A Spectroscopic Survey of a Sample of Active M Dwarfs.
... interested in seeing whether other indications of youth are present. It has long been known that single M dwarfs decline in activity with age. The discovery of the TW Hydrae Association (Kastner et al. 1997; Webb et al. 1999) shows that very young stars can be found in the immediate solar neighbourh ...
... interested in seeing whether other indications of youth are present. It has long been known that single M dwarfs decline in activity with age. The discovery of the TW Hydrae Association (Kastner et al. 1997; Webb et al. 1999) shows that very young stars can be found in the immediate solar neighbourh ...
The accretion disk paradigm for young stars
... whereas the observed excess luminosity can be greater than L in extreme CTTSs. Even though the value of a typical CTTS luminosity excess was unknown in the early 1950s, it was already clear that it was orders of magnitude larger than what the accretion of interstellar cloud gas could provide. Faced ...
... whereas the observed excess luminosity can be greater than L in extreme CTTSs. Even though the value of a typical CTTS luminosity excess was unknown in the early 1950s, it was already clear that it was orders of magnitude larger than what the accretion of interstellar cloud gas could provide. Faced ...
The Classification of Stellar Spectra
... Background: The History And Nature Of Spectral Classification Patterns of absorption lines were first observed in the spectrum of the sun by the German physicist Joseph von Fraunhofer early in the 1800’s, but it was not until late in the century that astronomers were able to routinely examine the sp ...
... Background: The History And Nature Of Spectral Classification Patterns of absorption lines were first observed in the spectrum of the sun by the German physicist Joseph von Fraunhofer early in the 1800’s, but it was not until late in the century that astronomers were able to routinely examine the sp ...
SS_L1
... the influence of a (constant) gravitational acceleration equal to the surface gravity of a star of mass M tff ~ (2/3 G)-1/2 ~ 2.2 103 (R3/M)1/2 s where R and M are in solar units. ...
... the influence of a (constant) gravitational acceleration equal to the surface gravity of a star of mass M tff ~ (2/3 G)-1/2 ~ 2.2 103 (R3/M)1/2 s where R and M are in solar units. ...
Dr. Amanda Karakas and Prof. John Lattanzio
... 3. Binary evolution channels: mass loss, envelope ejection, Type Ia supernova and nova explosions ...
... 3. Binary evolution channels: mass loss, envelope ejection, Type Ia supernova and nova explosions ...
A COMPREHENSIVE COMPARISON OF THE SUN TO
... than 94% 2% of the stars in the Kroupa (2002) IMF. Fourteen brown dwarfs and nine white dwarfs within 7.1 pc were not included in this sample. Including them yields 94% — the same result obtained from the IMF. Our 95% 2% result should be compared with the 91% reported by Gonzalez (1999b). The Su ...
... than 94% 2% of the stars in the Kroupa (2002) IMF. Fourteen brown dwarfs and nine white dwarfs within 7.1 pc were not included in this sample. Including them yields 94% — the same result obtained from the IMF. Our 95% 2% result should be compared with the 91% reported by Gonzalez (1999b). The Su ...
Astrophysical explosions: from solar flares to cosmic gamma
... away and the viscous transport of mass is slow. In this state, the disc cannot transport matter through the disc and onto the white dwarf at the rate mass is added to the disc. The disc thus accumulates mass in its outer regions. Eventually, as the density increases, the disc becomes opaque (optical ...
... away and the viscous transport of mass is slow. In this state, the disc cannot transport matter through the disc and onto the white dwarf at the rate mass is added to the disc. The disc thus accumulates mass in its outer regions. Eventually, as the density increases, the disc becomes opaque (optical ...
Emergency Land Navigation
... this outer sphere as a celestial sphere. The stars are fixed upon the sphere in relation to each other and thus are called fixed stars. Out of the many stars found on the sphere, there are only 57 of them, which we consider are bright enough to help us in our navigation. Planets as a class move amon ...
... this outer sphere as a celestial sphere. The stars are fixed upon the sphere in relation to each other and thus are called fixed stars. Out of the many stars found on the sphere, there are only 57 of them, which we consider are bright enough to help us in our navigation. Planets as a class move amon ...
The Evolution of Molecular Clouds
... processes probably cannot be clearly separated in time, and they may all go on simultaneously in different parts of a star-forming complex. Two possible formation mechanisms for molecular clouds that have been considered in some detail are (1) cloud growth by random collisions and coalescence, and ( ...
... processes probably cannot be clearly separated in time, and they may all go on simultaneously in different parts of a star-forming complex. Two possible formation mechanisms for molecular clouds that have been considered in some detail are (1) cloud growth by random collisions and coalescence, and ( ...
The Gaseous Halo of NGC 891 Edmund Hodges-Kluck Joel Bregman
... • Is the X-ray metallicity wrong (cf. Li & Wang 2013)? • Are metals in the hot gas depleted onto dust? • Did a small amount of accretion trigger a large amount of star formation (halo may not be in a steady state)? • … are they unrelated? ...
... • Is the X-ray metallicity wrong (cf. Li & Wang 2013)? • Are metals in the hot gas depleted onto dust? • Did a small amount of accretion trigger a large amount of star formation (halo may not be in a steady state)? • … are they unrelated? ...
1 Introduction - Wiley-VCH
... motion of stars within ellipticals is mainly random. These objects are often called early-type galaxies. The second family is characterized by a flat disk with a spiral morphology , with the possible presence of a bar, a bulge, and a nucleus (S). These systems are undergoing episodes of star formati ...
... motion of stars within ellipticals is mainly random. These objects are often called early-type galaxies. The second family is characterized by a flat disk with a spiral morphology , with the possible presence of a bar, a bulge, and a nucleus (S). These systems are undergoing episodes of star formati ...
Testing the strong-field dynamics of general relativity with gravitional
... 0.5% deviation at (v/c)6 beyond leading order can be seen (!) Work in progress ...
... 0.5% deviation at (v/c)6 beyond leading order can be seen (!) Work in progress ...
Astronomy Astrophysics Circumstellar emission in Be/X-ray binaries of the Magellanic
... In this paper, we present a method to correctly treat these effects by means of simple correlations between the circumstellar excess in (B − V) and (V − I) colours and the amount of emission, as measured by the Hα equivalent width. To this goal, we have observed a sample of Be/X-ray binaries in the M ...
... In this paper, we present a method to correctly treat these effects by means of simple correlations between the circumstellar excess in (B − V) and (V − I) colours and the amount of emission, as measured by the Hα equivalent width. To this goal, we have observed a sample of Be/X-ray binaries in the M ...
binary stars instructor notes
... be either annular or partial. An occultation is an eclipse of star 2 by star 1 (the deeper, primary eclipse) and can be either total or partial. The exact situation depends upon the inclination of the orbit, i, and the radii of the two stars. ...
... be either annular or partial. An occultation is an eclipse of star 2 by star 1 (the deeper, primary eclipse) and can be either total or partial. The exact situation depends upon the inclination of the orbit, i, and the radii of the two stars. ...
T
... The long-term precision of the instrument cannot be checked easily because it requires a long time base on one hand, and the knowledge of stable stellar sources on the other hand. Especially the latter point represents a new challenge since the intrinsic stability of the stars has never been studied ...
... The long-term precision of the instrument cannot be checked easily because it requires a long time base on one hand, and the knowledge of stable stellar sources on the other hand. Especially the latter point represents a new challenge since the intrinsic stability of the stars has never been studied ...
A spectroscopic investigation of the O-type star - ORBi
... Moreover, the distribution of the orbital parameters provides observational clues to the way that O-type stars form and to the interactions during their evolution. Aims. Our objective is to constrain the multiplicity of a sample of O-type stars belonging to poorly investigated OB associations in the ...
... Moreover, the distribution of the orbital parameters provides observational clues to the way that O-type stars form and to the interactions during their evolution. Aims. Our objective is to constrain the multiplicity of a sample of O-type stars belonging to poorly investigated OB associations in the ...
Summary of dynamics of the regular heptagon: N =7
... D’s region spans 3 forward edges since it is step -3. This span is maximal for N = 7 so D has the largest possible measure. The development of S[1] and S[2] are similar, but complicated by the congestion of the ‘inner star’ region. In all cases the shear is the same, so the centers of these regions ...
... D’s region spans 3 forward edges since it is step -3. This span is maximal for N = 7 so D has the largest possible measure. The development of S[1] and S[2] are similar, but complicated by the congestion of the ‘inner star’ region. In all cases the shear is the same, so the centers of these regions ...
File 11 - School of Astronomy, IPM
... Stellar Astrophysics South Africa has had a long and rich history of Stellar astronomy. In 1833, the first ever measurement of the distance to a star (Alpha Centauri) was made. To continue tradition, group is working on- Transients e.g., novae and supernovae; interacting binaries e.g., cataclysmic v ...
... Stellar Astrophysics South Africa has had a long and rich history of Stellar astronomy. In 1833, the first ever measurement of the distance to a star (Alpha Centauri) was made. To continue tradition, group is working on- Transients e.g., novae and supernovae; interacting binaries e.g., cataclysmic v ...
Luminosity, Flux and Magnitudes Outline
... All objects have internal energy which is manifested by the microscopic motions of particles. There is a continuum of energy levels associated with this motion. If the object is in thermal equilibrium then it can be characterized by a single quantity, it’s temperature. An object in thermal equilibri ...
... All objects have internal energy which is manifested by the microscopic motions of particles. There is a continuum of energy levels associated with this motion. If the object is in thermal equilibrium then it can be characterized by a single quantity, it’s temperature. An object in thermal equilibri ...
Stars: Intro & Classification Astronomy 1 — Elementary Astronomy LA Mission College
... LA Mission College Spring F2015 ...
... LA Mission College Spring F2015 ...
Perseus (constellation)
Perseus, named after the Greek mythological hero Perseus, is a constellation in the northern sky. It was one of 48 listed by the 2nd-century astronomer Ptolemy and among the 88 modern constellations defined by the International Astronomical Union (IAU). It is located in the northern celestial hemisphere near several other constellations named after legends surrounding Perseus, including Andromeda to the west and Cassiopeia to the north. Perseus is also bordered by Aries and Taurus to the south, Auriga to the east, Camelopardalis to the north, and Triangulum to the west.The galactic plane of the Milky Way passes through Perseus but is mostly obscured by molecular clouds. The constellation's brightest star is the yellow-white supergiant Alpha Persei (also called Mirfak), which shines at magnitude 1.79. It and many of the surrounding stars are members of an open cluster known as the Alpha Persei Cluster. The best-known star, however, is Algol (Beta Persei), linked with ominous legends because of its variability, which is noticeable to the naked eye. Rather than being an intrinsically variable star, it is an eclipsing binary. Other notable star systems in Perseus include X Persei, a binary system containing a neutron star, and GK Persei, a nova that peaked at magnitude 0.2 in 1901. The Double Cluster, comprising two open clusters quite near each other in the sky, was known to the ancient Chinese. The constellation gives its name to the Perseus Cluster (Abell 426), a massive galaxy cluster located 250 million light-years from Earth. It hosts the radiant of the annual Perseids meteor shower—one of the most prominent meteor showers in the sky.