Weakened magnetic braking as the origin of anomalously
... composition2,14; the observed saturation of magnetic braking in rapid rotators; and the sharp transition from slow to rapid rotation that occurs in hot stars (of greater than 6,250 K) because of their thinning convective envelopes14. Under traditional prescriptions, stars undergo braking throughout ...
... composition2,14; the observed saturation of magnetic braking in rapid rotators; and the sharp transition from slow to rapid rotation that occurs in hot stars (of greater than 6,250 K) because of their thinning convective envelopes14. Under traditional prescriptions, stars undergo braking throughout ...
1. INTRODUCTION - Institut für Theoretische Astrophysik
... emission in these lines and the observed basal Ñux emission, which had been suspected to be due to nonmagnetic (i.e., acoustic) heating operating in all late-type stars. The height dependence of the acoustic energy Ñux can be explained by the limiting strength property of the acoustic shocks and is ...
... emission in these lines and the observed basal Ñux emission, which had been suspected to be due to nonmagnetic (i.e., acoustic) heating operating in all late-type stars. The height dependence of the acoustic energy Ñux can be explained by the limiting strength property of the acoustic shocks and is ...
Spectroscopic Variability of Supergiant Star HD14134, B3Ia
... Hα profile in the spectrum of the star HD14134 had the shape of an inverse P Cygni profile (Fig.1a). Another variability pattern, where Hα appears only in weak emission (13/02/2016). The Hα line was absent in the spectra of December 29-30, 2013 and of February 15, 2016, while two carbon lines CII (λ 6 ...
... Hα profile in the spectrum of the star HD14134 had the shape of an inverse P Cygni profile (Fig.1a). Another variability pattern, where Hα appears only in weak emission (13/02/2016). The Hα line was absent in the spectra of December 29-30, 2013 and of February 15, 2016, while two carbon lines CII (λ 6 ...
Spectroscopic Variability of Supergiant Star HD14134, B3Ia
... Hα profile in the spectrum of the star HD14134 had the shape of an inverse P Cygni profile (Fig.1a). Another variability pattern, where Hα appears only in weak emission (13/02/2016). The Hα line was absent in the spectra of December 29-30, 2013 and of February 15, 2016, while two carbon lines CII (λ 6 ...
... Hα profile in the spectrum of the star HD14134 had the shape of an inverse P Cygni profile (Fig.1a). Another variability pattern, where Hα appears only in weak emission (13/02/2016). The Hα line was absent in the spectra of December 29-30, 2013 and of February 15, 2016, while two carbon lines CII (λ 6 ...
RApid Temporal Survey-RATS I: Overview and first results
... AM CVn systems. For orbital periods less than 80 min, the secondary (mass donating) star cannot be a main sequence star. Further, for periods shorter than 30 min, the secondary must be a Helium white dwarf (Rappaport, Joss & Webbink 1982). There are around 13 of these AM CVn systems currently known. ...
... AM CVn systems. For orbital periods less than 80 min, the secondary (mass donating) star cannot be a main sequence star. Further, for periods shorter than 30 min, the secondary must be a Helium white dwarf (Rappaport, Joss & Webbink 1982). There are around 13 of these AM CVn systems currently known. ...
Chapter 31
... Milky Way long before they knew what they were or if they were part of our own galaxy. • In 1924, Edwin Hubble discovered Cepheid variable stars in the Great Nebula in the Andromeda constellation. • Measuring the distance to the nebula, Hubble showed that they were much too far away to be located in ...
... Milky Way long before they knew what they were or if they were part of our own galaxy. • In 1924, Edwin Hubble discovered Cepheid variable stars in the Great Nebula in the Andromeda constellation. • Measuring the distance to the nebula, Hubble showed that they were much too far away to be located in ...
Astronomy Assignment #1
... (due West) for all observers independent of their latitude. An observer in the northern hemisphere will see the celestial equator cross the local meridian looking south, while an observer in the southern hemisphere will see the celestial equator cross the local meridian looking north. The altitude o ...
... (due West) for all observers independent of their latitude. An observer in the northern hemisphere will see the celestial equator cross the local meridian looking south, while an observer in the southern hemisphere will see the celestial equator cross the local meridian looking north. The altitude o ...
Rocky planetesimals as the origin of metals in DZ stars
... Farihi & Zuckerman 2009a). Thus, while there is firm observational evidence of pollution via circumstellar material, as yet there is none favouring the ISM. Aannestad et al. (1993) provided an extensive spatial, kinematical and calcium abundance analysis against which they tested likely scenarios of ...
... Farihi & Zuckerman 2009a). Thus, while there is firm observational evidence of pollution via circumstellar material, as yet there is none favouring the ISM. Aannestad et al. (1993) provided an extensive spatial, kinematical and calcium abundance analysis against which they tested likely scenarios of ...
High-precision abundances of elements in solar twin stars: Trends
... Gaidos (2015), who suggests that [X/Fe]-T C correlations can be explained by dust-gas segregation in circumstellar disks rather than formation of terrestrial planets. Additional information on the connection between abundance ratios in stars and the occurrence of planets may be obtained from studies ...
... Gaidos (2015), who suggests that [X/Fe]-T C correlations can be explained by dust-gas segregation in circumstellar disks rather than formation of terrestrial planets. Additional information on the connection between abundance ratios in stars and the occurrence of planets may be obtained from studies ...
SkyWatcher2017.5 1.3 Mb - Boise Astronomical Society
... luminosity distance of DL = 749 mega-parsecs may be calculated from z. It is also one of the most luminous quasars known, with an absolute magnitude of −26.7, meaning that if it were only as distant as Pollux it would appear nearly as bright in the sky as the Sun. Since the sun's absolute magnitude ...
... luminosity distance of DL = 749 mega-parsecs may be calculated from z. It is also one of the most luminous quasars known, with an absolute magnitude of −26.7, meaning that if it were only as distant as Pollux it would appear nearly as bright in the sky as the Sun. Since the sun's absolute magnitude ...
Chemical Composition and Evolutionary Status of the Ap Star HD
... directly opposite, constitutes an exception. At the same time, it should be noted that good agreement in abundances is observed from a large number of Cr I and Cr II lines. In normal stars, a difference in the abundances of an element in different ionization stages suggests an improper choice of the s ...
... directly opposite, constitutes an exception. At the same time, it should be noted that good agreement in abundances is observed from a large number of Cr I and Cr II lines. In normal stars, a difference in the abundances of an element in different ionization stages suggests an improper choice of the s ...
AR2013 - Vatican Observatory
... collaboration with colleagues and institutions in the field. NASA will provide four all-sky cameras, which should be ready by the end of 2014. NEO Observations: The major difficulty in characterizing Near Earth Objects is that they are small, faint, and fast-moving. The time from discovery to when t ...
... collaboration with colleagues and institutions in the field. NASA will provide four all-sky cameras, which should be ready by the end of 2014. NEO Observations: The major difficulty in characterizing Near Earth Objects is that they are small, faint, and fast-moving. The time from discovery to when t ...
Summary of Talks at Growing Black Holes 2004 in Garching
... stellar population, which they did by using [OIII] luminosities as a proxy of AGN luminosity. Statistics : Overall fraction of AGN in the sample >50% for nearby L* galaxies at low redshift. Fraction declines toward higher z (because of increasing stellar contamination in the 3 arcsec fiber?) The ...
... stellar population, which they did by using [OIII] luminosities as a proxy of AGN luminosity. Statistics : Overall fraction of AGN in the sample >50% for nearby L* galaxies at low redshift. Fraction declines toward higher z (because of increasing stellar contamination in the 3 arcsec fiber?) The ...
Doppler imaging of stellar surfaces
... rise to doubts about the reliability of specific types of features. The potential for generating artifacts in DI reconstructions have led some of us to run tests comparing the reconstruction of images from artificial data, where incorrect parameters have been used in the reconstruction, with the ori ...
... rise to doubts about the reliability of specific types of features. The potential for generating artifacts in DI reconstructions have led some of us to run tests comparing the reconstruction of images from artificial data, where incorrect parameters have been used in the reconstruction, with the ori ...
IAU-Perraut-2013 - Putting A Stars into Context
... Coupled with spectroscopy, optical interferometry can allow kinematics studies of A stars’ environments. Going beyong angular diameter measurements allows limbdarkening to be derived and besides surfaces of fast rotators to be ...
... Coupled with spectroscopy, optical interferometry can allow kinematics studies of A stars’ environments. Going beyong angular diameter measurements allows limbdarkening to be derived and besides surfaces of fast rotators to be ...
Cygnus X-2, super-Eddington mass transfer, and pulsar binaries
... Max-Planck-Institut fuÈr Astrophysik, Karl-Schwarzschild-Strasse 1, D±85740 Garching, Germany ...
... Max-Planck-Institut fuÈr Astrophysik, Karl-Schwarzschild-Strasse 1, D±85740 Garching, Germany ...
Chapter-by-Chapter Guide
... were on top of everything else. This suggests that the universe may have been very tiny and dense at some point in the distant past and has been expanding ever since. This beginning is what we call the Big Bang. Most of the atoms in our bodies (all the elements except for hydrogen, since our bodies ...
... were on top of everything else. This suggests that the universe may have been very tiny and dense at some point in the distant past and has been expanding ever since. This beginning is what we call the Big Bang. Most of the atoms in our bodies (all the elements except for hydrogen, since our bodies ...
Apparent Brightness, Parallax and the Distance to Sirius
... • The measured flux of light from Sirius is 1.2 X 10 – 4 ergs/ cm2 sec. From this, calculate how far away Sirius would be based on our assumption. Give your answer in cm, but then convert ...
... • The measured flux of light from Sirius is 1.2 X 10 – 4 ergs/ cm2 sec. From this, calculate how far away Sirius would be based on our assumption. Give your answer in cm, but then convert ...
Pulsed Accretion in the Young Binary &
... out to the suns and warned them that he was about to shoot. But the brothers were so spoiled, so full of their own power that they merely stared at Yi as if daring him to take action. As Yi stood there with the bowstring taut, his patience drained away. It was replaced by such a terrible anger that ...
... out to the suns and warned them that he was about to shoot. But the brothers were so spoiled, so full of their own power that they merely stared at Yi as if daring him to take action. As Yi stood there with the bowstring taut, his patience drained away. It was replaced by such a terrible anger that ...
Astrometric Reference Frame Science
... Astronomers have been discussing the intriguing possibility that the Sun has a dim companion (Nemesis) on an eccentric orbit. An astrometric mission will be able to detect any invisible gravitating body in our vicinity in an elegant way if this body is close and massive enough. Any acceleration of t ...
... Astronomers have been discussing the intriguing possibility that the Sun has a dim companion (Nemesis) on an eccentric orbit. An astrometric mission will be able to detect any invisible gravitating body in our vicinity in an elegant way if this body is close and massive enough. Any acceleration of t ...
- National Optical Astronomy Observatory
... translation stage and the number of spectral frame to collect. (Take into account that one slit width is about half an arcsecond and the diffraction limit of the telescope at 5 microns is ~0.8 arcseconds. Spatially sampling at ~0.4 arcseconds would then be about right under good seeing.) ! Input sca ...
... translation stage and the number of spectral frame to collect. (Take into account that one slit width is about half an arcsecond and the diffraction limit of the telescope at 5 microns is ~0.8 arcseconds. Spatially sampling at ~0.4 arcseconds would then be about right under good seeing.) ! Input sca ...
Origin of the Chemical Elements
... Chemical elements are central for the existence of life and the richness and variety of our environment. Therefore, one of the basic questions concerns the origin of the chemical elements. The answer is complex because it relies on dynamical processes from elementary particles and nuclei to stars an ...
... Chemical elements are central for the existence of life and the richness and variety of our environment. Therefore, one of the basic questions concerns the origin of the chemical elements. The answer is complex because it relies on dynamical processes from elementary particles and nuclei to stars an ...
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.