Carbon-enhanced metal-poor stars in dwarf galaxies
... [Fe/H]≤ −4.5 are CEMP-no stars. These objects have peculiar chemical abundance patterns consistent with the yields predicted for primordial faint SN (e.g. Iwamoto et al. 2005). However, we also note that these extreme stars are part of a common, global trend, which involves stars in both the Galacti ...
... [Fe/H]≤ −4.5 are CEMP-no stars. These objects have peculiar chemical abundance patterns consistent with the yields predicted for primordial faint SN (e.g. Iwamoto et al. 2005). However, we also note that these extreme stars are part of a common, global trend, which involves stars in both the Galacti ...
PPT - Chandra X
... 2. Fit the ungrouped spectrum (CSTAT statistics, Powell optimization, kT1 [0.01-1 keV] and kT2 [1-10 kev], fixed Abund = 0.3 Solar) 3. Fit the grouped spectrum (Chi-squared data-variance statistics, Levenberg-Marquardt optimization, kT1 [0.01-2] and kT2 [1-10] keV 4. If E(B-V) is unknown, fit again ...
... 2. Fit the ungrouped spectrum (CSTAT statistics, Powell optimization, kT1 [0.01-1 keV] and kT2 [1-10 kev], fixed Abund = 0.3 Solar) 3. Fit the grouped spectrum (Chi-squared data-variance statistics, Levenberg-Marquardt optimization, kT1 [0.01-2] and kT2 [1-10] keV 4. If E(B-V) is unknown, fit again ...
GCR Neon Isotopic Abundances: Comparison with Wolf
... and WN phases. Large quantities of He-burning material rich in 22Ne are expelled from the stars when they are in the WC phase, resulting in greatly enhanced 22Ne/20Ne ratios. In the WN phase of WR stars, CNO cycling dominates with the resultant production of high 13C/12C and 14N/16O ratios, but no e ...
... and WN phases. Large quantities of He-burning material rich in 22Ne are expelled from the stars when they are in the WC phase, resulting in greatly enhanced 22Ne/20Ne ratios. In the WN phase of WR stars, CNO cycling dominates with the resultant production of high 13C/12C and 14N/16O ratios, but no e ...
Spectral Classification: The First Step in Quantitative Spectral Analysis
... The MK Spectral type is a Fundamental Datum of Astronomy if • The spectral type is obtained solely through comparison with standards • Theory & external sources of information are not used in the determination of the spectral type If these two principles are followed, the spectral type can serve as ...
... The MK Spectral type is a Fundamental Datum of Astronomy if • The spectral type is obtained solely through comparison with standards • Theory & external sources of information are not used in the determination of the spectral type If these two principles are followed, the spectral type can serve as ...
Measurements of Neutron Star Masses
... eating the phase structure of dense cold quark eventually squeezed out at densities near n0 (32). If so, beginning at about 0.1 n0, there matter (35) has yielded novel states of matter, Motivation 1. Nuclear equation of state. could be a continuous change of the dimenincluding color-superconducting ...
... eating the phase structure of dense cold quark eventually squeezed out at densities near n0 (32). If so, beginning at about 0.1 n0, there matter (35) has yielded novel states of matter, Motivation 1. Nuclear equation of state. could be a continuous change of the dimenincluding color-superconducting ...
The Interstellar Medium In Galaxies Seen A
... obscuration of galaxies during the first 3 billion years of cosmic time (z>4)13 . This evolution implies a change in the average interstellar medium properties, but the measurements are systematically uncertain due to untested assumptions4,5, and the inability to measure heavily obscured regions of ...
... obscuration of galaxies during the first 3 billion years of cosmic time (z>4)13 . This evolution implies a change in the average interstellar medium properties, but the measurements are systematically uncertain due to untested assumptions4,5, and the inability to measure heavily obscured regions of ...
astronomy (astr)
... structure, and the growth of that structure though time. Requisites: Prerequisites, ASTR 301 and PHYS 401; pre- or corequisite, PHYS 321. Grading status: Letter grade. ASTR 505. Physics of Interstellar Gas. 3 Credits. Surveys the physical processes governing the interstellar medium (ISM), which take ...
... structure, and the growth of that structure though time. Requisites: Prerequisites, ASTR 301 and PHYS 401; pre- or corequisite, PHYS 321. Grading status: Letter grade. ASTR 505. Physics of Interstellar Gas. 3 Credits. Surveys the physical processes governing the interstellar medium (ISM), which take ...
Hands-on Gravitational Wave Astronomy
... could begin registering the gravitational waves that the system emits. At earlier times in the process, when the neutron stars are orbiting more slowly and at a greater distance from each other, a space-based detector such as the forthcoming LISA could sense the long period, low-frequency gravitatio ...
... could begin registering the gravitational waves that the system emits. At earlier times in the process, when the neutron stars are orbiting more slowly and at a greater distance from each other, a space-based detector such as the forthcoming LISA could sense the long period, low-frequency gravitatio ...
T Tauri stars Optical lucky imaging polarimetry of HL and XZ Tau
... the surrounding medium. This continues until the central temperature reaches T ∼2000 K and at that point H2 dissociates, thus absorbing thermal energy causing a break in the hydrostatic balance. The breaking causes a second collapse which continues until all the H2 is exhausted and a subsequent hydr ...
... the surrounding medium. This continues until the central temperature reaches T ∼2000 K and at that point H2 dissociates, thus absorbing thermal energy causing a break in the hydrostatic balance. The breaking causes a second collapse which continues until all the H2 is exhausted and a subsequent hydr ...
norfolk skies - Norfolk Astronomical Society
... method described above. The nebula forms the apex of a triangle with two stars of equal brightness. Good luck on this difficult object. NGC 2327 - An interesting nebula extending north from a faint double star. It reminds me of the more famous NGC 2261 in Monocerous (Hubble’s Variable Nebula) becaus ...
... method described above. The nebula forms the apex of a triangle with two stars of equal brightness. Good luck on this difficult object. NGC 2327 - An interesting nebula extending north from a faint double star. It reminds me of the more famous NGC 2261 in Monocerous (Hubble’s Variable Nebula) becaus ...
L17 SHELL-SHOCKED DIFFUSION MODEL FOR THE LIGHT
... our simple analytic light curve in Figure 1 is surely an oversimplification of the actual situation. The density profile resulting from the impact of the SN debris with an opaque shell will not be a homogeneous sphere, and the internal impact may continue over a timescale comparable to or greater th ...
... our simple analytic light curve in Figure 1 is surely an oversimplification of the actual situation. The density profile resulting from the impact of the SN debris with an opaque shell will not be a homogeneous sphere, and the internal impact may continue over a timescale comparable to or greater th ...
outer-disk populations in ngc 7793: evidence for stellar
... populations at 280 (∼5.1 kpc). Beyond this disk break, the profiles become steeper for younger populations. This same trend is seen in numerical simulations where the outer disk is formed almost entirely by radial migration. We also found that the older stars of NGC 7793 extend significantly farth ...
... populations at 280 (∼5.1 kpc). Beyond this disk break, the profiles become steeper for younger populations. This same trend is seen in numerical simulations where the outer disk is formed almost entirely by radial migration. We also found that the older stars of NGC 7793 extend significantly farth ...
Life Histories Of Some Stars
... all? Describe the shape of the graph? Is it a straight line? A curve? 5. Give each group the list of stars attached and the HR diagram attached. Instead of height and weight, the information is in Luminosity (compared to sun) and Surface Temperature (in K). The chart also gives the star’s current st ...
... all? Describe the shape of the graph? Is it a straight line? A curve? 5. Give each group the list of stars attached and the HR diagram attached. Instead of height and weight, the information is in Luminosity (compared to sun) and Surface Temperature (in K). The chart also gives the star’s current st ...
Senior thesis - University of Texas Astronomy Home Page
... Our sun, as with the inhabitants of its solar system, has a finite lifetime. Six billion years from now, distant aliens looking upon our solar system will not see the familiar middleaged star providing the earth with life-sustaining warmth, but rather an extremely hot and dense white dwarf. The sun’ ...
... Our sun, as with the inhabitants of its solar system, has a finite lifetime. Six billion years from now, distant aliens looking upon our solar system will not see the familiar middleaged star providing the earth with life-sustaining warmth, but rather an extremely hot and dense white dwarf. The sun’ ...
Document
... diagram at right. What is invariably observed instead is that rotation curves tend to remain high as far out as they can be measured. This implies the existence of massive halos of dark matter in galaxies. The nature of the material comprising this dark matter is completely unknown at present, makin ...
... diagram at right. What is invariably observed instead is that rotation curves tend to remain high as far out as they can be measured. This implies the existence of massive halos of dark matter in galaxies. The nature of the material comprising this dark matter is completely unknown at present, makin ...
The Evening Sky Map
... Double Star – Two stars that appear close to each other in the sky; either linked by gravity so that they orbit each other (binary star) or lying at different distances from Earth (optical double). Apparent separation of stars is given in seconds of arc ("). Ecliptic – The path of the Sun’s center o ...
... Double Star – Two stars that appear close to each other in the sky; either linked by gravity so that they orbit each other (binary star) or lying at different distances from Earth (optical double). Apparent separation of stars is given in seconds of arc ("). Ecliptic – The path of the Sun’s center o ...
Disk evolution: dust and gas\*
... The basic idea is that the inner disk is extremely opaque and thus cannot efficiently radiate away energy that has been inserted into the gas through the viscous accretion process. The inner disk could then be hotter than 104 K. This also implies that the original assumption of a thin disk (disk heigh ...
... The basic idea is that the inner disk is extremely opaque and thus cannot efficiently radiate away energy that has been inserted into the gas through the viscous accretion process. The inner disk could then be hotter than 104 K. This also implies that the original assumption of a thin disk (disk heigh ...
Tracing the evolution of NGC 6397 through the chemical
... of fast rotating massive star”-scenario. Methods. High-resolution spectra were obtained with the FLAMES/UVES spectrograph on the VLT. We determined non-LTE abundances of Na, and LTE abundances for the remaining 21 elements, including O (from the [OI] line at 630 nm), Mg, Al, α, iron-peak, and neutro ...
... of fast rotating massive star”-scenario. Methods. High-resolution spectra were obtained with the FLAMES/UVES spectrograph on the VLT. We determined non-LTE abundances of Na, and LTE abundances for the remaining 21 elements, including O (from the [OI] line at 630 nm), Mg, Al, α, iron-peak, and neutro ...
Oxygen Chemistry on Dust Grains
... ! NH3 oxidation relevant in hot core/corino away from the core (cold regions) ! Detection can be tricky because of the timing of the release of NH2OH in the gas ...
... ! NH3 oxidation relevant in hot core/corino away from the core (cold regions) ! Detection can be tricky because of the timing of the release of NH2OH in the gas ...
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.