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Institute for Astrophysical Research Seminar Series
... Steven Snowden (NASA Goddard Space Flight Center) The Diffuse X-ray Background, from Earth's Exosphere to the Edge of the Universe OR One Astronomer's Signal is Another Astronomer's Contamination ...
... Steven Snowden (NASA Goddard Space Flight Center) The Diffuse X-ray Background, from Earth's Exosphere to the Edge of the Universe OR One Astronomer's Signal is Another Astronomer's Contamination ...
15_Testbank
... 11) A 10-solar-mass star is about ten times more luminous than a 1-solar-mass star. Answer: FALSE 12) Most stars on the main sequence fuse hydrogen into helium in their cores, but some do not. Answer: FALSE 13) All stars spend approximately the same amount of time on the main sequence. Answer: FALS ...
... 11) A 10-solar-mass star is about ten times more luminous than a 1-solar-mass star. Answer: FALSE 12) Most stars on the main sequence fuse hydrogen into helium in their cores, but some do not. Answer: FALSE 13) All stars spend approximately the same amount of time on the main sequence. Answer: FALS ...
The Interstellar Medium
... 20. The best vacuum chambers on Earth can reach densities of about 1,000,000 atoms per cubic centimeter. Which of the four components of the interstellar medium has lower densities than such a chamber? a. The hot coronal gas. b. The hot coronal gas and HII intercloud medium. c. The hot coronal gas, ...
... 20. The best vacuum chambers on Earth can reach densities of about 1,000,000 atoms per cubic centimeter. Which of the four components of the interstellar medium has lower densities than such a chamber? a. The hot coronal gas. b. The hot coronal gas and HII intercloud medium. c. The hot coronal gas, ...
The Young Stars
... lines in emission, but with an Hα equivalent width under 10 Å (the equivalent width is the width the line would have on supposing the line emission peaks at the same level as the stellar continuum). In 1978, George Herbig described them as post T Tauri stars, having finished their formation and now ...
... lines in emission, but with an Hα equivalent width under 10 Å (the equivalent width is the width the line would have on supposing the line emission peaks at the same level as the stellar continuum). In 1978, George Herbig described them as post T Tauri stars, having finished their formation and now ...
The star formation histories of two northern LMC fields
... the star formation rate in these fields, beginning approximately 2.5 Gyr ago, with the current metallicity in the region being Fe=H 20:38 ^ 0:10: The two fields have had very similar star formation rates until 200 Myr ago, at which point one shows a large increase. Key words: Magellanic Clouds ± ...
... the star formation rate in these fields, beginning approximately 2.5 Gyr ago, with the current metallicity in the region being Fe=H 20:38 ^ 0:10: The two fields have had very similar star formation rates until 200 Myr ago, at which point one shows a large increase. Key words: Magellanic Clouds ± ...
Star formation in galaxies over the last 10 billion
... Astronomers can look back in time: light from very distant galaxies took billions of years to reach us. Looking far is looking back ...
... Astronomers can look back in time: light from very distant galaxies took billions of years to reach us. Looking far is looking back ...
neutron star
... “SURFACE” OF A BLACK HOLE • The “surface” of a black hole is the radius at which the escape velocity equals the speed of light. • This spherical surface is known as the event horizon. • The radius of the event horizon is known as the ...
... “SURFACE” OF A BLACK HOLE • The “surface” of a black hole is the radius at which the escape velocity equals the speed of light. • This spherical surface is known as the event horizon. • The radius of the event horizon is known as the ...
Solution
... the red one must be smaller. But by Stefan-Boltzmann's Law, its luminosity/area must also be smaller, and they are the same size. So the red one is less luminous. 3. ( T F ) Using parallax, astronomers can now reliably measure the distance of most of the stars in our galaxy. False. Sad to say, most ...
... the red one must be smaller. But by Stefan-Boltzmann's Law, its luminosity/area must also be smaller, and they are the same size. So the red one is less luminous. 3. ( T F ) Using parallax, astronomers can now reliably measure the distance of most of the stars in our galaxy. False. Sad to say, most ...
Thu th surf c
... Thus the surface facing us periodically approaches and recedes from us, thereby causing the spectral lines to shift periodically to the blue and to the red. When we plot a Cepheid's variations in velocity against time we obtain a velocity curve for the star. ...
... Thus the surface facing us periodically approaches and recedes from us, thereby causing the spectral lines to shift periodically to the blue and to the red. When we plot a Cepheid's variations in velocity against time we obtain a velocity curve for the star. ...
Clusters: age scales for stellar physics
... In order to define an age scale (or several), it is very important to keep in mind that we cannot make experiments except in very few situations and we rely on observations and theory. Thus, observational phenomena with very well defined ages, our anchors, are extremely important. As a matter of fac ...
... In order to define an age scale (or several), it is very important to keep in mind that we cannot make experiments except in very few situations and we rely on observations and theory. Thus, observational phenomena with very well defined ages, our anchors, are extremely important. As a matter of fac ...
Rotation, activity, and stellar obliquities in a large uniform sample of
... stars which are like the Sun and thus might shed light on characteristics of its composition, structure, activity, planetary system, evolution, and future. Solar analogs are useful in many ways, ranging from finding night-time proxies for the Sun for calibration purposes to their use as snapshots of ...
... stars which are like the Sun and thus might shed light on characteristics of its composition, structure, activity, planetary system, evolution, and future. Solar analogs are useful in many ways, ranging from finding night-time proxies for the Sun for calibration purposes to their use as snapshots of ...
Which planet has never been orbited or flown past by a
... Zeilik, M., Schau, C., & Mattern, N. 1999, Conceptual Astronomy. II. Replicating Conceptual Gains, Probing Attitude Changes Across Three Semesters, American Journal of Physics, 67(10), 923. Zeilik, M., Schau, C., Mattern, N., Hall, S., Teague, K. W., & Bisard, W. J. 1997, Conceptual Astronomy: A Nov ...
... Zeilik, M., Schau, C., & Mattern, N. 1999, Conceptual Astronomy. II. Replicating Conceptual Gains, Probing Attitude Changes Across Three Semesters, American Journal of Physics, 67(10), 923. Zeilik, M., Schau, C., Mattern, N., Hall, S., Teague, K. W., & Bisard, W. J. 1997, Conceptual Astronomy: A Nov ...
83-98
... Wielen (1974) for the cepheids farther than 1 kpc. For distant Cepheids like RS Pup, WZ Sgr, Τ Mon, X Cyg etc. which are young, the birthsites were calculated by Wielen (1973) assuming the space velocity components to be zero. However, the space velocity components are calculated by Giridhar (1986) ...
... Wielen (1974) for the cepheids farther than 1 kpc. For distant Cepheids like RS Pup, WZ Sgr, Τ Mon, X Cyg etc. which are young, the birthsites were calculated by Wielen (1973) assuming the space velocity components to be zero. However, the space velocity components are calculated by Giridhar (1986) ...
Chemical analysis of 24 dusty (pre-) main
... of CNO lines and the non-LTE (local thermodynamic equilibrium) sensitivity of especially nitrogen implies that the uncertainties on the CNO abundances are sometimes critical for assessing whether selective depletion occurs; in all cases at most a few lines are available for the determination of the ...
... of CNO lines and the non-LTE (local thermodynamic equilibrium) sensitivity of especially nitrogen implies that the uncertainties on the CNO abundances are sometimes critical for assessing whether selective depletion occurs; in all cases at most a few lines are available for the determination of the ...
uv surface environment of earth-like planets orbiting
... We focus on four geological epochs from Earth’s history to model the UV environment on the surface of an Earth-like planet at the 1 AU equivalent distance from its host star. The geological evidence from 2.8–3.5 Ga is consistent with an atmosphere with similar atmospheric pressure as modern Earth (S ...
... We focus on four geological epochs from Earth’s history to model the UV environment on the surface of an Earth-like planet at the 1 AU equivalent distance from its host star. The geological evidence from 2.8–3.5 Ga is consistent with an atmosphere with similar atmospheric pressure as modern Earth (S ...
Spectroscopic Variability of Supergiant Star HD14134, B3Ia
... typical for hot supergiants such as HD14134, apart from Hα, are observed, including Hβ. In order to investigate the short term variability in the Hα profile, all individual spectra obtained on December 29-30, 2013, and on February 13, 15, 2016 were processed separately. These data are presented in Fi ...
... typical for hot supergiants such as HD14134, apart from Hα, are observed, including Hβ. In order to investigate the short term variability in the Hα profile, all individual spectra obtained on December 29-30, 2013, and on February 13, 15, 2016 were processed separately. These data are presented in Fi ...
Spectroscopic Variability of Supergiant Star HD14134, B3Ia
... typical for hot supergiants such as HD14134, apart from Hα, are observed, including Hβ. In order to investigate the short term variability in the Hα profile, all individual spectra obtained on December 29-30, 2013, and on February 13, 15, 2016 were processed separately. These data are presented in Fi ...
... typical for hot supergiants such as HD14134, apart from Hα, are observed, including Hβ. In order to investigate the short term variability in the Hα profile, all individual spectra obtained on December 29-30, 2013, and on February 13, 15, 2016 were processed separately. These data are presented in Fi ...
Stellar kinematics
Stellar kinematics is the study of the movement of stars without needing to understand how they acquired their motion. This differs from stellar dynamics, which takes into account gravitational effects. The motion of a star relative to the Sun can provide useful information about the origin and age of a star, as well as the structure and evolution of the surrounding part of the Milky Way.In astronomy, it is widely accepted that most stars are born within molecular clouds known as stellar nurseries. The stars formed within such a cloud compose open clusters containing dozens to thousands of members. These clusters dissociate over time. Stars that separate themselves from the cluster's core are designated as members of the cluster's stellar association. If the remnant later drifts through the Milky Way as a coherent assemblage, then it is termed a moving group.