docx - STAO
... colour) and the distance from the observer. Sometimes the brightest-looking stars are not actually the brightest, and sometimes the closest-looking stars are not the closest. Light energy dissipates (spreads out) as it travels from its source. You could briefly discuss the idea of the inverse square ...
... colour) and the distance from the observer. Sometimes the brightest-looking stars are not actually the brightest, and sometimes the closest-looking stars are not the closest. Light energy dissipates (spreads out) as it travels from its source. You could briefly discuss the idea of the inverse square ...
Document
... For stars like the sun, the oscillation period is 5 min → 1 min exposure time For good RV measurement you need S/N = 200 On a 2m telescope with a good spectrograph you can get S/N = 100 (10000 photons) in one hour on a V=10 star → 400.000 photons on a V=6 star in one hour, 6600 photons in one minute ...
... For stars like the sun, the oscillation period is 5 min → 1 min exposure time For good RV measurement you need S/N = 200 On a 2m telescope with a good spectrograph you can get S/N = 100 (10000 photons) in one hour on a V=10 star → 400.000 photons on a V=6 star in one hour, 6600 photons in one minute ...
Lecture19
... All stars: As H is burned up in core, it leaves behind He “ash”. When H is used up, core begins contracting, and H is burned in a shell around the core. Star’s outer layers expand, cooling and getting much brighter, becoming a Red Giant star. Eventually core contracts enough to become so hot it can ...
... All stars: As H is burned up in core, it leaves behind He “ash”. When H is used up, core begins contracting, and H is burned in a shell around the core. Star’s outer layers expand, cooling and getting much brighter, becoming a Red Giant star. Eventually core contracts enough to become so hot it can ...
Teacher Demo: Bright Star or Close Star?
... colour) and the distance from the observer. Sometimes the brightest-looking stars are not actually the brightest, and sometimes the closest-looking stars are not the closest. Light energy dissipates (spreads out) as it travels from its source. You could briefly discuss the idea of the inverse square ...
... colour) and the distance from the observer. Sometimes the brightest-looking stars are not actually the brightest, and sometimes the closest-looking stars are not the closest. Light energy dissipates (spreads out) as it travels from its source. You could briefly discuss the idea of the inverse square ...
Astronomical Distance Ladder
... fairly simple using the standard candle approach. Both types of cepheid variable stars are pulsating stars whose period and luminosity are dependent on the mass of the star. Thus at specific periods every cepheid of one type has the same luminosity. The standard candles approach can be used for supe ...
... fairly simple using the standard candle approach. Both types of cepheid variable stars are pulsating stars whose period and luminosity are dependent on the mass of the star. Thus at specific periods every cepheid of one type has the same luminosity. The standard candles approach can be used for supe ...
Populations of Galaxies and their Formation at z < 7
... integrated stellar mass in the universe increases gradually throughout this time suggesting that galaxy formation does not happen all at once. 3. Galaxies at high redshifts are peculiar and are likely undergoing mergers. The transition from mergers to normal Hubble types occurs at about z~1.5. Calcu ...
... integrated stellar mass in the universe increases gradually throughout this time suggesting that galaxy formation does not happen all at once. 3. Galaxies at high redshifts are peculiar and are likely undergoing mergers. The transition from mergers to normal Hubble types occurs at about z~1.5. Calcu ...
GRADE 12A: Physics 7
... Point out that parallax measurements can only be used for relatively nearby stars (closer than about 100 pc). For more distant stars, less direct methods must be used. Explain how the HR diagram can be used in the following ways to estimate distances of stars. • Single star. Deduce the star’s temper ...
... Point out that parallax measurements can only be used for relatively nearby stars (closer than about 100 pc). For more distant stars, less direct methods must be used. Explain how the HR diagram can be used in the following ways to estimate distances of stars. • Single star. Deduce the star’s temper ...
Exercises
... ii. Calculate the fractional amount of mass converted into energy by hydrogen fusion. (Refer to Table 1 for the mass of a proton and of a helium nucleus.) iii. Derive an expression for the nuclear timescale in solar units, i.e. expressed in terms of R/R , M/M and L/L . iv. Use the mass-radius and ...
... ii. Calculate the fractional amount of mass converted into energy by hydrogen fusion. (Refer to Table 1 for the mass of a proton and of a helium nucleus.) iii. Derive an expression for the nuclear timescale in solar units, i.e. expressed in terms of R/R , M/M and L/L . iv. Use the mass-radius and ...
LIFE CYCLE OF STARS
... Planetary Nebula-a shell of gas discarded by a medium star white dwarf-A star that has exhausted most or all of its nuclear fuel and has collapsed to a very ...
... Planetary Nebula-a shell of gas discarded by a medium star white dwarf-A star that has exhausted most or all of its nuclear fuel and has collapsed to a very ...
The masses of stars
... brightness (stars shine with luminosities that are tens of thousands of times fainter and over a million times brighter than our Sun); of surface temperature (from below 3,000K to greater than 30,000K); of size (with diameters of about ten km for neutron stars, about 1.4 million km for our Sun, and ...
... brightness (stars shine with luminosities that are tens of thousands of times fainter and over a million times brighter than our Sun); of surface temperature (from below 3,000K to greater than 30,000K); of size (with diameters of about ten km for neutron stars, about 1.4 million km for our Sun, and ...
ORBITAL MOTION
... Abundance gradient. Inner solar system is poor in light volatile gases such as H, He, but rich in Fe & Ni. Outer solar system is rich in volatiles H, He, etc. Abundances similar to that of the sun. ...
... Abundance gradient. Inner solar system is poor in light volatile gases such as H, He, but rich in Fe & Ni. Outer solar system is rich in volatiles H, He, etc. Abundances similar to that of the sun. ...
Double Stars in Scorpio`s Claws
... stars that are a rewarding challenge to any astronomer. Some of these are actual double stars (pairs of stars that orbit about each other), others are ‘apparent doubles’ – stars that simply lie along the same line of sight, but are very distant from each other in space. The map below indicates the l ...
... stars that are a rewarding challenge to any astronomer. Some of these are actual double stars (pairs of stars that orbit about each other), others are ‘apparent doubles’ – stars that simply lie along the same line of sight, but are very distant from each other in space. The map below indicates the l ...
Galaxy alignment within dark matter halos
... strength is well consistent with observational results. The dependence of alignment on satellite color is consistent with observational results. However, due to the wrong color for central galaxies, the predicted alignment for centrals is wrong. If the color of central galaxies is defined by h ...
... strength is well consistent with observational results. The dependence of alignment on satellite color is consistent with observational results. However, due to the wrong color for central galaxies, the predicted alignment for centrals is wrong. If the color of central galaxies is defined by h ...
Does Transparent Hidden Matter Generate Optical Scintillation?
... • Gas at ~10pc Scintillation would also occur on the biggest stars ...
... • Gas at ~10pc Scintillation would also occur on the biggest stars ...
PH607lec08
... needed for distances of this order. Can also define a Hubble time: 1 / H0 ~ 1010 years …this is to order of magnitude the age of the Universe. But there is sufficient mass in the Universe which slows down the expansion - so our assumption that, for example, M87 and the Galaxy have been moving apart ...
... needed for distances of this order. Can also define a Hubble time: 1 / H0 ~ 1010 years …this is to order of magnitude the age of the Universe. But there is sufficient mass in the Universe which slows down the expansion - so our assumption that, for example, M87 and the Galaxy have been moving apart ...
Date_________________ TWINKLE, TWINKLE
... The first property is absolute magnitude (M) which is how bright a star would appear if it was at a fixed distance away from the Earth1. This is a calculated value and removes distance as a concern when we compare stars. The only thing that affects absolute magnitude is the natural intensity of the ...
... The first property is absolute magnitude (M) which is how bright a star would appear if it was at a fixed distance away from the Earth1. This is a calculated value and removes distance as a concern when we compare stars. The only thing that affects absolute magnitude is the natural intensity of the ...
Stellar Evolution
... Leads to a very different fate Path across the H-R diagram is essentially a straight line Stays at just about the same luminosity as it cools off Eventually the star dies in a violent explosion called a supernova ...
... Leads to a very different fate Path across the H-R diagram is essentially a straight line Stays at just about the same luminosity as it cools off Eventually the star dies in a violent explosion called a supernova ...
Stars part 2
... By the end of this presentation, students will be able to • explain the role of nuclear fusion in the sun’s core to release energy; • communicate scientific ideas about the way stars, over their life cycle, produce elements; • illustrate the life span of the sun. ...
... By the end of this presentation, students will be able to • explain the role of nuclear fusion in the sun’s core to release energy; • communicate scientific ideas about the way stars, over their life cycle, produce elements; • illustrate the life span of the sun. ...
The Search for the Earliest Galaxies
... These galaxies are at the earliest stage of development ever seen. They appear clumpy, not yet having developed into the familiar spiral or elliptical shapes seen in the nearby universe. They are also very compact, only one-twentieth the size of the Milky Way galaxy, and possess only one-hundreth of ...
... These galaxies are at the earliest stage of development ever seen. They appear clumpy, not yet having developed into the familiar spiral or elliptical shapes seen in the nearby universe. They are also very compact, only one-twentieth the size of the Milky Way galaxy, and possess only one-hundreth of ...
PH607lec12
... distances and also that what Hubble thought were bright stars in distant galaxies were actually H II regions. Throughout the 20th century we found evidence for H in the range 50 -100 km/s/Mpc, depending on the method employed. So, we took h = H/100 km/s/Mpc in all our formula to parameterize our ign ...
... distances and also that what Hubble thought were bright stars in distant galaxies were actually H II regions. Throughout the 20th century we found evidence for H in the range 50 -100 km/s/Mpc, depending on the method employed. So, we took h = H/100 km/s/Mpc in all our formula to parameterize our ign ...
Chapter 13 (Properties of Stars)
... 24. The largest known stars. 25. Most low mass, red stars in our neighborhood. 26. Sirius B, the hot white dwarf only 1/1000th as luminous as the sun. 27. The vast majority of bright blue naked eye stars. 28. Most naked eye stars that appear red or orange in color. 29. The most massive young stars. ...
... 24. The largest known stars. 25. Most low mass, red stars in our neighborhood. 26. Sirius B, the hot white dwarf only 1/1000th as luminous as the sun. 27. The vast majority of bright blue naked eye stars. 28. Most naked eye stars that appear red or orange in color. 29. The most massive young stars. ...
Assignment 3 - Physics Internal Website
... gas nebulae (HII regions), as they are the brightest objects in optical spectra. Most of the emission from stars are continuum in nature. The emission originates from the hot, opaque interiors of the star. As it leaves the star it passes through a more diffuse, transparent stellar atmosphere, which ...
... gas nebulae (HII regions), as they are the brightest objects in optical spectra. Most of the emission from stars are continuum in nature. The emission originates from the hot, opaque interiors of the star. As it leaves the star it passes through a more diffuse, transparent stellar atmosphere, which ...
Cartwheel Galaxy - Chandra X
... superimposed with high resolution radio observations of neutral hydrogen (traced by the green contours). The neutral hydrogen trail suggests that the intruder galaxy could be the galaxy located at the lower left of the image. ...
... superimposed with high resolution radio observations of neutral hydrogen (traced by the green contours). The neutral hydrogen trail suggests that the intruder galaxy could be the galaxy located at the lower left of the image. ...
12.1 Introduction
... Particularly useful in this respect are the H-R diagrams of halo globular clusters which, being among the oldest stellar systems known, give us a view of the late stages in the evolution of long-lived stars with masses comparable to that of the Sun (see Figure 12.3). The combination of computer mode ...
... Particularly useful in this respect are the H-R diagrams of halo globular clusters which, being among the oldest stellar systems known, give us a view of the late stages in the evolution of long-lived stars with masses comparable to that of the Sun (see Figure 12.3). The combination of computer mode ...
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.