Elliptical Galaxies
... where Re , the effective radius, is the radius that contains half the total light of the galaxy and Ie is the surface brightness (the amount of light from a square arc second of the galaxy) at Re . This law can be integrated to give a finite total light of Itot = 7.22πRe 2 Ie . de Vaucouleurs’ law, ...
... where Re , the effective radius, is the radius that contains half the total light of the galaxy and Ie is the surface brightness (the amount of light from a square arc second of the galaxy) at Re . This law can be integrated to give a finite total light of Itot = 7.22πRe 2 Ie . de Vaucouleurs’ law, ...
The most metal-poor galaxies
... have heavy element abundances 10−4 times that of the Sun (Cayrel 1996) while stars in the Galactic centre may be three times more metal rich than the Sun. On the other hand, the large ionised complexes in the ISM show a narrower range down to only 1/10 the solar value. Thus metallicity depends on wh ...
... have heavy element abundances 10−4 times that of the Sun (Cayrel 1996) while stars in the Galactic centre may be three times more metal rich than the Sun. On the other hand, the large ionised complexes in the ISM show a narrower range down to only 1/10 the solar value. Thus metallicity depends on wh ...
Giant star seismology
... Asteroseismology – the study of global properties of stars and their internal structure through their global intrinsic oscillations – is already more than a century old. An early remarkable result was obtained for Cepheids revealing the period-luminosity relation (Leavitt and Pickering, 1912), which ...
... Asteroseismology – the study of global properties of stars and their internal structure through their global intrinsic oscillations – is already more than a century old. An early remarkable result was obtained for Cepheids revealing the period-luminosity relation (Leavitt and Pickering, 1912), which ...
IOTA Observer`s Manual
... Occultation observations have been used for hundreds of years by sailors to determine time and their position at sea. Modern occultation observations are routinely used to refine the orbit of the Moon, analyze the positions of stars and the coordinate system they represent, detect new stellar compan ...
... Occultation observations have been used for hundreds of years by sailors to determine time and their position at sea. Modern occultation observations are routinely used to refine the orbit of the Moon, analyze the positions of stars and the coordinate system they represent, detect new stellar compan ...
Tuomas Kangas
... evolution and spectral features of a SN. Mass loss before the SN results in a circumstellar medium (CSM), signatures of which can in some cases clearly be seen in the SN. The mutual interaction between stars in a multiple stellar system also has a profound effect on the evolution of the system, and ...
... evolution and spectral features of a SN. Mass loss before the SN results in a circumstellar medium (CSM), signatures of which can in some cases clearly be seen in the SN. The mutual interaction between stars in a multiple stellar system also has a profound effect on the evolution of the system, and ...
The evolution of low-metallicity massive stars - Argelander
... Stars are isolated gas-spheres in outer space, bound together by gravity, radiating away light released by nuclear fusion. But their story is not that simple, as anyone who looks through a telescope would soon figure out. Because there are stars in the dark spots of the sky, too faint for the naked ...
... Stars are isolated gas-spheres in outer space, bound together by gravity, radiating away light released by nuclear fusion. But their story is not that simple, as anyone who looks through a telescope would soon figure out. Because there are stars in the dark spots of the sky, too faint for the naked ...
Comet Kirch in Art and Astronomy
... reached its perihelion on 8th of December 1680 (18th December) passing at a distance of 0,0062 AU (around 930000 km) from the Sun, and its closest approach to the Earth was on 20th of November (30th November N. S.) of 0,42 AU. The Kirch Comet was visible with naked eye before sunrise and after sunse ...
... reached its perihelion on 8th of December 1680 (18th December) passing at a distance of 0,0062 AU (around 930000 km) from the Sun, and its closest approach to the Earth was on 20th of November (30th November N. S.) of 0,42 AU. The Kirch Comet was visible with naked eye before sunrise and after sunse ...
Mirrors vs. Dielectric vs. Prism Diagonal Comparison
... aberration on bright stars, and scatter around bright stars. The Takahashi TSA-102 f/8 Super APO was used for all tests. However, since it is popularly reported that a prism diagonal can induce chromatic aberration (CA) with faster focal ratios, for CA tests a Celestron f/6.25 80mm Onyx APO was also ...
... aberration on bright stars, and scatter around bright stars. The Takahashi TSA-102 f/8 Super APO was used for all tests. However, since it is popularly reported that a prism diagonal can induce chromatic aberration (CA) with faster focal ratios, for CA tests a Celestron f/6.25 80mm Onyx APO was also ...
Galaxies - Valhalla High School
... gas, and dust content and some are more “active” than others Galaxies tend to cluster together and these clusters appear to be separating from each other, caught up in a Universe that is expanding The why for all this diversity is as yet unanswered ...
... gas, and dust content and some are more “active” than others Galaxies tend to cluster together and these clusters appear to be separating from each other, caught up in a Universe that is expanding The why for all this diversity is as yet unanswered ...
Mapping the Pathways of Galaxy Transformation Across Time and
... activity, stellar mass assembly, and morphology. In this talk, I will illustrate the relation between global properties and kpc-scale substructures of galaxies out to z∼2. Using combined high resolution data from the Hubble Space Telescope and long exposure spectroscopic observations with the Keck t ...
... activity, stellar mass assembly, and morphology. In this talk, I will illustrate the relation between global properties and kpc-scale substructures of galaxies out to z∼2. Using combined high resolution data from the Hubble Space Telescope and long exposure spectroscopic observations with the Keck t ...
abū`l faẓl, independent discoverer of the great comet of 1577
... Abū‘l Faẓl (1551–1602), who came to the court of the Mughal Emperor Jalāl ud-Din Muḥammad Akbar (1542–1605; ruled 1556–1605) in CE 1575, was a very knowledgeable person, having trained in the traditional as well as the rational (natural) sciences. He wrote in Persian the official biographical accoun ...
... Abū‘l Faẓl (1551–1602), who came to the court of the Mughal Emperor Jalāl ud-Din Muḥammad Akbar (1542–1605; ruled 1556–1605) in CE 1575, was a very knowledgeable person, having trained in the traditional as well as the rational (natural) sciences. He wrote in Persian the official biographical accoun ...
Famous Comets - Mr. Hill`s Science Website
... and see the Moon and lots of stars. Sometimes though, the Moon and stars are joined by other objects. If you looked into the sky on an evening early in 1997, you may have been able to see what looked like a star which had been smudged. In fact, this smudged star was a comet, one of the brightest com ...
... and see the Moon and lots of stars. Sometimes though, the Moon and stars are joined by other objects. If you looked into the sky on an evening early in 1997, you may have been able to see what looked like a star which had been smudged. In fact, this smudged star was a comet, one of the brightest com ...
The visibility of Lyman Alpha Emitters: constraining reionization
... number of physical effects. First, the intrinsic Lyα luminosity depends on the total number of H I ionizing photons that are produced by a galaxy, depending on the star formation rate (SFR), age and metallicity of its stellar population (e.g. Santos 2004). Second, depending on the H I and dust conte ...
... number of physical effects. First, the intrinsic Lyα luminosity depends on the total number of H I ionizing photons that are produced by a galaxy, depending on the star formation rate (SFR), age and metallicity of its stellar population (e.g. Santos 2004). Second, depending on the H I and dust conte ...
Here - NASA/IPAC Extragalactic Database
... at which one is working). The effective temperatures T? of the ionizing stars lie in the range 35 000 – 50 000 K. The nebular geometries result from the structure of the parent molecular cloud. Stellar winds, at evolved stages, may produce ring-like structures, but the morphology of H ii regions is ...
... at which one is working). The effective temperatures T? of the ionizing stars lie in the range 35 000 – 50 000 K. The nebular geometries result from the structure of the parent molecular cloud. Stellar winds, at evolved stages, may produce ring-like structures, but the morphology of H ii regions is ...
Set 2 Astronomy questions
... Members of the “Key Project”, while working with the Hubble space telescope, are using observation primarily of what specific type of celestial object to calculate the Hubble constant? ANSWER: CEPHEIDS (ACCEPT: CEPHEID VARIABLES) BONUS 12) ASTRONOMY Short Answer Rounded to the first decimal place, h ...
... Members of the “Key Project”, while working with the Hubble space telescope, are using observation primarily of what specific type of celestial object to calculate the Hubble constant? ANSWER: CEPHEIDS (ACCEPT: CEPHEID VARIABLES) BONUS 12) ASTRONOMY Short Answer Rounded to the first decimal place, h ...
Woofer-Tweeter Adaptive Optics for Astronomy
... The Earth’s atmosphere has long been identified as a limiting factor in astronomical observations. The ‘tremors of the atmosphere’ that Newton mentions have the effect of reducing imaging resolution in telescopes far short of diffraction limited performance. When imaging through strong turbulence th ...
... The Earth’s atmosphere has long been identified as a limiting factor in astronomical observations. The ‘tremors of the atmosphere’ that Newton mentions have the effect of reducing imaging resolution in telescopes far short of diffraction limited performance. When imaging through strong turbulence th ...
THE COMET`S TALE - Institute of Astronomy
... hydrogen atoms are aligned or not. The ortho-to-para ratio strongly depends on the physical environment, and would have been preserved when the molecules were confined into the icy cometary nuclei. The observed ratio can therefore reveal the temperature at the time the ice was formed. Molecules in t ...
... hydrogen atoms are aligned or not. The ortho-to-para ratio strongly depends on the physical environment, and would have been preserved when the molecules were confined into the icy cometary nuclei. The observed ratio can therefore reveal the temperature at the time the ice was formed. Molecules in t ...
Sample assessment material | PDF 2.6 MB - Edexcel
... Examiners should also be prepared to award zero marks if the candidate’s response is not worthy of credit according to the mark scheme. ...
... Examiners should also be prepared to award zero marks if the candidate’s response is not worthy of credit according to the mark scheme. ...
Mercury Flyby 3 - Messenger - The Johns Hopkins University
... • Prior to January of this year, Mercury had been visited by only one spacecraft; NASA’s Mariner 10 examined less than half the surface (~45%) in detail during its three flybys in 1974 and 1975. ...
... • Prior to January of this year, Mercury had been visited by only one spacecraft; NASA’s Mariner 10 examined less than half the surface (~45%) in detail during its three flybys in 1974 and 1975. ...
Strongly suggested reading: The stellar halo of the Galaxy
... was discovered. This in itself may be a justification for writing a review, but it also may lead to an article that is rapidly out of date. On the other hand, this of course, is only a sign of the field’s health and its great promise for the young generations of scientists hoping to unravel the form ...
... was discovered. This in itself may be a justification for writing a review, but it also may lead to an article that is rapidly out of date. On the other hand, this of course, is only a sign of the field’s health and its great promise for the young generations of scientists hoping to unravel the form ...
Multiplicity in Early Stellar Evolution - Astronomy Group
... with an initial mass of 500 M⊙, a Jeans mass of 1 M⊙, and a turbulent, high-Mach-number (13.7) velocity field. This simulation involved a sufficiently large population of stars and brown dwarfs (1250) so as to provide an excellent basis for comparison with observed multiple systems. It is remarkable ...
... with an initial mass of 500 M⊙, a Jeans mass of 1 M⊙, and a turbulent, high-Mach-number (13.7) velocity field. This simulation involved a sufficiently large population of stars and brown dwarfs (1250) so as to provide an excellent basis for comparison with observed multiple systems. It is remarkable ...
Was the bright comet of 1742 discovered from India?
... his description has turned out to be correct selectively as somewhere it runs counter to the brightness estimates. On the face of it, the Shawwāl observation is perplexing. However, I can explain it in one possible way. Comets can be unreliable in respect of their activity (read brightness) in their ...
... his description has turned out to be correct selectively as somewhere it runs counter to the brightness estimates. On the face of it, the Shawwāl observation is perplexing. However, I can explain it in one possible way. Comets can be unreliable in respect of their activity (read brightness) in their ...
X-Ray Spectroscopy of Stars
... giants of spectral type M. But even for those two classes, important exceptions exist. X-rays have been identified from the most massive and hottest stars, i.e., O-type and Wolf-Rayet stars, for which shocks forming in unstable winds are held responsible for the production of million-degree plasma a ...
... giants of spectral type M. But even for those two classes, important exceptions exist. X-rays have been identified from the most massive and hottest stars, i.e., O-type and Wolf-Rayet stars, for which shocks forming in unstable winds are held responsible for the production of million-degree plasma a ...
International Ultraviolet Explorer
The International Ultraviolet Explorer (IUE) was an astronomical observatory satellite primarily designed to take ultraviolet spectra. The satellite was a collaborative project between NASA, the UK Science Research Council and the European Space Agency (ESA). The mission was first proposed in early 1964, by a group of scientists in the United Kingdom, and was launched on January 26, 1978 aboard a NASA Delta rocket. The mission lifetime was initially set for 3 years, but in the end it lasted almost 18 years, with the satellite being shut down in 1996. The switch-off occurred for financial reasons, while the telescope was still functioning at near original efficiency.It was the first space observatory to be operated in real time by astronomers who visited the groundstations in the United States and Europe. Astronomers made over 104,000 observations using the IUE, of objects ranging from solar system bodies to distant quasars. Among the significant scientific results from IUE data were the first large scale studies of stellar winds, accurate measurements of the way interstellar dust absorbs light, and measurements of the supernova SN1987A which showed that it defied stellar evolution theories as they then stood. When the mission ended, it was considered the most successful astronomical satellite ever.