argo and other tidal structures around the milky way
... in the Galactic halo at low latitudes. Under the hypothesis that stellar populations in the outer Milky Way should be more or less symmetrically distributed, two methods were used to identify asymmetries in the (l, b) distribution of 2MASS M giants that may be the signature of stellar overdensities: ...
... in the Galactic halo at low latitudes. Under the hypothesis that stellar populations in the outer Milky Way should be more or less symmetrically distributed, two methods were used to identify asymmetries in the (l, b) distribution of 2MASS M giants that may be the signature of stellar overdensities: ...
Application Exercise: Distances to Stars Using Measured Parallax
... One of the most difficult problems in astronomy is determining the distances to objects in the sky. There are four basic methods of determining distances: radar, parallax, standard candles, and the Hubble Law. Each of these methods is most useful at certain distances, with radar being useful nearby ...
... One of the most difficult problems in astronomy is determining the distances to objects in the sky. There are four basic methods of determining distances: radar, parallax, standard candles, and the Hubble Law. Each of these methods is most useful at certain distances, with radar being useful nearby ...
Science Grade 08 Unit 11 Exemplar Lesson 02: Classifying Stars
... Questions (previously distributed and affixed). 6. Project the Teacher Resource: PowerPoint: Galaxies and Stars, and discuss slides 7–9 with students. Instruct students to watch for underlined words or phrases as they continue to answer questions. Monitor students’ answers for accuracy as they compl ...
... Questions (previously distributed and affixed). 6. Project the Teacher Resource: PowerPoint: Galaxies and Stars, and discuss slides 7–9 with students. Instruct students to watch for underlined words or phrases as they continue to answer questions. Monitor students’ answers for accuracy as they compl ...
The coronal temperatures of low-mass main
... of the coronal properties of saturated stars. For example, if RX is the relevant parameter, then this would indicate that temperature scales somehow with how far a star is below the saturation threshold in rotation, given that saturation happens at a single mass-independent value of RX . It would fu ...
... of the coronal properties of saturated stars. For example, if RX is the relevant parameter, then this would indicate that temperature scales somehow with how far a star is below the saturation threshold in rotation, given that saturation happens at a single mass-independent value of RX . It would fu ...
Process of Science: PreMainSequence Stellar Life Tracks on the HR
... If you watch the position of the red dot on the HR diagram as the interactive figure plays, you will see that the dot is highest — meaning the object is most luminous— when it is a protostar and therefore does not yet have internal fusion. This fact can be a little surprising, but do not forget tha ...
... If you watch the position of the red dot on the HR diagram as the interactive figure plays, you will see that the dot is highest — meaning the object is most luminous— when it is a protostar and therefore does not yet have internal fusion. This fact can be a little surprising, but do not forget tha ...
Evolution of Population II Stars in the Helium
... on the mean molecular weight in the convective core. Hence it is very important to take into account the variation of helium content in the convective core; but its effects on the characteristics of models are not considered in the works of Hoyle and Schwarzschild1> and of Obi.?J The present work, i ...
... on the mean molecular weight in the convective core. Hence it is very important to take into account the variation of helium content in the convective core; but its effects on the characteristics of models are not considered in the works of Hoyle and Schwarzschild1> and of Obi.?J The present work, i ...
Publications 2003 - Département d`Astrophysique, Géophysique et
... the solutions best fitting the observed frequencies shows that these modes are not excited. We now study the influence of a different mixture of heavy elements. Eclipsing binary HD 92024 HD 92024 is an eclipsing binary with a Cephei primary. By combining the orbital and pulsational information from ...
... the solutions best fitting the observed frequencies shows that these modes are not excited. We now study the influence of a different mixture of heavy elements. Eclipsing binary HD 92024 HD 92024 is an eclipsing binary with a Cephei primary. By combining the orbital and pulsational information from ...
KINEMATIC DISCOVERY OF A STELLAR STREAM LOCATED IN
... In the top left and top right panels of Figure 3 we show color–magnitude diagrams (CMDs) of all stars having SDSS DR8 spectra within the on- and off-stream fields, respectively. We also show subsets of the spectra with properties expected for the PSS. The subscripts on the magnitudes g0 and (g − r)0 ...
... In the top left and top right panels of Figure 3 we show color–magnitude diagrams (CMDs) of all stars having SDSS DR8 spectra within the on- and off-stream fields, respectively. We also show subsets of the spectra with properties expected for the PSS. The subscripts on the magnitudes g0 and (g − r)0 ...
Teacher`s Guide - Cornell Science Inquiry Partnerships
... photograph or a census) and seeing what they can infer about these populations and how they change, the activity seeks to demystify the processes that astronomers and other scientists use. The same techniques can then be applied to observations of actual star clusters, allowing students to learn abo ...
... photograph or a census) and seeing what they can infer about these populations and how they change, the activity seeks to demystify the processes that astronomers and other scientists use. The same techniques can then be applied to observations of actual star clusters, allowing students to learn abo ...
Eclipsing Binary Stars as Astrophysical Laboratories
... systems. My research interests lie in observational astronomy. Students and I work at telescopes taking images and observing the stars themselves. When we look at the night sky, I think most people see it as a symbol of constancy, permanence, and eternity — never changing, always the same year after ...
... systems. My research interests lie in observational astronomy. Students and I work at telescopes taking images and observing the stars themselves. When we look at the night sky, I think most people see it as a symbol of constancy, permanence, and eternity — never changing, always the same year after ...
17_Testbank
... Chapter 17 Star Stuff 17.1 Multiple-Choice Questions 1) What do astronomers mean when they say that we are all "star stuff"? A) that life would be impossible without energy from the Sun B) that Earth formed at the same time as the Sun C) that the carbon, oxygen, and many elements essential to life w ...
... Chapter 17 Star Stuff 17.1 Multiple-Choice Questions 1) What do astronomers mean when they say that we are all "star stuff"? A) that life would be impossible without energy from the Sun B) that Earth formed at the same time as the Sun C) that the carbon, oxygen, and many elements essential to life w ...
ppt
... • An open cluster is a group of up to a few thousand stars that were formed from the same giant molecular cloud, and are still gravitationally bound to each other • Open clusters are found only in spiral and irregular galaxies, in which active star formation is occurring. • The Pleiades is an open c ...
... • An open cluster is a group of up to a few thousand stars that were formed from the same giant molecular cloud, and are still gravitationally bound to each other • Open clusters are found only in spiral and irregular galaxies, in which active star formation is occurring. • The Pleiades is an open c ...
Searching for the oldest, most metal-poor stars in the SkyMapper Survey
... the universe. Like all stars, the Population III stars performed nuclear fusion in their cores. Hydrogen atoms are fused to form helium, and helium atoms were subsequently fused to form carbon. α-elements, such as magnesium, calcium, and titanium, are made through helium capture by elements such as ...
... the universe. Like all stars, the Population III stars performed nuclear fusion in their cores. Hydrogen atoms are fused to form helium, and helium atoms were subsequently fused to form carbon. α-elements, such as magnesium, calcium, and titanium, are made through helium capture by elements such as ...
New Mass Loss Measurements from Astrospheric Lyα Absorption
... high activity levels for any type of star. Therefore, the power law in Figure 3a has been truncated at log FX p 8 # 10 5 ergs cm⫺2 s⫺1. All five of the higher activity stars have mass-loss rates much lower than the power law would suggest. The three evolved stars in Figure 3a (d Eri, l And, and DK U ...
... high activity levels for any type of star. Therefore, the power law in Figure 3a has been truncated at log FX p 8 # 10 5 ergs cm⫺2 s⫺1. All five of the higher activity stars have mass-loss rates much lower than the power law would suggest. The three evolved stars in Figure 3a (d Eri, l And, and DK U ...
Comparison of low- and high-mass star formation
... to competitive accretion. One may plausibly identify the dense filament in the early phase and the dense region at the bottom of the global gravitational potential well in the late phase as a McKee–Tan core (McKee & Tan 2003). However, the “cores” so identified are transient objects that are not in ...
... to competitive accretion. One may plausibly identify the dense filament in the early phase and the dense region at the bottom of the global gravitational potential well in the late phase as a McKee–Tan core (McKee & Tan 2003). However, the “cores” so identified are transient objects that are not in ...
Is Draco II one of the faintest dwarf galaxies? First study from Keck
... Taking the dwarf galaxy luminosity–metallicity relation of Kirby et al. (2013b) at face value, one would expect [Fe/H] ∼ −2.6 for a system of Dra II’s overall luminosity, which is compatible with our findings. In addition, only dwarf galaxies exhibit metallicity dispersions at these magnitudes (Will ...
... Taking the dwarf galaxy luminosity–metallicity relation of Kirby et al. (2013b) at face value, one would expect [Fe/H] ∼ −2.6 for a system of Dra II’s overall luminosity, which is compatible with our findings. In addition, only dwarf galaxies exhibit metallicity dispersions at these magnitudes (Will ...
sections 12-15 instructor notes
... J. C. Kapteyn, the first director of the famous Laboratory of Statistical Astronomy in Gröningen, Holland, and his successor, P. J. van Rhijn, gave us through their work in the first third of the twentieth century the basic GLF that still serves us at the present time. For the range of observable ab ...
... J. C. Kapteyn, the first director of the famous Laboratory of Statistical Astronomy in Gröningen, Holland, and his successor, P. J. van Rhijn, gave us through their work in the first third of the twentieth century the basic GLF that still serves us at the present time. For the range of observable ab ...
Lecture 14
... satellites into space to measure very precise parallax? • Would it be easier to measure parallax from Jupiter? From Venus? ...
... satellites into space to measure very precise parallax? • Would it be easier to measure parallax from Jupiter? From Venus? ...
Star
A star is a luminous sphere of plasma held together by its own gravity. The nearest star to Earth is the Sun. Other stars are visible from Earth during the night, appearing as a multitude of fixed luminous points in the sky due to their immense distance from Earth. Historically, the most prominent stars were grouped into constellations and asterisms, and the brightest stars gained proper names. Extensive catalogues of stars have been assembled by astronomers, which provide standardized star designations.For at least a portion of its life, a star shines due to thermonuclear fusion of hydrogen into helium in its core, releasing energy that traverses the star's interior and then radiates into outer space. Once the hydrogen in the core of a star is nearly exhausted, almost all naturally occurring elements heavier than helium are created by stellar nucleosynthesis during the star's lifetime and, for some stars, by supernova nucleosynthesis when it explodes. Near the end of its life, a star can also contain degenerate matter. Astronomers can determine the mass, age, metallicity (chemical composition), and many other properties of a star by observing its motion through space, luminosity, and spectrum respectively. The total mass of a star is the principal determinant of its evolution and eventual fate. Other characteristics of a star, including diameter and temperature, change over its life, while the star's environment affects its rotation and movement. A plot of the temperature of many stars against their luminosities, known as a Hertzsprung–Russell diagram (H–R diagram), allows the age and evolutionary state of a star to be determined.A star's life begins with the gravitational collapse of a gaseous nebula of material composed primarily of hydrogen, along with helium and trace amounts of heavier elements. Once the stellar core is sufficiently dense, hydrogen becomes steadily converted into helium through nuclear fusion, releasing energy in the process. The remainder of the star's interior carries energy away from the core through a combination of radiative and convective processes. The star's internal pressure prevents it from collapsing further under its own gravity. Once the hydrogen fuel at the core is exhausted, a star with at least 0.4 times the mass of the Sun expands to become a red giant, in some cases fusing heavier elements at the core or in shells around the core. The star then evolves into a degenerate form, recycling a portion of its matter into the interstellar environment, where it will contribute to the formation of a new generation of stars with a higher proportion of heavy elements. Meanwhile, the core becomes a stellar remnant: a white dwarf, a neutron star, or (if it is sufficiently massive) a black hole.Binary and multi-star systems consist of two or more stars that are gravitationally bound, and generally move around each other in stable orbits. When two such stars have a relatively close orbit, their gravitational interaction can have a significant impact on their evolution. Stars can form part of a much larger gravitationally bound structure, such as a star cluster or a galaxy.