
... Discussions • Further issues related to long-term evolution of accretion disks: – Disk winds, infalling material deposited onto the disk, instabilities, self-gravitating disks, star formation … • Binary black holes and coevolution of galaxies and QSOs/AGNs ...
the first three thresholds - McGraw
... again to form a new universe (see Chapter 13). Another speculation, which is now taken more seriously, is that there is a vast multidimensional “multiverse” within which universes keep appearing, each with its own distinctive features, so that our universe may be one of countless billions of univers ...
... again to form a new universe (see Chapter 13). Another speculation, which is now taken more seriously, is that there is a vast multidimensional “multiverse” within which universes keep appearing, each with its own distinctive features, so that our universe may be one of countless billions of univers ...
A Note on the Mixing Length Theory and Massive Star Evolution
... luminosity), a very extended convective envelope develop. Different ways of dealing with convection lead to very different results on the properties of the stellar model as regards structure, pulsation and evolution. When the classical MLT is applied in the case of late type supergiants (yellow and ...
... luminosity), a very extended convective envelope develop. Different ways of dealing with convection lead to very different results on the properties of the stellar model as regards structure, pulsation and evolution. When the classical MLT is applied in the case of late type supergiants (yellow and ...
Planet formation
... form of icy grains, and dust grains have sufficiently low temperatures to capture ice molecules in their mantles. The Snow line is crucial for the planet formation process, as ice-covered grains are suggested to have transported the gaseous material for the gas giants atmospheres onto their rocky co ...
... form of icy grains, and dust grains have sufficiently low temperatures to capture ice molecules in their mantles. The Snow line is crucial for the planet formation process, as ice-covered grains are suggested to have transported the gaseous material for the gas giants atmospheres onto their rocky co ...
Distance determination for RAVE stars using stellar models
... used to illuminate a host of substructures in the Galactic halo. The strength of photometric distances is that they can be constructed for a wide range of stellar populations. An important recent study was carried out by Ivezić et al. (2008). In this work they took high-precision multi-band optical ...
... used to illuminate a host of substructures in the Galactic halo. The strength of photometric distances is that they can be constructed for a wide range of stellar populations. An important recent study was carried out by Ivezić et al. (2008). In this work they took high-precision multi-band optical ...
Chapter 2 Ionization Front Physics
... disks as their massive central stars emerge onto the main sequence were done by Yorke & Welz in 1996 [57] and are yet another example of the ubiquity of H II regions in stellar and galactic environments. Numerical simulation of H II regions today falls into two classes: photoionization calculations ...
... disks as their massive central stars emerge onto the main sequence were done by Yorke & Welz in 1996 [57] and are yet another example of the ubiquity of H II regions in stellar and galactic environments. Numerical simulation of H II regions today falls into two classes: photoionization calculations ...
Bez nadpisu
... are different because we view the region where the stream and the outer parts of the disk interact from different angles. On the other hand, the depths of the minima are different because the “nose” of the red star, which is turned toward the white dwarf, is heated by radiation from the disk. After ...
... are different because we view the region where the stream and the outer parts of the disk interact from different angles. On the other hand, the depths of the minima are different because the “nose” of the red star, which is turned toward the white dwarf, is heated by radiation from the disk. After ...
1Lec_1 - The University of Texas at Dallas
... rest of the elements in the periodic table. The cloud of elements blown out into space as “cosmic dust” after a nova event is called a “nebula”: The “Crab nebula”: (in our Milky Way galaxy) “Cosmic dust” ...
... rest of the elements in the periodic table. The cloud of elements blown out into space as “cosmic dust” after a nova event is called a “nebula”: The “Crab nebula”: (in our Milky Way galaxy) “Cosmic dust” ...
PDF format
... True or False?: If a black hole ten times more massive than our Sun were lurking just beyond Pluto's orbit, we'd have no way of knowing it was there. a) True. Black holes do not emit light so they cannot be detected. b) True. Such a low mass black hole would have no influence on the solar system. ...
... True or False?: If a black hole ten times more massive than our Sun were lurking just beyond Pluto's orbit, we'd have no way of knowing it was there. a) True. Black holes do not emit light so they cannot be detected. b) True. Such a low mass black hole would have no influence on the solar system. ...
Circumstellar dust shells around long-period variables
... variables (P≥400 days; Jura 1986). Candidates that could be considered are for instance AFGL 190 (Tcol ∼ 300 K; Gehrz & Hackwell 1976) or AFGL 5250 ([K–L] > 7; Fouqué et al. 1992). Nevertheless, for our study we selected AFGL 3068 because it is the brightest and best studied specimen, having the hi ...
... variables (P≥400 days; Jura 1986). Candidates that could be considered are for instance AFGL 190 (Tcol ∼ 300 K; Gehrz & Hackwell 1976) or AFGL 5250 ([K–L] > 7; Fouqué et al. 1992). Nevertheless, for our study we selected AFGL 3068 because it is the brightest and best studied specimen, having the hi ...
Orbital period decay of compact black hole X
... detailed evolutionary sequences of a BHXB with an initial orbital period of 0.9 d, which consist of a 5.0 M BH and a 3.0 M donor star. The calculation shows that if the fraction of the transferred mass feeds into the circumbinary disk δ is greater than 0.00035, the mass transfer becomes dynamicall ...
... detailed evolutionary sequences of a BHXB with an initial orbital period of 0.9 d, which consist of a 5.0 M BH and a 3.0 M donor star. The calculation shows that if the fraction of the transferred mass feeds into the circumbinary disk δ is greater than 0.00035, the mass transfer becomes dynamicall ...
Infrared Photometry of Red Supergiants in Young Clusters in the
... between the lower metallicity NGC 330 RSG and those of the more metal rich LMC clusters. The solid segment of the evolutionary track in figure 3 is the down slope of the red giant branch in which models predict the red supergiants spend ∼75% of their lives when cooler than log Tef f =3.8. The spread ...
... between the lower metallicity NGC 330 RSG and those of the more metal rich LMC clusters. The solid segment of the evolutionary track in figure 3 is the down slope of the red giant branch in which models predict the red supergiants spend ∼75% of their lives when cooler than log Tef f =3.8. The spread ...
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... A twofold model of turbulent accretion for massive star formation was proposed by Krumholz et al. (2006), where Bondi accretion is assumed, with the Bondi velocity dispersion set either to the turbulent velocity dispersion or to the velocity dispersion due to vorticity. Models of accretion onto a st ...
... A twofold model of turbulent accretion for massive star formation was proposed by Krumholz et al. (2006), where Bondi accretion is assumed, with the Bondi velocity dispersion set either to the turbulent velocity dispersion or to the velocity dispersion due to vorticity. Models of accretion onto a st ...
Gaia talk
... The imaging data is being processed in Cambridge. 6 billion transits processed so far ...
... The imaging data is being processed in Cambridge. 6 billion transits processed so far ...
Magnetic cycles of Sun-like stars with different levels of coronal and
... stars. Durations of CA cycles, found for 50 different stars of late spectral classes (F, G and K), vary from 7 to 20 years according to HK-project observations. Currently, there are several databases that include thousands of stars with measured fluxes in the chromospheric lines of CaII H&K emission ...
... stars. Durations of CA cycles, found for 50 different stars of late spectral classes (F, G and K), vary from 7 to 20 years according to HK-project observations. Currently, there are several databases that include thousands of stars with measured fluxes in the chromospheric lines of CaII H&K emission ...
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.