The HERMES GALAH survey: overview
... In addition to their defining thin disks, almost all spirals appear to have a thick disk component. For large spirals like the Milky Way, the thick disk mass is typically about 10% of the thin disk, and its vertical scale height is about 1000 pc; the scale height of the thin disk is typically about ...
... In addition to their defining thin disks, almost all spirals appear to have a thick disk component. For large spirals like the Milky Way, the thick disk mass is typically about 10% of the thin disk, and its vertical scale height is about 1000 pc; the scale height of the thin disk is typically about ...
lect3 — 1 Measuring stars: What can be measured?
... stars tend to be somewhat variable, and their color doesn’t translate into luminosity quite so tightly as for something like the Sun. Cepheids: Classically, this is the most reliable stellar standard candle. This type of giant star is seen to have regular pulsations, and the pulsation period turns o ...
... stars tend to be somewhat variable, and their color doesn’t translate into luminosity quite so tightly as for something like the Sun. Cepheids: Classically, this is the most reliable stellar standard candle. This type of giant star is seen to have regular pulsations, and the pulsation period turns o ...
Massive Star Formation in the Galactic Center
... The three clusters are similar in many respects, as they are all young and contain 104 M in stars. They have very high central stellar mass densities, up to nearly 106 M pc−3 , exceeding central densities in most globular clusters. They have luminosities of 107−8 L , and are responsible for heat ...
... The three clusters are similar in many respects, as they are all young and contain 104 M in stars. They have very high central stellar mass densities, up to nearly 106 M pc−3 , exceeding central densities in most globular clusters. They have luminosities of 107−8 L , and are responsible for heat ...
The Primordial Abundance of $^ 6$ Li and $^ 9$ be
... bluest point of the turnoff (SLN93). However, the effective temperature of this star is too low for it to be a massive main sequence star. Stellar models with the metallicity of HD 84937 typically have turn-off temperatures ranging from 6700 K (age 14 Gyr) to 6540 K (age 18 Gyr). SLN93 suggest that ...
... bluest point of the turnoff (SLN93). However, the effective temperature of this star is too low for it to be a massive main sequence star. Stellar models with the metallicity of HD 84937 typically have turn-off temperatures ranging from 6700 K (age 14 Gyr) to 6540 K (age 18 Gyr). SLN93 suggest that ...
Homework No. 2 Solutions
... section of the Vega spectrum in black. You may assume that Vega is not moving. The red plot is part of the spectrum from another star very similar to Vega except for its Doppler shift. The numbers show the location of the spectral line. You will find It helpful to ...
... section of the Vega spectrum in black. You may assume that Vega is not moving. The red plot is part of the spectrum from another star very similar to Vega except for its Doppler shift. The numbers show the location of the spectral line. You will find It helpful to ...
Astronomy 102, Spring 2003 Solutions to Review Problems
... The stretching of the range that a log plot gives you allows you to see what’s going on with the data. Consider, for example, the HR diagram (e.g Figure 12.15a in the book). If we want to plot all of the stars in this figure, we’d need to make sure the range goes all the way up to at least 10 3 L . ...
... The stretching of the range that a log plot gives you allows you to see what’s going on with the data. Consider, for example, the HR diagram (e.g Figure 12.15a in the book). If we want to plot all of the stars in this figure, we’d need to make sure the range goes all the way up to at least 10 3 L . ...
Data-mining in astrophysics. A search for new variable stars in
... Hoffman et al. (2008) used Fourier analysis method to determine the period of the candidates. A Fourier transform is made for each candidate’s light curve and the power spectrum is analyzed. The periods implied by the top two power peaks and their closest two harmonics (half and twice the frequency) ...
... Hoffman et al. (2008) used Fourier analysis method to determine the period of the candidates. A Fourier transform is made for each candidate’s light curve and the power spectrum is analyzed. The periods implied by the top two power peaks and their closest two harmonics (half and twice the frequency) ...
CENTRAL TEXAS COLLEGE
... given in those cases where the student has completed the majority of the course work, but because of personal illness, death in the immediate family, or military orders, the student is unable to complete the requirements for a course...” Prior approval from the instructor is required before the grad ...
... given in those cases where the student has completed the majority of the course work, but because of personal illness, death in the immediate family, or military orders, the student is unable to complete the requirements for a course...” Prior approval from the instructor is required before the grad ...
Brown dwarfs: Failed stars, super Jupiters
... characterize the entire population. To the human eye, however, most brown dwarfs would appear magenta. Early searches for brown dwarfs were driven in part by speculation that they could be a major component of dark matter. (They are not.) However, it was not until the mid1990s that the first brown d ...
... characterize the entire population. To the human eye, however, most brown dwarfs would appear magenta. Early searches for brown dwarfs were driven in part by speculation that they could be a major component of dark matter. (They are not.) However, it was not until the mid1990s that the first brown d ...
The Carina Dwarf Spheroidal Galaxy: A Goldmine for Cosmology
... satellite populations significantly larger than the number of dwarfs observed near giant spirals like the Milky Way and M31. This discrepancy is known as the missing satellite problem and challenges the current most popular cosmological model: the Lambda Cold Dark Matter paradigm (Madau et al., 200 ...
... satellite populations significantly larger than the number of dwarfs observed near giant spirals like the Milky Way and M31. This discrepancy is known as the missing satellite problem and challenges the current most popular cosmological model: the Lambda Cold Dark Matter paradigm (Madau et al., 200 ...
Astronomical and Physical Sciences
... changes could occur in almost perfect step with the slow increase in the Sun’s radiation. • Until some evidence supports such “special pleadings,” it does not appear the Sun evolved. • If the Sun, a typical and well-studied star, did not evolve, then why presume that all other stars did? ...
... changes could occur in almost perfect step with the slow increase in the Sun’s radiation. • Until some evidence supports such “special pleadings,” it does not appear the Sun evolved. • If the Sun, a typical and well-studied star, did not evolve, then why presume that all other stars did? ...
Contrast the old definition of constellation with the
... If all stars are circumpolar if you lived at the north pole, and all stars rise and set if you lived on the equator, what can you state about the motion of stars if you lived in between the north pole and the equator? ...
... If all stars are circumpolar if you lived at the north pole, and all stars rise and set if you lived on the equator, what can you state about the motion of stars if you lived in between the north pole and the equator? ...
Lecture 16, AGN Evolution
... common to use terms interchangeably – About 10x more numerous than radio-loud quasars ...
... common to use terms interchangeably – About 10x more numerous than radio-loud quasars ...
S T A R S
... star clusters, nebulae and galaxies.) Omega Centauri was named as a fourth magnitude star almost 2000 years ago. In 1677 Halley observed it as a cluster and not as a star. Now there are known to be over a million stars in the cluster with some 1000 times more bright than our sun. The cluster is abou ...
... star clusters, nebulae and galaxies.) Omega Centauri was named as a fourth magnitude star almost 2000 years ago. In 1677 Halley observed it as a cluster and not as a star. Now there are known to be over a million stars in the cluster with some 1000 times more bright than our sun. The cluster is abou ...
55-80 BIOGRAPHY_of_A STAR
... Our Sun’s Story …and that of heavy stars mass of a star determines its core pressure and temperature: our sun’s low mass cooler core and slower fusion rate lower internal temperature, and external (yellow) ...
... Our Sun’s Story …and that of heavy stars mass of a star determines its core pressure and temperature: our sun’s low mass cooler core and slower fusion rate lower internal temperature, and external (yellow) ...
The Sun and Stars
... Reading H-R H-R diagrams are useful because they help astronomers categorize diagrams stars into groups. Stars that fall in the band that stretches diagonally from cool, dim stars to hot, bright stars are called main sequence stars. Main sequence stars, like the sun, are in a very stable part of the ...
... Reading H-R H-R diagrams are useful because they help astronomers categorize diagrams stars into groups. Stars that fall in the band that stretches diagonally from cool, dim stars to hot, bright stars are called main sequence stars. Main sequence stars, like the sun, are in a very stable part of the ...
1/2016
... Description: Delta Cephei is the prototype of the Cepheid class of variable stars. With a change in visual magnitude of 3.5 to 4.4, delta Cephei’s entire range of variability can be observed with the unaided eye. Its period of 5.366 days makes it an attractive candidate for anyone anxious to obtain ...
... Description: Delta Cephei is the prototype of the Cepheid class of variable stars. With a change in visual magnitude of 3.5 to 4.4, delta Cephei’s entire range of variability can be observed with the unaided eye. Its period of 5.366 days makes it an attractive candidate for anyone anxious to obtain ...
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.