Age Estimates of Globular Clusters in the Milky Way
... are thought to have coalesced early on from small-scale density fluctuations in the primordial gas cloud, which itself later coherently collapsed, dissipating its energy and settling into the disk of our Milky Way Galaxy. As a result, these objects populate a roughly spherical halo in our galaxy toda ...
... are thought to have coalesced early on from small-scale density fluctuations in the primordial gas cloud, which itself later coherently collapsed, dissipating its energy and settling into the disk of our Milky Way Galaxy. As a result, these objects populate a roughly spherical halo in our galaxy toda ...
HR 6060: The Closest Ever Solar Twin
... same degree of activity. Our estimated projected rotation velocity for HR 6060 is vseni \leq 3,0 Km/s, from a selected set of Fe I lines with very clean profiles. The abundances in HR 6060 of log N(Li) < 1.4 (Soderblom 1983) and log N(Be) = 1.15 ± 0.15 (Boesgaard & King 1993) are solar: log N(Li)sun ...
... same degree of activity. Our estimated projected rotation velocity for HR 6060 is vseni \leq 3,0 Km/s, from a selected set of Fe I lines with very clean profiles. The abundances in HR 6060 of log N(Li) < 1.4 (Soderblom 1983) and log N(Be) = 1.15 ± 0.15 (Boesgaard & King 1993) are solar: log N(Li)sun ...
IYA 2009 - AAVSO Beginner/Intermediate Amateur Astronomer
... When there is discussion of spectroscopy of stars you will here hydrogen alpha line mentioned a lot. Since stars are mainly hydrogen and since the hydrogen alpha line is the most prominent line for the element, it gets lots of study. For epsilon Aurigae other hydrogen lines are also of . interest in ...
... When there is discussion of spectroscopy of stars you will here hydrogen alpha line mentioned a lot. Since stars are mainly hydrogen and since the hydrogen alpha line is the most prominent line for the element, it gets lots of study. For epsilon Aurigae other hydrogen lines are also of . interest in ...
Why Spectroscopy?
... When there is discussion of spectroscopy of stars you will here hydrogen alpha line mentioned a lot. Since stars are mainly hydrogen and since the hydrogen alpha line is the most prominent line for the element, it gets lots of study. For epsilon Aurigae other hydrogen lines are also of . interest in ...
... When there is discussion of spectroscopy of stars you will here hydrogen alpha line mentioned a lot. Since stars are mainly hydrogen and since the hydrogen alpha line is the most prominent line for the element, it gets lots of study. For epsilon Aurigae other hydrogen lines are also of . interest in ...
Habitability of super-Earth planets around main
... It is the purpose of this paper to expand the focus of Paper I, which is solely focused on the Sun. Paper I is based on the concept that the habitability of super-Earth planets is evaluated via a modified Earth system model that describes the evolution of the temperature and atmospheric CO2 concentra ...
... It is the purpose of this paper to expand the focus of Paper I, which is solely focused on the Sun. Paper I is based on the concept that the habitability of super-Earth planets is evaluated via a modified Earth system model that describes the evolution of the temperature and atmospheric CO2 concentra ...
6.1 Introduction
... in the gas from which stars have recently formed, such as the Orion nebula. Possibly these most metal-poor stars have been enriched by only one previous generation of stars which themselves presumably formed out of pristine gas. Thus, the chemical composition of the most metal-poor stars known is on ...
... in the gas from which stars have recently formed, such as the Orion nebula. Possibly these most metal-poor stars have been enriched by only one previous generation of stars which themselves presumably formed out of pristine gas. Thus, the chemical composition of the most metal-poor stars known is on ...
Betelgeuse: an unauthorized biography
... (i.e. main sequence) mass 15+2 –5 M, the 15 M corresponding (with mass loss rates from Schaller et al.) to about 13.7 M now. This mass, combined with a radius of 780, 700 or 640 R implies a surface gravity of log g = –0.20, –0.11 and –0.04 respectively, very much in line with the value 0.0 (with ...
... (i.e. main sequence) mass 15+2 –5 M, the 15 M corresponding (with mass loss rates from Schaller et al.) to about 13.7 M now. This mass, combined with a radius of 780, 700 or 640 R implies a surface gravity of log g = –0.20, –0.11 and –0.04 respectively, very much in line with the value 0.0 (with ...
Rotation Periods and Relative Ages of Solar-Type Stars
... context of previously-published hypotheses, calculated rotation periods, or Pcalc, were obtained for each star. These Pcalc are a function of chromospheric activity level as well as B - V spectral type. The formula for the calculation of rotation periods was derived from Noyes’ algorithm for determi ...
... context of previously-published hypotheses, calculated rotation periods, or Pcalc, were obtained for each star. These Pcalc are a function of chromospheric activity level as well as B - V spectral type. The formula for the calculation of rotation periods was derived from Noyes’ algorithm for determi ...
hwd_ewd_v3 - X-ray and Observational Astronomy Group
... following, when the white dwarf first emerges from these as a hot, but more or less dead object. Quite when all nuclear burning ceases is still the subject of some debate, but it is certainly extinguished early in the lifetime of a white dwarf, unless the star is able to accrete material from a comp ...
... following, when the white dwarf first emerges from these as a hot, but more or less dead object. Quite when all nuclear burning ceases is still the subject of some debate, but it is certainly extinguished early in the lifetime of a white dwarf, unless the star is able to accrete material from a comp ...
The Physics of Star Formation: Understanding the Youngest Protostars
... warmer driving central protostars or inner circumstellar regions. Mass accretion rates and luminosities are highly dependent on local volume densities through the sound speed of the gas. As a protostar evolves, the density and temperature pro les of its inner envelope may change (e.g., see Andre et ...
... warmer driving central protostars or inner circumstellar regions. Mass accretion rates and luminosities are highly dependent on local volume densities through the sound speed of the gas. As a protostar evolves, the density and temperature pro les of its inner envelope may change (e.g., see Andre et ...
Girardi
... a continuous rate from 6 to 10 Gyr ago. What is the age distribution of red clump stars? Constant between 6 and 10 Gyr? NO. 6 Gyr old RC stars are ∼ 1.4 times more frequent than the 10-Gyr old, mainly because they leave the MS at a faster rate, and despite the IMF favouring old stars. Similar conclu ...
... a continuous rate from 6 to 10 Gyr ago. What is the age distribution of red clump stars? Constant between 6 and 10 Gyr? NO. 6 Gyr old RC stars are ∼ 1.4 times more frequent than the 10-Gyr old, mainly because they leave the MS at a faster rate, and despite the IMF favouring old stars. Similar conclu ...
VY Canis Majoris: The Astrophysical Basis of Its Luminosity
... implies that at least 2 mag of more of circumstellar extinction is required in the visual to equal the flux emitted at 10µm. The wavelength dependence of the CS extinction correction, however, is not known. ...
... implies that at least 2 mag of more of circumstellar extinction is required in the visual to equal the flux emitted at 10µm. The wavelength dependence of the CS extinction correction, however, is not known. ...
A Star*s Color, Temperature, and Brightness are Related!
... • Today, we honor both scientists by naming the equation after them…the StefanBoltzmann Law: • At the surface of the star, the energy that’s given off per square meter (Watts / m2) called the luminous flux is... W / m2 = 5.67 x 10-8 T4 = σT4 ...
... • Today, we honor both scientists by naming the equation after them…the StefanBoltzmann Law: • At the surface of the star, the energy that’s given off per square meter (Watts / m2) called the luminous flux is... W / m2 = 5.67 x 10-8 T4 = σT4 ...
in search of antimatter in the universe
... Furthermore, if the knots in the Centaurus A jet (Figure 6) are due to jet-gas collisions, then these may provide a bright source of Ps-alpha emission, particularly as they are estimated to have a radius of 0.5-2.5 pc.8 On calculating the number of stars in the Centaurus A jet, the number of planeta ...
... Furthermore, if the knots in the Centaurus A jet (Figure 6) are due to jet-gas collisions, then these may provide a bright source of Ps-alpha emission, particularly as they are estimated to have a radius of 0.5-2.5 pc.8 On calculating the number of stars in the Centaurus A jet, the number of planeta ...
X-ray Binaries in Nearby Galaxies
... long-standing problem with distance estimates: very hard to study the X-ray luminosity function and spatial distribution other properties, e.g., orbital period, donor masses known only for a few systems ...
... long-standing problem with distance estimates: very hard to study the X-ray luminosity function and spatial distribution other properties, e.g., orbital period, donor masses known only for a few systems ...
1 solar and stellar abundances of the elements
... that their allotted life span is only a few million years. When we observe a cluster containing brilliant blue stars we can be reasonably sure that we are dealing with a fairly young population. Many such dusters are known, e.g. the Pleiades and the double cluster in Perseus. In a few clusters we ap ...
... that their allotted life span is only a few million years. When we observe a cluster containing brilliant blue stars we can be reasonably sure that we are dealing with a fairly young population. Many such dusters are known, e.g. the Pleiades and the double cluster in Perseus. In a few clusters we ap ...
Riccioli Measures the Stars: Observations of the
... the fixed stars must be 1520 millions of times as great as the earth, or nine millions of times as great as they supposed the sun to be. Now, one of the strong arguments against Ptolemy (and the one which has generally found its way into modern works) was the enormous motion which he supposed the s ...
... the fixed stars must be 1520 millions of times as great as the earth, or nine millions of times as great as they supposed the sun to be. Now, one of the strong arguments against Ptolemy (and the one which has generally found its way into modern works) was the enormous motion which he supposed the s ...
The Mt John University Observatory search for Earth
... with a large enough number of measurements, even signals with amplitudes orders of magnitude below the individual measurement uncertainties can be detected with high significance. Instead of waiting for the new instruments to be deployed, several groups have started ambitious RV programmes that obser ...
... with a large enough number of measurements, even signals with amplitudes orders of magnitude below the individual measurement uncertainties can be detected with high significance. Instead of waiting for the new instruments to be deployed, several groups have started ambitious RV programmes that obser ...
EASTERN ARIZONA COLLEGE Lab - Introduction to Astronomy
... Locate constellations and stars in the sky with a star chart and observe their positions in the sky during a season ...
... Locate constellations and stars in the sky with a star chart and observe their positions in the sky during a season ...
http://www.highpoint.edu/~afuller/PHY-1050
... ejects the H and He into space as a planetary nebula. • The core left behind becomes a white dwarf. • Despite the name, this phenomenon has nothing immediate to do with planets ...
... ejects the H and He into space as a planetary nebula. • The core left behind becomes a white dwarf. • Despite the name, this phenomenon has nothing immediate to do with planets ...
Corvus (constellation)
Corvus is a small constellation in the Southern Celestial Hemisphere. Its name comes from the Latin word ""raven"" or ""crow"". It includes only 11 stars with brighter than 4.02 magnitudes. One of the 48 constellations listed by the 2nd-century astronomer Ptolemy, it remains one of the 88 modern constellations. The four brightest stars, Gamma, Delta, Epsilon, and Beta Corvi from a distinctive quadrilateral in the night sky. The young star Eta Corvi has been found to have two debris disks.