Complete Lecture Notes (pdf file)
... • Individual stars • Binary systems • Star clusters....these reveal how stars evolve with time • Nuclear physics...energy source, synthesis of heavy elements No direct information about physical conditions in stellar interiors (except from helioseismology and solar neutrinos) No direct evidence for ...
... • Individual stars • Binary systems • Star clusters....these reveal how stars evolve with time • Nuclear physics...energy source, synthesis of heavy elements No direct information about physical conditions in stellar interiors (except from helioseismology and solar neutrinos) No direct evidence for ...
spatially resolved spitzer irs spectroscopy of the central region of m82
... Infrared Spectrograph. From these spectra we determined the fluxes and equivalent widths (EWs) of key diagnostic features, such as the [Ne ii] 12.8 m, [Ne iii] 15.5 m, and H2 S(1) 17.03 m lines, and the broad mid-IR polycyclic aromatic hydrocarbon (PAH ) emission features in six representative re ...
... Infrared Spectrograph. From these spectra we determined the fluxes and equivalent widths (EWs) of key diagnostic features, such as the [Ne ii] 12.8 m, [Ne iii] 15.5 m, and H2 S(1) 17.03 m lines, and the broad mid-IR polycyclic aromatic hydrocarbon (PAH ) emission features in six representative re ...
17_Testbank
... E) Although both stars probably formed from the same clump of gas, the more massive one must have had its birth slowed so that it became a main-sequence star millions of years later than its less massive companion. Answer: A 46) Why do scientists think that our solar system must have formed sometime ...
... E) Although both stars probably formed from the same clump of gas, the more massive one must have had its birth slowed so that it became a main-sequence star millions of years later than its less massive companion. Answer: A 46) Why do scientists think that our solar system must have formed sometime ...
![arXiv:1601.01542v1 [astro-ph.GA] 7 Jan 2016](http://s1.studyres.com/store/data/017487687_1-243c4cbda96da53325dd347b0c588a3e-300x300.png)
arXiv:1601.01542v1 [astro-ph.GA] 7 Jan 2016
... studies on the topic and also offers the possibility of properly estimating the oxygen distribution across the entire discs over a distance of up to 3-4 disc effective radii. A proper 2D study of the The classification according to morphological type and into inoxygen abundance distribution that ana ...
... studies on the topic and also offers the possibility of properly estimating the oxygen distribution across the entire discs over a distance of up to 3-4 disc effective radii. A proper 2D study of the The classification according to morphological type and into inoxygen abundance distribution that ana ...
Measuring distances to the edge of the local group
... the early solar system after the inner planets had formed. Two main formation models have been proposed. Wetherill (1980) proposed that planetesimals formed primarily from the agglomeration of dust within the solar nebula. Herndon (2004) showed that this model did not produce sufficiently massive pl ...
... the early solar system after the inner planets had formed. Two main formation models have been proposed. Wetherill (1980) proposed that planetesimals formed primarily from the agglomeration of dust within the solar nebula. Herndon (2004) showed that this model did not produce sufficiently massive pl ...
Bayesian mass and age estimates for transiting exoplanet host stars⋆
... For stars similar to the Sun a change of 80 K in the assumed value of T eff results in a change of about 0.02 dex in the value of [Fe/H]s derived from the analysis of the spectrum (Doyle et al. 2013). This is at least a factor of 3 lower than the minimum standard error that we have assumed for [Fe/H] ...
... For stars similar to the Sun a change of 80 K in the assumed value of T eff results in a change of about 0.02 dex in the value of [Fe/H]s derived from the analysis of the spectrum (Doyle et al. 2013). This is at least a factor of 3 lower than the minimum standard error that we have assumed for [Fe/H] ...
Molecules in Space
... been observed, usually for several different transitions, in a number of molecules including water, OH, SiO, methanol, and ammonia.(33,34) Maser transitions can arise because collisions, typically with dominant species H2 , preferentially populate certain excited states resulting in population inver ...
... been observed, usually for several different transitions, in a number of molecules including water, OH, SiO, methanol, and ammonia.(33,34) Maser transitions can arise because collisions, typically with dominant species H2 , preferentially populate certain excited states resulting in population inver ...
Galactic spiral structure - Proceedings of the Royal Society A
... and a smooth background distribution (figure 2). We smoothed the velocity distribution by replacing each discrete point with a two-dimensional Gaussian function and finding the sum. The choice of smoothing parameter depends on the density of stars in the plot, and the required visual balance between o ...
... and a smooth background distribution (figure 2). We smoothed the velocity distribution by replacing each discrete point with a two-dimensional Gaussian function and finding the sum. The choice of smoothing parameter depends on the density of stars in the plot, and the required visual balance between o ...
The Deaths of Very Massive Stars
... For solar metallicity stars, mass loss may reduce the presupernova mass of the star to a level where it can frequently explode. If it does and the entire envelope has been lost, the explosion will be some sort of Type Ib or IC supernova. Because of the large mass, the light curve would be broad, and ...
... For solar metallicity stars, mass loss may reduce the presupernova mass of the star to a level where it can frequently explode. If it does and the entire envelope has been lost, the explosion will be some sort of Type Ib or IC supernova. Because of the large mass, the light curve would be broad, and ...
3P31.pdf
... On the other hand, the mass of the circumstellar material surrounding “Class I” sources is much smaller, and their molecular outflows are poorly collimated and much less powerful (Bontemps et al 1996). Furuya et al (2001) carried out a water maser survey towards low-mass young stellar objects (using ...
... On the other hand, the mass of the circumstellar material surrounding “Class I” sources is much smaller, and their molecular outflows are poorly collimated and much less powerful (Bontemps et al 1996). Furuya et al (2001) carried out a water maser survey towards low-mass young stellar objects (using ...
Chapter 17--Star Stuff
... itself. The clouds that form stars tend to be quite cold, typically only 10–30 K. (Recall that 0 K is absolute zero, and temperatures on Earth are around 300 K.) They also tend to be quite dense compared to the rest of the gas between the stars, although they would qualify as a superb vacuum by eart ...
... itself. The clouds that form stars tend to be quite cold, typically only 10–30 K. (Recall that 0 K is absolute zero, and temperatures on Earth are around 300 K.) They also tend to be quite dense compared to the rest of the gas between the stars, although they would qualify as a superb vacuum by eart ...
Planet formation around stars of various masses: The snow line and
... of spectral types began with a series of papers by Nakano nearly twenty years ago (Nakano 1987, 1988a,b). More recently, Kornet et al. (2006) considered formation of planets around stars of various masses in situ, while Ida & Lin (2005) examined observable planetary systems resulting from type II mi ...
... of spectral types began with a series of papers by Nakano nearly twenty years ago (Nakano 1987, 1988a,b). More recently, Kornet et al. (2006) considered formation of planets around stars of various masses in situ, while Ida & Lin (2005) examined observable planetary systems resulting from type II mi ...
Astronomy 730 / Galaxies
... (b) S&G 4.7: The mean density of the MW at MMW ~ 1011 M and rMW = 10 kpc is 2.4 × 10-2 M/ pc3. Since tff = √ 1 / Gρ = 272 Myr ~ 300 Myr for the pre-collapse density which is 8 times higher. Since tff ∝ ρ-1/2 ∝ r3/2 M-1/2 we can immediately scale from the MW to Sculptor to find tff ~ 300 (2/10)3/2 ...
... (b) S&G 4.7: The mean density of the MW at MMW ~ 1011 M and rMW = 10 kpc is 2.4 × 10-2 M/ pc3. Since tff = √ 1 / Gρ = 272 Myr ~ 300 Myr for the pre-collapse density which is 8 times higher. Since tff ∝ ρ-1/2 ∝ r3/2 M-1/2 we can immediately scale from the MW to Sculptor to find tff ~ 300 (2/10)3/2 ...
5 Report of the Panel on Stars and Stellar Evolution
... have been imagined, but not yet been observed, such as accretion-induced collapse. Because astronomers understand stars well, they have the confidence to use them as cosmic probes to trace the history of cosmic expansion; but because this understanding is not complete, there is much to learn about t ...
... have been imagined, but not yet been observed, such as accretion-induced collapse. Because astronomers understand stars well, they have the confidence to use them as cosmic probes to trace the history of cosmic expansion; but because this understanding is not complete, there is much to learn about t ...
galaxy formation with cold gas accretion and evolving stellar initial
... are assumed to be independent of galaxy mass and redshift (Bell et al. 2003). As the characteristic mass of the VD08 IMF evolves with time, the correction does depend on galaxy mass and redshift (Marchesini et al. 2009), and determining these dependences is beyond the scope of this paper. For our co ...
... are assumed to be independent of galaxy mass and redshift (Bell et al. 2003). As the characteristic mass of the VD08 IMF evolves with time, the correction does depend on galaxy mass and redshift (Marchesini et al. 2009), and determining these dependences is beyond the scope of this paper. For our co ...
Open clusters in the Third Galactic Quadrant III. Alleged binary
... open cluster catalogue of Dias et al. (2002) lists 7 candidate cluster pairs separated by less than 10 . Pairs filtered out by the selection criteria were Collinder 196/Collinder 198 having b ∼ 6.9◦ ; Ruprecht 27/Alessi 18 because Ruprecht 27 is too old and Alessi 18 is a doubtful cluster appearing ...
... open cluster catalogue of Dias et al. (2002) lists 7 candidate cluster pairs separated by less than 10 . Pairs filtered out by the selection criteria were Collinder 196/Collinder 198 having b ∼ 6.9◦ ; Ruprecht 27/Alessi 18 because Ruprecht 27 is too old and Alessi 18 is a doubtful cluster appearing ...
Document
... 1. Stage 1: Giant Molecular Cloud 2. Stage 2: Protostar 3. Stage 3: T-Tauri 4. Stage 4: Main Sequence 5. Stage 5: Subgiant, Red Giant, Supergiant 6. Stage 6: Core fusion 7. Stage 7: Red Giant or Supergiant 8. Stage 8: Planetary Nebula or Supernova 9. Stage 9: Core Remnant o Stellar Nucleosynthesis o ...
... 1. Stage 1: Giant Molecular Cloud 2. Stage 2: Protostar 3. Stage 3: T-Tauri 4. Stage 4: Main Sequence 5. Stage 5: Subgiant, Red Giant, Supergiant 6. Stage 6: Core fusion 7. Stage 7: Red Giant or Supergiant 8. Stage 8: Planetary Nebula or Supernova 9. Stage 9: Core Remnant o Stellar Nucleosynthesis o ...
File
... * A long time ago, astronomers thought that the Earth was the centre of the Universe. This was called the geocentric model. The evidence for this model came from observations of the sky using the naked eye. After the telescope was invented, astronomers quickly gathered evidence which showed that the ...
... * A long time ago, astronomers thought that the Earth was the centre of the Universe. This was called the geocentric model. The evidence for this model came from observations of the sky using the naked eye. After the telescope was invented, astronomers quickly gathered evidence which showed that the ...
Labeling the HR Diagram - Mastering Physics Answers
... Hint 1. Which gas is hotter? Consider three gas clouds consisting mostly of hydrogen. One cloud has most of its hydrogen in molecular form (H2), one has mostly neutral hydrogen atoms, and one has mostly hydrogen ions (and free electrons). Which cloud is the hottest? ANSWER: the ionized cloud the mol ...
... Hint 1. Which gas is hotter? Consider three gas clouds consisting mostly of hydrogen. One cloud has most of its hydrogen in molecular form (H2), one has mostly neutral hydrogen atoms, and one has mostly hydrogen ions (and free electrons). Which cloud is the hottest? ANSWER: the ionized cloud the mol ...
Astronomy Astrophysics - Max Planck Institut für Radioastronomie
... Context. Accretion and outflow processes are of fundamental importance for our understanding of the formation of stars and planetary systems. To trace these processes, diagnostic spectral lines such as the Brγ 2.166 μm line are widely used, although due to a lack of spatial resolution, the origin of ...
... Context. Accretion and outflow processes are of fundamental importance for our understanding of the formation of stars and planetary systems. To trace these processes, diagnostic spectral lines such as the Brγ 2.166 μm line are widely used, although due to a lack of spatial resolution, the origin of ...
Neon and oxygen in low activity stars: towards a coronal unification
... to additionally increase jointly within allowed errors would provide a sufficient opacity increase. Several objections to this solution were raised, especially from solar observers. A reassessment of solar coronal data from the Solar Maximum Mission led to an upper limit of Ne/O = 0.18 ± 0.04 for acti ...
... to additionally increase jointly within allowed errors would provide a sufficient opacity increase. Several objections to this solution were raised, especially from solar observers. A reassessment of solar coronal data from the Solar Maximum Mission led to an upper limit of Ne/O = 0.18 ± 0.04 for acti ...
1 Astrobiologically Interesting Stars within 10
... disrupted. Masses larger than 1.20 solar may remain acceptable if allowance is made for a faster evolution of complex life than was the case on Earth. Yet, besides these well-accepted notions, quite a few other considerations have recently been increasingly considered as playing fundamental roles fo ...
... disrupted. Masses larger than 1.20 solar may remain acceptable if allowance is made for a faster evolution of complex life than was the case on Earth. Yet, besides these well-accepted notions, quite a few other considerations have recently been increasingly considered as playing fundamental roles fo ...
3 science case - Giant Magellan Telescope Organization
... planetary systems completely unlike our own, we are now also confronted with a need to understand the diversity of solar systems and ask how often planets develop the conditions needed to support life. With ...
... planetary systems completely unlike our own, we are now also confronted with a need to understand the diversity of solar systems and ask how often planets develop the conditions needed to support life. With ...
Hertzsprung–Russell diagram - Wikipedia, the free encyclopedia
... The original diagram displayed the spectral type of stars on the horizontal axis and the absolute visual magnitude on the vertical axis. The spectral type is not a numerical quantity, but the sequence of spectral types is a monotonic series ordered by stellar surface temperature. Modern observationa ...
... The original diagram displayed the spectral type of stars on the horizontal axis and the absolute visual magnitude on the vertical axis. The spectral type is not a numerical quantity, but the sequence of spectral types is a monotonic series ordered by stellar surface temperature. Modern observationa ...
H II region
An H II region is a large, low-density cloud of partially ionized gas in which star formation has recently taken place. The short-lived blue stars forged in these regions emit copious amounts of ultraviolet light that ionize the surrounding gas. H II regions—sometimes several hundred light-years across—are often associated with giant molecular clouds. The first known H II region was the Orion Nebula, which was discovered in 1610 by Nicolas-Claude Fabri de Peiresc.H II regions are named for the large amount of ionised atomic hydrogen they contain, referred to as H II, pronounced H-two by astronomers (an H I region being neutral atomic hydrogen, and H2 being molecular hydrogen). Such regions have extremely diverse shapes, because the distribution of the stars and gas inside them is irregular. They often appear clumpy and filamentary, sometimes showing bizarre shapes such as the Horsehead Nebula. H II regions may give birth to thousands of stars over a period of several million years. In the end, supernova explosions and strong stellar winds from the most massive stars in the resulting star cluster will disperse the gases of the H II region, leaving behind a cluster of birthed stars such as the Pleiades.H II regions can be seen to considerable distances in the universe, and the study of extragalactic H II regions is important in determining the distance and chemical composition of other galaxies. Spiral and irregular galaxies contain many H II regions, while elliptical galaxies are almost devoid of them. In the spiral galaxies, including the Milky Way, H II regions are concentrated in the spiral arms, while in the irregular galaxies they are distributed chaotically. Some galaxies contain huge H II regions, which may contain tens of thousands of stars. Examples include the 30 Doradus region in the Large Magellanic Cloud and NGC 604 in the Triangulum Galaxy.