Discovery of extremely lead-rich subdwarfs: does heavy metal signal
... Lisker et al. 2004; Ströer et al. 2007; Hirsch & Heber 2009). Our present objective was to analyse nine SPY He-sds in greater detail and attempt to answer the question just posed. 2 O B S E RVAT I O N S The ESO SPY (Napiwotzki et al. 2001) obtained VLT/UVES spectra for 76 sdB/sdOB and 58 sdO stars ...
... Lisker et al. 2004; Ströer et al. 2007; Hirsch & Heber 2009). Our present objective was to analyse nine SPY He-sds in greater detail and attempt to answer the question just posed. 2 O B S E RVAT I O N S The ESO SPY (Napiwotzki et al. 2001) obtained VLT/UVES spectra for 76 sdB/sdOB and 58 sdO stars ...
Introduction
... which stars die depends on their original mass. In low and intermediate mass stars (∼18 M ) death is preceded by the so-called planetary nebula phase. Our Sun will become a Planetary Nebula in some 5 billion years. Because by far most stars have masses below 8 M , the planetary nebula phase must b ...
... which stars die depends on their original mass. In low and intermediate mass stars (∼18 M ) death is preceded by the so-called planetary nebula phase. Our Sun will become a Planetary Nebula in some 5 billion years. Because by far most stars have masses below 8 M , the planetary nebula phase must b ...
Latitude and Longitude - Harvard University Laboratory for
... axis, it is possible to measure latitude. Eg. Use a long stick with a rule at the end and a plumb-bob to keep the stick vertical This was used by the Polynesians to measure latitude – They would typically lie on their backs in their canoes and compare the stars at the zenith to the tops of the masts ...
... axis, it is possible to measure latitude. Eg. Use a long stick with a rule at the end and a plumb-bob to keep the stick vertical This was used by the Polynesians to measure latitude – They would typically lie on their backs in their canoes and compare the stars at the zenith to the tops of the masts ...
Magnetic fields in O-, B- and A-type stars on the main sequence
... An observational way to test whether magnetic fields on the main sequence are generated during an early phase of the star-life is to investigate the incidence and properties of pre-main sequence stars. With the aim to test the fossil origin of magnetic intermediate-mass main-sequence stars, surveys d ...
... An observational way to test whether magnetic fields on the main sequence are generated during an early phase of the star-life is to investigate the incidence and properties of pre-main sequence stars. With the aim to test the fossil origin of magnetic intermediate-mass main-sequence stars, surveys d ...
AST1100 Lecture Notes
... in this diagram. Here we will use this fact to measure distances. The HRdiagram in figure 3 has been made from stars with known distances (the stars were so close that their distance could be measured with parallax). For these stars, the absolute magnitude M (thus the luminosity, total energy emitte ...
... in this diagram. Here we will use this fact to measure distances. The HRdiagram in figure 3 has been made from stars with known distances (the stars were so close that their distance could be measured with parallax). For these stars, the absolute magnitude M (thus the luminosity, total energy emitte ...
Flatfielding chapter for Calibration Volumes
... will use the term mowing to describe these large-scale motions First, let us discuss dithering. The following discussion assumes that we can control the telescope well enough to point it to a particular sub-pixel location reliably. If that is not the case, then we should simply command the telescope ...
... will use the term mowing to describe these large-scale motions First, let us discuss dithering. The following discussion assumes that we can control the telescope well enough to point it to a particular sub-pixel location reliably. If that is not the case, then we should simply command the telescope ...
AST1100 Lecture Notes
... in this diagram. Here we will use this fact to measure distances. The HRdiagram in figure 3 has been made from stars with known distances (the stars were so close that their distance could be measured with parallax). For these stars, the absolute magnitude M (thus the luminosity, total energy emitte ...
... in this diagram. Here we will use this fact to measure distances. The HRdiagram in figure 3 has been made from stars with known distances (the stars were so close that their distance could be measured with parallax). For these stars, the absolute magnitude M (thus the luminosity, total energy emitte ...
1. This question is about some of the properties of Barnard`s star
... spectrum and temperature of a certain star are used to determine its luminosity to be approximately 5.0 1031 W. The apparent brightness of the star is 1.4 10–9 W m–2. These data can be used to determine the distance of the star from Earth. (i) ...
... spectrum and temperature of a certain star are used to determine its luminosity to be approximately 5.0 1031 W. The apparent brightness of the star is 1.4 10–9 W m–2. These data can be used to determine the distance of the star from Earth. (i) ...
Astronomy 112: The Physics of Stars Class 15 Notes: Stars Before
... These clouds are extremely cold, typically around 10 K, mainly because the CO molecules are very efficient at radiating away energy. The clouds are also very dusty, and the dust makes them opaque in the optical. We can see this very clearly by comparing images of a galaxy in optical and CO emission ...
... These clouds are extremely cold, typically around 10 K, mainly because the CO molecules are very efficient at radiating away energy. The clouds are also very dusty, and the dust makes them opaque in the optical. We can see this very clearly by comparing images of a galaxy in optical and CO emission ...
X-ray binaries
... LMXBs with NSs or BHs The latest large catalogue (Li et al. arXiv: 0707.0544) includes 187 galactic and Magellanic Clouds LMXBs with NSs and BHs as accreting components. Donors can be WDs, or normal low-mass stars (main sequence or sub-giants). Many sources are found in globular clusters. Also ther ...
... LMXBs with NSs or BHs The latest large catalogue (Li et al. arXiv: 0707.0544) includes 187 galactic and Magellanic Clouds LMXBs with NSs and BHs as accreting components. Donors can be WDs, or normal low-mass stars (main sequence or sub-giants). Many sources are found in globular clusters. Also ther ...
Exploring the Universe
... When there is enough matter, the particles fuse into nebula. This fusion is where the stars get their energy. The centers are called protostars and determine how the star starts its life. The mass may be really hot which leads to high-mass blue stars. The mass may be cool which leads to low-mass red ...
... When there is enough matter, the particles fuse into nebula. This fusion is where the stars get their energy. The centers are called protostars and determine how the star starts its life. The mass may be really hot which leads to high-mass blue stars. The mass may be cool which leads to low-mass red ...
10. The Lives of the Stars
... of heat left over from contraction. • Its luminosity gradually declines with time as it loses thermal energy. ...
... of heat left over from contraction. • Its luminosity gradually declines with time as it loses thermal energy. ...
High-precision abundances of elements in solar twin stars: Trends
... (EWs) of spectral lines by Gaussian fitting relative to pseudocontinuum regions lying within 3 Å from the line measured. These regions do not necessarily represent the true continuum, but care was taken to use the same continuum windows in all stars, so that differences in EW between stars are preci ...
... (EWs) of spectral lines by Gaussian fitting relative to pseudocontinuum regions lying within 3 Å from the line measured. These regions do not necessarily represent the true continuum, but care was taken to use the same continuum windows in all stars, so that differences in EW between stars are preci ...
Galaxies and the Universe bb
... Fate of the universe • Final fate depends on the average _______ of the universe • If the density is _____ than the critical density, then the universe would ________ • Current estimates point to _____ then the critical density and predict an _______________, or open, ...
... Fate of the universe • Final fate depends on the average _______ of the universe • If the density is _____ than the critical density, then the universe would ________ • Current estimates point to _____ then the critical density and predict an _______________, or open, ...
The Evolution of Stars - a More Detailed Picture (Chapter 8
... luminosity (Fig. 1). These are called Hayashi-tracks. In time, as the internal temperature continues to rise, ionisation is completed and the opacity drops. The convective zone recedes from the centre, and the star moves to higher effective temperatures. Slowly nuclear burning starts in the core. As ...
... luminosity (Fig. 1). These are called Hayashi-tracks. In time, as the internal temperature continues to rise, ionisation is completed and the opacity drops. The convective zone recedes from the centre, and the star moves to higher effective temperatures. Slowly nuclear burning starts in the core. As ...
Rotation Periods of Wide Binaries in the Kepler Field
... Because most of the stars that satisfy the present criteria are relatively nearby, they should be expected to have low interstellar reddening. In any case, since the two components presumably lie at the same distance, the reddening would be expected to be the same, and so will not affect Figure 1. T ...
... Because most of the stars that satisfy the present criteria are relatively nearby, they should be expected to have low interstellar reddening. In any case, since the two components presumably lie at the same distance, the reddening would be expected to be the same, and so will not affect Figure 1. T ...
MHD_of_Accretion_Disks
... and will eventually become a compact object - either a white dwarf star, a neutron star, or black hole. When the lower mass star later evolves into an expansion phase, it may be so close to the compact star that its outer atmosphere actually falls onto the compact star ...
... and will eventually become a compact object - either a white dwarf star, a neutron star, or black hole. When the lower mass star later evolves into an expansion phase, it may be so close to the compact star that its outer atmosphere actually falls onto the compact star ...
Stellar kinematics
Stellar kinematics is the study of the movement of stars without needing to understand how they acquired their motion. This differs from stellar dynamics, which takes into account gravitational effects. The motion of a star relative to the Sun can provide useful information about the origin and age of a star, as well as the structure and evolution of the surrounding part of the Milky Way.In astronomy, it is widely accepted that most stars are born within molecular clouds known as stellar nurseries. The stars formed within such a cloud compose open clusters containing dozens to thousands of members. These clusters dissociate over time. Stars that separate themselves from the cluster's core are designated as members of the cluster's stellar association. If the remnant later drifts through the Milky Way as a coherent assemblage, then it is termed a moving group.