3. Measuring Distances and Magnitudes
... In 1856, N. R. Pogson verified William Herschel’s finding that a firstmagnitude star is 100 times brighter than a sixth-magnitude star and the scale was quantified. Because an interval of five magnitudes corresponds to a factor of 100 in brightness, a one-magnitude difference corresponds to a factor ...
... In 1856, N. R. Pogson verified William Herschel’s finding that a firstmagnitude star is 100 times brighter than a sixth-magnitude star and the scale was quantified. Because an interval of five magnitudes corresponds to a factor of 100 in brightness, a one-magnitude difference corresponds to a factor ...
The Scales of Things
... The first stellar parallax (of the star 61 Cygni) was measured by Friedrich Wilhelm Bessel (1784-1846) in 1838. Bessel is also known for the Bessel functions in mathematical physics. ...
... The first stellar parallax (of the star 61 Cygni) was measured by Friedrich Wilhelm Bessel (1784-1846) in 1838. Bessel is also known for the Bessel functions in mathematical physics. ...
2. The Universe Is Expanding and Evolving
... stars or planets could ever have formed in our universe. But if there were even tiny irregularities in the distribution of matter in the early universe, the slightly denser regions could accrete matter from less dense regions by simple gravitational attraction (even though the overall universe was e ...
... stars or planets could ever have formed in our universe. But if there were even tiny irregularities in the distribution of matter in the early universe, the slightly denser regions could accrete matter from less dense regions by simple gravitational attraction (even though the overall universe was e ...
The Constellations
... • Stars do move back a nd forth (a teeny-tiny bit) in the sky over the course of the year also, due to the revolution of Earth around the Sun (stellar parallax). Note that this motion is not possible to observe without the help of modern telescopes. • Position of stars is different at different loca ...
... • Stars do move back a nd forth (a teeny-tiny bit) in the sky over the course of the year also, due to the revolution of Earth around the Sun (stellar parallax). Note that this motion is not possible to observe without the help of modern telescopes. • Position of stars is different at different loca ...
Discovery of a strong magnetic field in the rapidly rotating B2Vn star
... We used the multiline analysis method of least-squares deconvolution (LSD; Donati et al. 1997) to produce mean Stokes I and V profiles from our spectra. These profiles are illustrated in Fig. 1. The details of the LSD method as applied to B stars are described by Silvester et al. (2009). The LSD lin ...
... We used the multiline analysis method of least-squares deconvolution (LSD; Donati et al. 1997) to produce mean Stokes I and V profiles from our spectra. These profiles are illustrated in Fig. 1. The details of the LSD method as applied to B stars are described by Silvester et al. (2009). The LSD lin ...
Millisecond Pulsar Binaries at Transition
... accretion to the pulsar occurred during the time Since the relaxation time for the companion is much longer than 10 yrs since the interacting activity of the binary, the mass transfer and disk formation may occur again, providing a good source for studying the disk evolution and its interaction with ...
... accretion to the pulsar occurred during the time Since the relaxation time for the companion is much longer than 10 yrs since the interacting activity of the binary, the mass transfer and disk formation may occur again, providing a good source for studying the disk evolution and its interaction with ...
Discovery of a strong magnetic field in the rapidly rotating B2 Vn star
... We used the multiline analysis method of least-squares deconvolution (LSD; Donati et al. 1997) to produce mean Stokes I and V profiles from our spectra. These profiles are illustrated in Fig. 1. The details of the LSD method as applied to B stars are described by Silvester et al. (2009). The LSD lin ...
... We used the multiline analysis method of least-squares deconvolution (LSD; Donati et al. 1997) to produce mean Stokes I and V profiles from our spectra. These profiles are illustrated in Fig. 1. The details of the LSD method as applied to B stars are described by Silvester et al. (2009). The LSD lin ...
Gresham Lecture, Wednesday 15 December 2010 Unsolved
... apparent "asymmetry", or difference, between matter and antimatter to explain why there arose this tiny excess of matter over antimatter. Today, antimatter is created primarily by cosmic rays - extraterrestrial high-energy particles that form new particles as they penetrate the earth's atmosphere. I ...
... apparent "asymmetry", or difference, between matter and antimatter to explain why there arose this tiny excess of matter over antimatter. Today, antimatter is created primarily by cosmic rays - extraterrestrial high-energy particles that form new particles as they penetrate the earth's atmosphere. I ...
The Be/X-ray transient V0332153: evidence for a tilt between the
... accretion disc, was detected (Takeshima et al. 1994). V0332153 has not been detected by the BATSE experiment since the CGRO satellite started operations in 1991 April (Bildsten et al. 1997). It is not detected with any significance by the All-Sky Monitor (ASM) on board RXTE either, according to the ...
... accretion disc, was detected (Takeshima et al. 1994). V0332153 has not been detected by the BATSE experiment since the CGRO satellite started operations in 1991 April (Bildsten et al. 1997). It is not detected with any significance by the All-Sky Monitor (ASM) on board RXTE either, according to the ...
common constellations
... slaves specific routes they could navigate using Polaris. By the beginning of the Civil War in 1861, about 500 people a year were traveling in the South teaching routes to slaves, and well established escape routes had been established. Scholars estimate that 60,000 to 100,000 slaves successfully fl ...
... slaves specific routes they could navigate using Polaris. By the beginning of the Civil War in 1861, about 500 people a year were traveling in the South teaching routes to slaves, and well established escape routes had been established. Scholars estimate that 60,000 to 100,000 slaves successfully fl ...
How many galaxies are there in the Universe?
... 5. So how many stars are in the Universe ? Our Milky Way galaxy contains about 100 billion stars. It is slightly larger than average, so let us assume the average galaxy contains only 50 billion stars. Remember: 1 billion = 109 = 1,000,000,000 = 1 thousand million Estimate for total no. of stars in ...
... 5. So how many stars are in the Universe ? Our Milky Way galaxy contains about 100 billion stars. It is slightly larger than average, so let us assume the average galaxy contains only 50 billion stars. Remember: 1 billion = 109 = 1,000,000,000 = 1 thousand million Estimate for total no. of stars in ...
101 Science Misconceptions
... #29 - The electron cloud is like a rain cloud with the electrons suspended inside like water droplets. Like the shell, the electron cloud is a misnomer. There is no cloud of matter of any kind. It is merely a region in which electrons are constantly moving. Since they are in constant motion, they ob ...
... #29 - The electron cloud is like a rain cloud with the electrons suspended inside like water droplets. Like the shell, the electron cloud is a misnomer. There is no cloud of matter of any kind. It is merely a region in which electrons are constantly moving. Since they are in constant motion, they ob ...
10 Astrophysics (Option E)
... gets light, and when it goes down, it gets dark. If people counted the sun-ups and sundowns, they could predict when flowers would bloom and fruit ripen, and from the position of the Moon they could calculate the tides. Since the largest objects in the sky gave such good predictions, it was a small ...
... gets light, and when it goes down, it gets dark. If people counted the sun-ups and sundowns, they could predict when flowers would bloom and fruit ripen, and from the position of the Moon they could calculate the tides. Since the largest objects in the sky gave such good predictions, it was a small ...
Abundances of RGB stars in NGC 6752 Grundahl
... The primordial scenario, and variations on it, has been proposed and discussed several times before in the literature (see for example Cottrell & Da Costa 1981, and Cannon et al. 1998). The small star–to–star scatter in the iron peak elements (as observed in this work) indicates that the contributio ...
... The primordial scenario, and variations on it, has been proposed and discussed several times before in the literature (see for example Cottrell & Da Costa 1981, and Cannon et al. 1998). The small star–to–star scatter in the iron peak elements (as observed in this work) indicates that the contributio ...
2009 - thephysicsteacher.ie
... Why do stars and the lights of distant objects twinkle? The twinkling of stars, also known as stellar scintillation, is due to atmospheric turbulence. The turbulence of the air is caused by heat changing the density and thus the refractive index of moving pockets of air in the earth's atmosphere. Th ...
... Why do stars and the lights of distant objects twinkle? The twinkling of stars, also known as stellar scintillation, is due to atmospheric turbulence. The turbulence of the air is caused by heat changing the density and thus the refractive index of moving pockets of air in the earth's atmosphere. Th ...
Star formation
Star formation is the process by which dense regions within molecular clouds in interstellar space, sometimes referred to as ""stellar nurseries"" or ""star-forming regions"", collapse to form stars. As a branch of astronomy, star formation includes the study of the interstellar medium (ISM) and giant molecular clouds (GMC) as precursors to the star formation process, and the study of protostars and young stellar objects as its immediate products. It is closely related to planet formation, another branch of astronomy. Star formation theory, as well as accounting for the formation of a single star, must also account for the statistics of binary stars and the initial mass function.In June 2015, astronomers reported evidence for Population III stars in the Cosmos Redshift 7 galaxy at z = 6.60. Such stars are likely to have existed in the very early universe (i.e., at high redshift), and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life as we know it.