ted_2012_power_of_design
... positively charged protons (diameter 1.6−1.7 fm) reside in each atomic nucleus—this equaling the atomic number. Slightly heavier than protons, neutrons have no charge. Hydrogen aside (having one proton), atomic nuclei consist of two or more protons and various numbers of neutrons. While we begin at ...
... positively charged protons (diameter 1.6−1.7 fm) reside in each atomic nucleus—this equaling the atomic number. Slightly heavier than protons, neutrons have no charge. Hydrogen aside (having one proton), atomic nuclei consist of two or more protons and various numbers of neutrons. While we begin at ...
Widener University
... A star has mass 2.5 Msun = 5.0 x 1030 kg, radius 2.0 Rsun = 1.4 x 109 m, and luminosity 40 Lsun = 1.6 x 1028 W. The star is initially composed of 100% H and converts all of it to He, each chain of 4H He releasing an amount of energy E = 4.3 x 10-12 J. Calculate: a) the total number of H nuclei (p ...
... A star has mass 2.5 Msun = 5.0 x 1030 kg, radius 2.0 Rsun = 1.4 x 109 m, and luminosity 40 Lsun = 1.6 x 1028 W. The star is initially composed of 100% H and converts all of it to He, each chain of 4H He releasing an amount of energy E = 4.3 x 10-12 J. Calculate: a) the total number of H nuclei (p ...
–1– 2. Milky Way We know a great deal, perhaps more than any
... Kapteyn was aware of extinction problems. He searched for these, but did not find any significant effect. However, the mistake he made was at that time he was only aware of scattering by dust particles, but he did not consider absorption, which turns out to have a much more important effect. • Shapl ...
... Kapteyn was aware of extinction problems. He searched for these, but did not find any significant effect. However, the mistake he made was at that time he was only aware of scattering by dust particles, but he did not consider absorption, which turns out to have a much more important effect. • Shapl ...
10 Astrophysics (Option E)
... Before techniques had been invented for measuring brightness, it was estimated with the naked eye on a scale from 1 to 6. The brightest stars were 1 and the ones that you could only just see were 6. This would be dependent on how good your eyesight was. ...
... Before techniques had been invented for measuring brightness, it was estimated with the naked eye on a scale from 1 to 6. The brightest stars were 1 and the ones that you could only just see were 6. This would be dependent on how good your eyesight was. ...
31-2 - Fremont Peak Observatory
... object was understood. Thus, in at least two cases that will be sited, the name was inappropriate. In one case, we still use a description coined in the 1700’s. In another case, the designation was so wrong that the term has been replaced. A nebula is an area of diffuse gas or dust. But from there t ...
... object was understood. Thus, in at least two cases that will be sited, the name was inappropriate. In one case, we still use a description coined in the 1700’s. In another case, the designation was so wrong that the term has been replaced. A nebula is an area of diffuse gas or dust. But from there t ...
The Bigger Picture - Astronomy and Astrophysics
... • Imagine a star with a relatively cool (4000k) atmosphere. Temperature is just a measure of the average velocity of the atoms and molecules in a gas. For a relatively cool gas there are: (1) Few atomic collisions with enough energy to knock electrons up to the 1st excited state so the majority of t ...
... • Imagine a star with a relatively cool (4000k) atmosphere. Temperature is just a measure of the average velocity of the atoms and molecules in a gas. For a relatively cool gas there are: (1) Few atomic collisions with enough energy to knock electrons up to the 1st excited state so the majority of t ...
Open access - ORBi
... • the dusty and non-dusty sub-samples have the same number of stars, are spread similarly between the various spectral types, and have similar median magnitudes; • the sample is evenly spread between spectral types A, F and G-K, if possible with similar mean magnitudes. Based on these requirements, ...
... • the dusty and non-dusty sub-samples have the same number of stars, are spread similarly between the various spectral types, and have similar median magnitudes; • the sample is evenly spread between spectral types A, F and G-K, if possible with similar mean magnitudes. Based on these requirements, ...
PH607lec12
... more and more galaxies at larger distances have been observed. We live in an expanding Universe. Due to the Big Bang, the Universe is expanding. Hubble found that there was a direct linear relation between distance and redshift: the further a galaxy was from us, the faster its recession velocity. Th ...
... more and more galaxies at larger distances have been observed. We live in an expanding Universe. Due to the Big Bang, the Universe is expanding. Hubble found that there was a direct linear relation between distance and redshift: the further a galaxy was from us, the faster its recession velocity. Th ...
Cepheid
... In Shapley’s day, the LMC and SMC were considered as two isolated offshoots of the Milky Way, different from the spiral nebulae. We now realize that they are ‘dwarf’ galaxies in their own right (but not spirals). ...
... In Shapley’s day, the LMC and SMC were considered as two isolated offshoots of the Milky Way, different from the spiral nebulae. We now realize that they are ‘dwarf’ galaxies in their own right (but not spirals). ...
HR Diagram
... In addition to the isoradius lines, check show luminosity classes. This green region (dwarfs V) is known as the main sequence and contains all stars that are fusing hydrogen into helium as their primary energy source. Over 90% of all stars fall in this region on the HR diagram. Move the active curso ...
... In addition to the isoradius lines, check show luminosity classes. This green region (dwarfs V) is known as the main sequence and contains all stars that are fusing hydrogen into helium as their primary energy source. Over 90% of all stars fall in this region on the HR diagram. Move the active curso ...
Deriving the Isoradius Lines (optional, mathematical
... Uncheck show luminosity classes and check show instability strip. Note that this region of the HR Diagram indicates where pulsating stars are found such as RR Lyrae stars and Cepheid variable stars. These stars vary in brightness because they are pulsating – alternately growing bigger and smaller – ...
... Uncheck show luminosity classes and check show instability strip. Note that this region of the HR Diagram indicates where pulsating stars are found such as RR Lyrae stars and Cepheid variable stars. These stars vary in brightness because they are pulsating – alternately growing bigger and smaller – ...
Word version of Episode 704
... The Andromeda galaxy M31 can just, but only just, be seen with the naked eye. Its light, 2 million years old, is the oldest light you can see with the unaided eye. The Andromeda galaxy, M31, is the nearest neighbour large galaxy to our own Galaxy, the Milky Way. It is about 2.2 million light years a ...
... The Andromeda galaxy M31 can just, but only just, be seen with the naked eye. Its light, 2 million years old, is the oldest light you can see with the unaided eye. The Andromeda galaxy, M31, is the nearest neighbour large galaxy to our own Galaxy, the Milky Way. It is about 2.2 million light years a ...
Age Estimates of Globular Clusters in the Milky Way
... The statistical parallax techfound in Fig. 2 and its caption. nique yields values for Mv(RR) The key to the success of this that are larger (i.e., fainter) than approach involves the accuracy in the other distance techniques. determining the intrinsic lumiWhen statistical parallax results nosity of ...
... The statistical parallax techfound in Fig. 2 and its caption. nique yields values for Mv(RR) The key to the success of this that are larger (i.e., fainter) than approach involves the accuracy in the other distance techniques. determining the intrinsic lumiWhen statistical parallax results nosity of ...
Starbursts – from 30 Doradus to Lyman
... in addition, appear to be continuous across a range of amplitudes – and redshifts – suggesting a galaxy classification sequence similar to the Hubble tuning fork, but now from M82-like starbursts via ultraluminous infrared galaxies to the recently discovered SCUBA galaxies, as well as from Lyman-bre ...
... in addition, appear to be continuous across a range of amplitudes – and redshifts – suggesting a galaxy classification sequence similar to the Hubble tuning fork, but now from M82-like starbursts via ultraluminous infrared galaxies to the recently discovered SCUBA galaxies, as well as from Lyman-bre ...
Lecture 2
... Ellipticals are classified according to their shape from E0 (almost spherical) to E7 (the most elongated). Which class depends on angle; E0 can look like E7 if seen “edge-on”. ...
... Ellipticals are classified according to their shape from E0 (almost spherical) to E7 (the most elongated). Which class depends on angle; E0 can look like E7 if seen “edge-on”. ...
It is now recognized that the vast majority of ellipticals are of
... • Cores may exhibit unusual kinematics; for example, about a quarter of all elliptical galaxies have cores which appear to counter-rotate with respect to the rest of the galaxy . • A few nearby E galaxies have nuclear star clusters with densities much higher than the cores they reside in; some of th ...
... • Cores may exhibit unusual kinematics; for example, about a quarter of all elliptical galaxies have cores which appear to counter-rotate with respect to the rest of the galaxy . • A few nearby E galaxies have nuclear star clusters with densities much higher than the cores they reside in; some of th ...
Understanding the H-R Diagram
... formed and by its evolutionary stage (its "growth" stage). In general, the more massive a star is, the hottest its surface." 1 In other words, how hot, how luminous and which stages a star will go through and eventually become (its life span) is dependent upon the star's original mass at the time of ...
... formed and by its evolutionary stage (its "growth" stage). In general, the more massive a star is, the hottest its surface." 1 In other words, how hot, how luminous and which stages a star will go through and eventually become (its life span) is dependent upon the star's original mass at the time of ...
San Pedro Mártir observations of microvariability in obscured quasars
... which rises the question whether microvariations can also be detected in obscured AGNs in the optical regime. Because the expected variations are very small and can easily be lost within the noise, the analysis requires a statistical approach. We report the use of a one-way analysis of variance, ANO ...
... which rises the question whether microvariations can also be detected in obscured AGNs in the optical regime. Because the expected variations are very small and can easily be lost within the noise, the analysis requires a statistical approach. We report the use of a one-way analysis of variance, ANO ...
JWST_eye - University of Arizona
... and Rigel in Orion have much different colors. The color of Betelgeuse is ________. The color of Rigel is ________. The color of stars in the Pleiades is ______. JWST is designed to sense “infrared” colors of light about 3-30 times redder than the limit of the human eye. Infrared light penetrates in ...
... and Rigel in Orion have much different colors. The color of Betelgeuse is ________. The color of Rigel is ________. The color of stars in the Pleiades is ______. JWST is designed to sense “infrared” colors of light about 3-30 times redder than the limit of the human eye. Infrared light penetrates in ...
White dwarf cooling sequences and cosmochronology
... uniformity of the models with log(L/L ) ≤ −1.5. Furthermore, since the time necessary to reach this value is ≤ 8 × 107 years for any model, its influence in the total cooling time is negligible [19], except of course at large luminosities. Fluid cooling: This phase occurs at luminosities −1.5 ≥ log ...
... uniformity of the models with log(L/L ) ≤ −1.5. Furthermore, since the time necessary to reach this value is ≤ 8 × 107 years for any model, its influence in the total cooling time is negligible [19], except of course at large luminosities. Fluid cooling: This phase occurs at luminosities −1.5 ≥ log ...
Comments
... We address the origin of the robust bi-modality in galaxies about a critical stellar mass ~3x10^10 Msol. Less massive galaxies tend to be ungrouped blue star-forming discs correlated along a fundamental line. More massive galaxies are typically grouped red oldstar spheroids on a fundamental plane ho ...
... We address the origin of the robust bi-modality in galaxies about a critical stellar mass ~3x10^10 Msol. Less massive galaxies tend to be ungrouped blue star-forming discs correlated along a fundamental line. More massive galaxies are typically grouped red oldstar spheroids on a fundamental plane ho ...
Here
... • We can measure the temperature of a star relatively easily by its spectral type or color. If the distance is known, then we can measure its luminosity, and then compute its radius. Note, however, that the radius measured this way is not very accurate, owing to the uncertainty in the distance. • Is ...
... • We can measure the temperature of a star relatively easily by its spectral type or color. If the distance is known, then we can measure its luminosity, and then compute its radius. Note, however, that the radius measured this way is not very accurate, owing to the uncertainty in the distance. • Is ...
Lab PDF - NMSU Astronomy
... Astronomers describe the brightness of stars in two different ways: apparent brightness, based on how bright an object looks to us here on Earth, and intrinsic brightness (or luminosity), based on how bright an object actually is, independent of how far away it lies from a viewer. We have devised a ...
... Astronomers describe the brightness of stars in two different ways: apparent brightness, based on how bright an object looks to us here on Earth, and intrinsic brightness (or luminosity), based on how bright an object actually is, independent of how far away it lies from a viewer. We have devised a ...
PDF format
... a) They are useful in measuring the distances of other galaxies. b) Their variability enables us to determine their masses. c) Their variability enables us to determine their rotation rates. d) They are useful in studying sunspots on other stars. e) They are useful in understanding stellar flar ...
... a) They are useful in measuring the distances of other galaxies. b) Their variability enables us to determine their masses. c) Their variability enables us to determine their rotation rates. d) They are useful in studying sunspots on other stars. e) They are useful in understanding stellar flar ...
There are billions of galaxies, many containing
... brightness allows us to determine its distance. The farther it is from the sun, the dimmer it will appear. If we know any two of the three—absolute brightness, apparent brightness, and distance—we can compute the third, distance in this case. It is simply a matter of geometry. Distances to galaxies ...
... brightness allows us to determine its distance. The farther it is from the sun, the dimmer it will appear. If we know any two of the three—absolute brightness, apparent brightness, and distance—we can compute the third, distance in this case. It is simply a matter of geometry. Distances to galaxies ...
Malmquist bias
The Malmquist bias is an effect in observational astronomy which leads to the preferential detection of intrinsically bright objects. It was first described in 1922 by Swedish astronomer Gunnar Malmquist (1893–1982), who then greatly elaborated upon this work in 1925. In statistics, this bias is referred to as a selection bias and affects the survey results in a brightness limited survey, where stars below a certain apparent brightness are not included. Since observed stars and galaxies appear dimmer when farther away, the brightness that is measured will fall off with distance until their brightness falls below the observational threshold. Objects which are more luminous, or intrinsically brighter, can be observed at a greater distance, creating a false trend of increasing intrinsic brightness, and other related quantities, with distance. This effect has led to many spurious claims in the field of astronomy. Properly correcting for these effects has become an area of great focus.