AN INTERSTELLAR CLOUD WITH A HIGH CON
... The Doppler shifts of the interstellar lines given in Table 1 provide some specific evidence in favor of the idea that they originate in a volume near to the emission region. Applying a correction for solar motion of +7.5 km/sec, with a value A = 15 km/sec kpc for Oort's constant (Kraft and Schmidt ...
... The Doppler shifts of the interstellar lines given in Table 1 provide some specific evidence in favor of the idea that they originate in a volume near to the emission region. Applying a correction for solar motion of +7.5 km/sec, with a value A = 15 km/sec kpc for Oort's constant (Kraft and Schmidt ...
A little bit of Everything - Jefferson School District
... system. It is large and is composed of many gases. You would expect this new planet to be located here. ...
... system. It is large and is composed of many gases. You would expect this new planet to be located here. ...
A new isolated dSph galaxy near the Local Group
... We determine the quantitative star formation and metal enrichment history of KKs 3 from the CMD using our STARPROBE program. The program develops an approximation to the observed distribution of stars in the CMD using a positive linear combination of synthetic diagrams formed by simple stellar popul ...
... We determine the quantitative star formation and metal enrichment history of KKs 3 from the CMD using our STARPROBE program. The program develops an approximation to the observed distribution of stars in the CMD using a positive linear combination of synthetic diagrams formed by simple stellar popul ...
Read the article
... the micro-spiral could be zigzag, or helical. While a few stars spiral inside the micro-spiral center, some appear to be ejected from it. The IRS 16SW forms a bridge between the IRS 16 complex and the center of the microspiral, where several spring like helical structures can be observed. In fact, t ...
... the micro-spiral could be zigzag, or helical. While a few stars spiral inside the micro-spiral center, some appear to be ejected from it. The IRS 16SW forms a bridge between the IRS 16 complex and the center of the microspiral, where several spring like helical structures can be observed. In fact, t ...
Astronomy Astrophysics MY Camelopardalis, a very massive merger progenitor &
... slightly above one day. We intend to confirm this orbital period and derive orbital and stellar parameters. Methods. Timing analysis of a very exhaustive (4607 points) light curve indicates a period of 1.1754514 ± 0.0000015 d. Highresolution spectra and the cross-correlation technique implemented in ...
... slightly above one day. We intend to confirm this orbital period and derive orbital and stellar parameters. Methods. Timing analysis of a very exhaustive (4607 points) light curve indicates a period of 1.1754514 ± 0.0000015 d. Highresolution spectra and the cross-correlation technique implemented in ...
Measuring the Masses of Neutron Stars
... (or disrupted) double neutron star remains, like the Hulse-Taylor binary pulsar PSR 1913+16 (or a neutron star – white dwarf system, if the mass of the Be companion is less than 8 M A). In HMXBs with an orbital period less than about a year the compact object will enter the core of the OB companion ...
... (or disrupted) double neutron star remains, like the Hulse-Taylor binary pulsar PSR 1913+16 (or a neutron star – white dwarf system, if the mass of the Be companion is less than 8 M A). In HMXBs with an orbital period less than about a year the compact object will enter the core of the OB companion ...
BML_V
... its intrinsic size, and by its environment: this is the robust approach used by eALFA. The second context is by studying the multitude of processes involved in our Galaxy's interstellar medium (ISM), as it is buffetted by accretion, star formation, and conditioned by turbulence and magnetic fields. ...
... its intrinsic size, and by its environment: this is the robust approach used by eALFA. The second context is by studying the multitude of processes involved in our Galaxy's interstellar medium (ISM), as it is buffetted by accretion, star formation, and conditioned by turbulence and magnetic fields. ...
The End of the Dark Ages
... 2.2. What were the properties of the first stars ? Star formation in the early universe is usually assumed to be understood more easily because several complicating effects can be neglected to a first approximation: among these are magnetic fields, dust grains and metal enrichment. Yet little consen ...
... 2.2. What were the properties of the first stars ? Star formation in the early universe is usually assumed to be understood more easily because several complicating effects can be neglected to a first approximation: among these are magnetic fields, dust grains and metal enrichment. Yet little consen ...
The Interstellar Medium (ISM) The Dust The Gas: a. The Hot
... Dense, dark regions — Dark Dust Clouds High density: 105 per cm3 molecular hydrogen H2 . Cold Temperature: about 20K Molecular emissions formation of molecules — cool, low energy environment requires dust grains. Types of molecules Organic molecules; pre-biotic? possible detection of amino acid glyc ...
... Dense, dark regions — Dark Dust Clouds High density: 105 per cm3 molecular hydrogen H2 . Cold Temperature: about 20K Molecular emissions formation of molecules — cool, low energy environment requires dust grains. Types of molecules Organic molecules; pre-biotic? possible detection of amino acid glyc ...
Summer Sky Tour
... sun is a yellow star, about 10,000°F at the surface. A red star is about half the sun's surface temperature, whereas a blue star is three to five times as hot as the sun. White stars are somewhere between the yellow ones and blue ones. Now, all stars are made of pretty much the same stuff -- about 9 ...
... sun is a yellow star, about 10,000°F at the surface. A red star is about half the sun's surface temperature, whereas a blue star is three to five times as hot as the sun. White stars are somewhere between the yellow ones and blue ones. Now, all stars are made of pretty much the same stuff -- about 9 ...
proposed research projects for pparc gemini studentships
... systems to establish the links between the properties of their stellar populations (ages and chemical abundances) and their kinematic properties (masses and dynamics). GEMINI spectroscopy will allow us to measure kinematics and line strengths out to large radii. We will combine this information with ...
... systems to establish the links between the properties of their stellar populations (ages and chemical abundances) and their kinematic properties (masses and dynamics). GEMINI spectroscopy will allow us to measure kinematics and line strengths out to large radii. We will combine this information with ...
Modified Newtonian Mechanics
... explanation. This hidden mass hypothesis has been widely accepted even though it raises a really tough question for which there is not yet an answer. Where did all that hidden mass come from? Cosmology suggests that hydrogen was first developed and then came together and formed stars. In the stars, ...
... explanation. This hidden mass hypothesis has been widely accepted even though it raises a really tough question for which there is not yet an answer. Where did all that hidden mass come from? Cosmology suggests that hydrogen was first developed and then came together and formed stars. In the stars, ...
The white dwarf cooling sequence of 47 Tucanae
... dwarf formation rate. Thus, the position in the sorted list is proportional to the time spent on the cooling sequence. Their sorted, completeness-corrected distribution of effective temperatures is shown Fig. 2 as a grey shaded band, which includes the 1σ statistical errors. Also shown for illustrat ...
... dwarf formation rate. Thus, the position in the sorted list is proportional to the time spent on the cooling sequence. Their sorted, completeness-corrected distribution of effective temperatures is shown Fig. 2 as a grey shaded band, which includes the 1σ statistical errors. Also shown for illustrat ...
Notes (PowerPoint)
... o Inner four planets solid (earth), outer gaseous • Planets shine with steady light (stars twinkle because of small size), wander, near plane of sun ...
... o Inner four planets solid (earth), outer gaseous • Planets shine with steady light (stars twinkle because of small size), wander, near plane of sun ...
The cooling of CO white dwarfs: influence of the internal chemical
... on the main sequence. Since they have exhausted all their nuclear fuel, their evolution is just a gravothermal process. The release of energy only depends on the detailed internal structure and chemical composition and on the properties of the envelope equation of state and opacity; its consequences ...
... on the main sequence. Since they have exhausted all their nuclear fuel, their evolution is just a gravothermal process. The release of energy only depends on the detailed internal structure and chemical composition and on the properties of the envelope equation of state and opacity; its consequences ...
More detailed notes
... You may have noticed that, apart from 7Li made in BBN, we have not accounted for the light elements between helium and carbon. These are noticeably uncommon, as can be seen in the first plot on page 2, but they do exist, so they must be formed somehow. They are definitely not made by fusion, since ( ...
... You may have noticed that, apart from 7Li made in BBN, we have not accounted for the light elements between helium and carbon. These are noticeably uncommon, as can be seen in the first plot on page 2, but they do exist, so they must be formed somehow. They are definitely not made by fusion, since ( ...
Expected Coalescence Rates of NS/NS Binaries for Ground Based
... fb : fraction of massive binaries formed among all stars ...
... fb : fraction of massive binaries formed among all stars ...
Linking Asteroids and Meteorites through Reflectance
... • The bulge is at the center of the galaxy, is a flattened spheroid • This is a high density region where red stars predominate, which are very old and about 10 billion years old • There is growing evidence for a very massive black hole at its center ...
... • The bulge is at the center of the galaxy, is a flattened spheroid • This is a high density region where red stars predominate, which are very old and about 10 billion years old • There is growing evidence for a very massive black hole at its center ...
Placing Our Solar System in Context
... rare among sun-like stars in the Milky Way galaxy? Primordial Disk Evolution: - disks around lower mass stars are less massive and live longer than their more massive counterparts. - large dispersion in evolutionary times could indicate dispersion in initial conditions. - evolution appears to procee ...
... rare among sun-like stars in the Milky Way galaxy? Primordial Disk Evolution: - disks around lower mass stars are less massive and live longer than their more massive counterparts. - large dispersion in evolutionary times could indicate dispersion in initial conditions. - evolution appears to procee ...
... – Stars travel around the center of the galaxy in their own orbits – Stars and gas traveling in the disc will bunch up as they enter an arm and will spread out as they leave – This bunching is similar to that of cars on a freeway except gravity causes the bunching of the stars – Gas entering the arm ...
Chapter 15
... • These population III stars may not be observable for three reasons – Only short-lived massive population III stars can form – consequently none are left today – Population III stars exist, but are masquerading as Pop II since their atmospheres have been contaminated by gas ejected when a more mass ...
... • These population III stars may not be observable for three reasons – Only short-lived massive population III stars can form – consequently none are left today – Population III stars exist, but are masquerading as Pop II since their atmospheres have been contaminated by gas ejected when a more mass ...
Beatrice Muriel Hill Tinsley
... lifetimes, brightnesses, and colours (temperatures) and will host the same set of nuclear reactions, making about the same amounts of carbon, oxygen, iron, and other heavy elements out of the hydrogen and helium they began with. The stars that make most of the heavy elements have short lives, and so ...
... lifetimes, brightnesses, and colours (temperatures) and will host the same set of nuclear reactions, making about the same amounts of carbon, oxygen, iron, and other heavy elements out of the hydrogen and helium they began with. The stars that make most of the heavy elements have short lives, and so ...
2P10.pdf
... with an accuracy sufficient for the quantitative description of the chemical and dynamical evolution of the Galaxy over all galactocentric distances. To reconstruct the formation history of the Milky Way and its structure is necessary to determine the abundance of Fe and α-elements separatelly, and ...
... with an accuracy sufficient for the quantitative description of the chemical and dynamical evolution of the Galaxy over all galactocentric distances. To reconstruct the formation history of the Milky Way and its structure is necessary to determine the abundance of Fe and α-elements separatelly, and ...
Main sequence
In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell. Stars on this band are known as main-sequence stars or ""dwarf"" stars.After a star has formed, it generates thermal energy in the dense core region through the nuclear fusion of hydrogen atoms into helium. During this stage of the star's lifetime, it is located along the main sequence at a position determined primarily by its mass, but also based upon its chemical composition and other factors. All main-sequence stars are in hydrostatic equilibrium, where outward thermal pressure from the hot core is balanced by the inward pressure of gravitational collapse from the overlying layers. The strong dependence of the rate of energy generation in the core on the temperature and pressure helps to sustain this balance. Energy generated at the core makes its way to the surface and is radiated away at the photosphere. The energy is carried by either radiation or convection, with the latter occurring in regions with steeper temperature gradients, higher opacity or both.The main sequence is sometimes divided into upper and lower parts, based on the dominant process that a star uses to generate energy. Stars below about 1.5 times the mass of the Sun (or 1.5 solar masses (M☉)) primarily fuse hydrogen atoms together in a series of stages to form helium, a sequence called the proton–proton chain. Above this mass, in the upper main sequence, the nuclear fusion process mainly uses atoms of carbon, nitrogen and oxygen as intermediaries in the CNO cycle that produces helium from hydrogen atoms. Main-sequence stars with more than two solar masses undergo convection in their core regions, which acts to stir up the newly created helium and maintain the proportion of fuel needed for fusion to occur. Below this mass, stars have cores that are entirely radiative with convective zones near the surface. With decreasing stellar mass, the proportion of the star forming a convective envelope steadily increases, whereas main-sequence stars below 0.4 M☉ undergo convection throughout their mass. When core convection does not occur, a helium-rich core develops surrounded by an outer layer of hydrogen.In general, the more massive a star is, the shorter its lifespan on the main sequence. After the hydrogen fuel at the core has been consumed, the star evolves away from the main sequence on the HR diagram. The behavior of a star now depends on its mass, with stars below 0.23 M☉ becoming white dwarfs directly, whereas stars with up to ten solar masses pass through a red giant stage. More massive stars can explode as a supernova, or collapse directly into a black hole.