astrocoursespring2012lec4
... Using modern telescopes and computers, astronomers have studied numerous properties of globular clusters. Here are just some of the quantities that we can measure for globular clusters: •size (radius), •mass, •distance from galactic center, •distance from Earth, •brightness, •age ** ...
... Using modern telescopes and computers, astronomers have studied numerous properties of globular clusters. Here are just some of the quantities that we can measure for globular clusters: •size (radius), •mass, •distance from galactic center, •distance from Earth, •brightness, •age ** ...
Document
... • We define our age by trips around the Sun. • How many trips of Sun around Milky Way? R = 8.5 kpc V = 220km/s P = 2.5x108 yrs ...
... • We define our age by trips around the Sun. • How many trips of Sun around Milky Way? R = 8.5 kpc V = 220km/s P = 2.5x108 yrs ...
Gemini
... corresponds to a linear diameter of about 24 light years; its central density is about 6.21 stars per cubic parsec. Some authors have estimated a larger diameter of up to 46' (H. Shapley in 1930). With about 100 million years (WEBDA gives a value 95, the Sky Catalogue 2000.0 of 110 million years), i ...
... corresponds to a linear diameter of about 24 light years; its central density is about 6.21 stars per cubic parsec. Some authors have estimated a larger diameter of up to 46' (H. Shapley in 1930). With about 100 million years (WEBDA gives a value 95, the Sky Catalogue 2000.0 of 110 million years), i ...
September Globular Clusters - Salisbury Plain Observing Group
... good “non comet”. It is fairly easy to find, lying south west of an open chevron shaped asterism. It is around 55 light years across and is 27,000 light years away. Moderate powers used with a 6” start to resolve the cluster into its individual stars. Leaving Lyra, Delphinus is the next destination, ...
... good “non comet”. It is fairly easy to find, lying south west of an open chevron shaped asterism. It is around 55 light years across and is 27,000 light years away. Moderate powers used with a 6” start to resolve the cluster into its individual stars. Leaving Lyra, Delphinus is the next destination, ...
M = 5.5 - The Millstone
... Their spectra are deficient in metal lines, showing that they are sub-dwarfs (luminosity class VI) formed before the recycling of stellar material in such processes as supernova explosion had properly begun. ...
... Their spectra are deficient in metal lines, showing that they are sub-dwarfs (luminosity class VI) formed before the recycling of stellar material in such processes as supernova explosion had properly begun. ...
Star Clusters and their stars
... clusters orbiting our Galaxy. They typically have 105 – 106 stars. They are spherically distributed around the center of our Galaxy. They tend to concentrate towards the center of the Galaxy, with many in the constellations Sagittarius, Scorpio and Ophiunchus It was by studying the distribution of g ...
... clusters orbiting our Galaxy. They typically have 105 – 106 stars. They are spherically distributed around the center of our Galaxy. They tend to concentrate towards the center of the Galaxy, with many in the constellations Sagittarius, Scorpio and Ophiunchus It was by studying the distribution of g ...
Star_Clusters
... clusters orbiting our Galaxy. They typically have 105 – 106 stars. They are spherically distributed around the center of our Galaxy. They tend to concentrate towards the center of the Galaxy, with many in the constellations Sagittarius, Scorpio and Ophiunchus It was by studying the distribution of g ...
... clusters orbiting our Galaxy. They typically have 105 – 106 stars. They are spherically distributed around the center of our Galaxy. They tend to concentrate towards the center of the Galaxy, with many in the constellations Sagittarius, Scorpio and Ophiunchus It was by studying the distribution of g ...
How Stars Form Powerpoint
... Individual cloud fragments begin to collapse. Once the density is high enough, there is no ...
... Individual cloud fragments begin to collapse. Once the density is high enough, there is no ...
The mass function of star clusters formed in turbulent molecular clouds
... In the MW: The most massive GMC =~107Msun -> The most massive cluster = ~104Msun -> The most massive star = ~150Msun ...
... In the MW: The most massive GMC =~107Msun -> The most massive cluster = ~104Msun -> The most massive star = ~150Msun ...
A Star is “Born,” and then How Will it Move
... will dissolve in ~10’s of Myr to 1 Gyr (typically in 100’s of Myr) Young (Embedded) Clusters: Very young (<10 Myr-old) groups of young stars that form together. Future binding depends on cluster mass & velocity, seems that 90% dissolve before ~10 Myr (Lada & Lada 2003). When they unbind but are stil ...
... will dissolve in ~10’s of Myr to 1 Gyr (typically in 100’s of Myr) Young (Embedded) Clusters: Very young (<10 Myr-old) groups of young stars that form together. Future binding depends on cluster mass & velocity, seems that 90% dissolve before ~10 Myr (Lada & Lada 2003). When they unbind but are stil ...
The Milky Way Galaxy
... Herschel didn’t know about different kinds of stars, he thought they were all the same (like the sun) and therefore all the same luminosity. Using this assumption, he could just simply compute the distance from the brightness. Brightness = Luminosity/(distance)2 ...
... Herschel didn’t know about different kinds of stars, he thought they were all the same (like the sun) and therefore all the same luminosity. Using this assumption, he could just simply compute the distance from the brightness. Brightness = Luminosity/(distance)2 ...
PowerPoint File
... Measure the distance over which the density of stars significantly falls off with height above, or distance below, the galactic plane. The distance depends on the type of objects considered, but is roughly 100 – 200 parsecs. The galactic plane is much thinner than it is wide. ...
... Measure the distance over which the density of stars significantly falls off with height above, or distance below, the galactic plane. The distance depends on the type of objects considered, but is roughly 100 – 200 parsecs. The galactic plane is much thinner than it is wide. ...
THE MILKY WAY GALAXY
... The Milky Way (MW) is the name given to the faint band of light visible in the night sky. This light is the sum of billions of stars comprising our home galaxy. Today, we understand that the Milky Way is a flattened, rotating disk of stars, gas and dust, about 100,000 light years in diameter. The de ...
... The Milky Way (MW) is the name given to the faint band of light visible in the night sky. This light is the sum of billions of stars comprising our home galaxy. Today, we understand that the Milky Way is a flattened, rotating disk of stars, gas and dust, about 100,000 light years in diameter. The de ...
Document
... • We define our age by trips around the Sun. • How many trips of Sun around Milky Way? R = 8.5 kpc V = 220km/s P = 2.5x108 yrs ...
... • We define our age by trips around the Sun. • How many trips of Sun around Milky Way? R = 8.5 kpc V = 220km/s P = 2.5x108 yrs ...
galaxies
... Globular Clusters • millions to hundreds of millions of stars • old! 6 to 13 billion years • mostly red giants and dwarfs • stars are clumped closely together, especially near the center of the cluster (densely) • surround our disk as a halo Image at http://hubblesite.org/newscenter/archive/release ...
... Globular Clusters • millions to hundreds of millions of stars • old! 6 to 13 billion years • mostly red giants and dwarfs • stars are clumped closely together, especially near the center of the cluster (densely) • surround our disk as a halo Image at http://hubblesite.org/newscenter/archive/release ...
Document
... • We define our age by trips around the Sun. • How many trips of Sun around Milky Way? R = 8.5 kpc V = 220km/s P = 2.5x108 yrs ...
... • We define our age by trips around the Sun. • How many trips of Sun around Milky Way? R = 8.5 kpc V = 220km/s P = 2.5x108 yrs ...
Photometric analysis of the globular cluster NGC5466
... (B − V) vs V diagram combining the aperture and the PSF photometry techniques. Then, we analysed the diagram adopting two different procedures: the first consisted in comparing our diagram with the theoretical isochrones, the second was the RR-Lyrae method; both methods gave us an estimation of the ...
... (B − V) vs V diagram combining the aperture and the PSF photometry techniques. Then, we analysed the diagram adopting two different procedures: the first consisted in comparing our diagram with the theoretical isochrones, the second was the RR-Lyrae method; both methods gave us an estimation of the ...
Groups of Stars
... • Many stars exist in groups of two or more stars that are held close together because of gravity • More than half of all stars are members of star systems • Is our Sun part of a star system? ...
... • Many stars exist in groups of two or more stars that are held close together because of gravity • More than half of all stars are members of star systems • Is our Sun part of a star system? ...
Hypervelocity Globular: A beacon of merging clusters Oleg Gnedin with Alexey Vikhlinin
... While measuring radial velocities of globular clusters around M87 in Virgo Cluster, Caldwell et al. (2014) found an outlier… A triple interaction with a binary black hole (slingshot) can lead to a very high ejection velocity. ...
... While measuring radial velocities of globular clusters around M87 in Virgo Cluster, Caldwell et al. (2014) found an outlier… A triple interaction with a binary black hole (slingshot) can lead to a very high ejection velocity. ...
Groups_of_Stars_spectra
... Dopplar/Wavelength Shifts In space there is no up down left or right, only towards or away • Motion towards & away causes the light given off to be squeezed or stretched • Blue-shift: wavelengths from objects moving toward another get squeezed • Red-shift: wavelengths from objects moving away get s ...
... Dopplar/Wavelength Shifts In space there is no up down left or right, only towards or away • Motion towards & away causes the light given off to be squeezed or stretched • Blue-shift: wavelengths from objects moving toward another get squeezed • Red-shift: wavelengths from objects moving away get s ...
Open cluster
An open cluster, also known as galactic cluster, is a group of up to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way Galaxy, and many more are thought to exist. They are loosely bound by mutual gravitational attraction and become disrupted by close encounters with other clusters and clouds of gas as they orbit the galactic center, resulting in a migration to the main body of the galaxy as well as a loss of cluster members through internal close encounters. Open clusters generally survive for a few hundred million years, with the most massive ones surviving for a few billion years. In contrast, the more massive globular clusters of stars exert a stronger gravitational attraction on their members, and can survive for longer. Open clusters have been found only in spiral and irregular galaxies, in which active star formation is occurring.Young open clusters may still be contained within the molecular cloud from which they formed, illuminating it to create an H II region. Over time, radiation pressure from the cluster will disperse the molecular cloud. Typically, about 10% of the mass of a gas cloud will coalesce into stars before radiation pressure drives the rest of the gas away.Open clusters are key objects in the study of stellar evolution. Because the cluster members are of similar age and chemical composition, their properties (such as distance, age, metallicity and extinction) are more easily determined than they are for isolated stars. A number of open clusters, such as the Pleiades, Hyades or the Alpha Persei Cluster are visible with the naked eye. Some others, such as the Double Cluster, are barely perceptible without instruments, while many more can be seen using binoculars or telescopes. The Wild Duck Cluster, M11, is an example.