Weakened magnetic braking as the origin of anomalously
... in these stars, which implies at least small-scale magnetic activity. The starspot properties may or may not directly reflect changes in the largescale magnetic field that governs spin-down. A change in field geometry from a simple dipole to higher-order fields could produce weakened braking18,19, a ...
... in these stars, which implies at least small-scale magnetic activity. The starspot properties may or may not directly reflect changes in the largescale magnetic field that governs spin-down. A change in field geometry from a simple dipole to higher-order fields could produce weakened braking18,19, a ...
The Formation and Survival of Discs in a Lambda
... 1994). As a result, discs contain too small a fraction of the stellar mass in comparison to observed spirals. In a limited number of cases, simulations have been able to produce individual examples of realistic disc galaxies in Λ cold dark matter (ΛCDM) universes (e.g. Abadi et al. 2003; Governato e ...
... 1994). As a result, discs contain too small a fraction of the stellar mass in comparison to observed spirals. In a limited number of cases, simulations have been able to produce individual examples of realistic disc galaxies in Λ cold dark matter (ΛCDM) universes (e.g. Abadi et al. 2003; Governato e ...
Angular momentum and the formation of stars and
... to the orbital motions of other stars, and both magnetic and gravitational forces can play important roles in this loss or redistribution of angular momentum. As will be reviewed in section 2, magnetic torques can remove angular momentum from diffuse star-forming clouds and from accreting protostars ...
... to the orbital motions of other stars, and both magnetic and gravitational forces can play important roles in this loss or redistribution of angular momentum. As will be reviewed in section 2, magnetic torques can remove angular momentum from diffuse star-forming clouds and from accreting protostars ...
SPACETIME SINGULARITIES: The STORY of BLACK HOLES
... Let us now turn to the much more complicated question of how black holes form in the universe. As we shall see below, in section A.2, there are really two kinds of black hole that we know of. The first is formed in the wake of a supernova explosion, and has a mass ranging between perhaps 3-10 solar ...
... Let us now turn to the much more complicated question of how black holes form in the universe. As we shall see below, in section A.2, there are really two kinds of black hole that we know of. The first is formed in the wake of a supernova explosion, and has a mass ranging between perhaps 3-10 solar ...
Giant Molecular Clouds in Local Group Galaxies
... if the clouds are only marginally self-gravitating, as appears to be the case judging from their appearance, half the virial value may be more appropriate. There is no clear trend of XCO with metallicity. The clouds within a galaxy are shown to have the about the same H2 surface density and differen ...
... if the clouds are only marginally self-gravitating, as appears to be the case judging from their appearance, half the virial value may be more appropriate. There is no clear trend of XCO with metallicity. The clouds within a galaxy are shown to have the about the same H2 surface density and differen ...
3. Cosmology and the Origin and Evolution of Galaxies
... some success in the measurement of optical and IR spectroscopic redshifts for a fraction of the bright mm galaxies (S850µm > 5 mJy) with reliable radio counterparts8. Radio interferometric data help refine the positions of the mm galaxies, which allows the optical and IR counterparts to be identified ...
... some success in the measurement of optical and IR spectroscopic redshifts for a fraction of the bright mm galaxies (S850µm > 5 mJy) with reliable radio counterparts8. Radio interferometric data help refine the positions of the mm galaxies, which allows the optical and IR counterparts to be identified ...
PowerPoint Presentation - 16. Properties of Stars
... • How can we learn about the lives of stars, which last millions to billions of years? • By taking observations of many stars, we can study stars in many phases of life, just as we might study how humans age by observing the humans living in a village at one time. • What two basic physical propertie ...
... • How can we learn about the lives of stars, which last millions to billions of years? • By taking observations of many stars, we can study stars in many phases of life, just as we might study how humans age by observing the humans living in a village at one time. • What two basic physical propertie ...
Homework #3, AST 1002
... can't see enough material to explain the gravity that appears to hold them together. (c) Seyfert galaxies emit spectra having broad emission lines. The correct answer(s) is(are) ____________. 28. If Hubble's constant is 50 km/sec/Mpc, an object receding from us at the rate of 5000 km/sec would be __ ...
... can't see enough material to explain the gravity that appears to hold them together. (c) Seyfert galaxies emit spectra having broad emission lines. The correct answer(s) is(are) ____________. 28. If Hubble's constant is 50 km/sec/Mpc, an object receding from us at the rate of 5000 km/sec would be __ ...
Process of Science: PreMainSequence Stellar Life Tracks on the HR
... If you watch the position of the red dot on the HR diagram as the interactive figure plays, you will see that the dot is highest — meaning the object is most luminous— when it is a protostar and therefore does not yet have internal fusion. This fact can be a little surprising, but do not forget tha ...
... If you watch the position of the red dot on the HR diagram as the interactive figure plays, you will see that the dot is highest — meaning the object is most luminous— when it is a protostar and therefore does not yet have internal fusion. This fact can be a little surprising, but do not forget tha ...
Shock interactions, turbulence and the origin of the stellar mass
... ISM of the Galaxy is seen in the neutral hydrogen (H I) gas observations such as the Canadian Galactic Plane Survey [14]. These 21 cm maps of radio emission show that the diffuse ISM is highly filamentary, and abounds in bubbles, cavities and channels carved out by radiation, winds and supernova exp ...
... ISM of the Galaxy is seen in the neutral hydrogen (H I) gas observations such as the Canadian Galactic Plane Survey [14]. These 21 cm maps of radio emission show that the diffuse ISM is highly filamentary, and abounds in bubbles, cavities and channels carved out by radiation, winds and supernova exp ...
TAKS objective 5 Earth and Space Systems
... The Sun is a Star Our sun is a medium-size yellow star. It is 4.6 billion years old. In the sun, hydrogen undergoes nuclear fusion, a process that releases vast amounts of energy. During fusion hydrogen atoms join to form helium atoms. Hydrogen fusion is the source of light, heat, and other radiati ...
... The Sun is a Star Our sun is a medium-size yellow star. It is 4.6 billion years old. In the sun, hydrogen undergoes nuclear fusion, a process that releases vast amounts of energy. During fusion hydrogen atoms join to form helium atoms. Hydrogen fusion is the source of light, heat, and other radiati ...
THE MORPHOLOGICAL DEMOGRAPHICS OF GALAXIES IN THE
... types provided by BPZ are a linear combination from a template library of SEDs. We use the CWWSB_Benitez2003 template set as described in Benítez et al. (2004). These are based on the templates from Coleman, Wu, & Weedman (1980) and Kinney et al. (1996) consisting of El, Sbc, Scd, Im, SB3, and SB2, ...
... types provided by BPZ are a linear combination from a template library of SEDs. We use the CWWSB_Benitez2003 template set as described in Benítez et al. (2004). These are based on the templates from Coleman, Wu, & Weedman (1980) and Kinney et al. (1996) consisting of El, Sbc, Scd, Im, SB3, and SB2, ...
Modelling galaxy spectra in presence of interstellar dust – II. From
... (SWIRE – Lonsdale et al. 2003) and the SIRTF Nearby Galaxies Survey (SINGS – Kennicutt et al. 2003). The IR data will increase even more with the coming ASTRO-F mission (Pearson et al. 2004) and the advent of the James Webb Space Telescope (JWST). Combined with other astronomical data bases, they pr ...
... (SWIRE – Lonsdale et al. 2003) and the SIRTF Nearby Galaxies Survey (SINGS – Kennicutt et al. 2003). The IR data will increase even more with the coming ASTRO-F mission (Pearson et al. 2004) and the advent of the James Webb Space Telescope (JWST). Combined with other astronomical data bases, they pr ...
The Milky Way disk
... Abstract / This review summarises the invited presentation I gave on the Milky Way disc. The idea underneath was to touch those topics that can be considered hot nowadays in the Galactic disk research: the reality of the thick disk, the spiral structure of the Milky Way, and the properties of the ou ...
... Abstract / This review summarises the invited presentation I gave on the Milky Way disc. The idea underneath was to touch those topics that can be considered hot nowadays in the Galactic disk research: the reality of the thick disk, the spiral structure of the Milky Way, and the properties of the ou ...
Archaeoastronomical Study of the Main Pyramids of Giza
... that time, while Alnitak, the lowest star of the Belt at its culmination, corresponded to the Khufu pyramid, the lowest one in the maps. Obviously this choice is opposite to that adopted by the cartographers of the XVII century who decided to put North on the top of their maps, a convention that we ...
... that time, while Alnitak, the lowest star of the Belt at its culmination, corresponded to the Khufu pyramid, the lowest one in the maps. Obviously this choice is opposite to that adopted by the cartographers of the XVII century who decided to put North on the top of their maps, a convention that we ...
Absolute magnitudes and kinematics of barium
... with known orbits or with variable radial-velocity, there is no substantial difference between both groups. On the other hand, McWilliam (1990) analysed several stars from the Lü list (1991) and found no heavy-element overabundances, suggesting that the Lü compilation could be ”contaminated” with ...
... with known orbits or with variable radial-velocity, there is no substantial difference between both groups. On the other hand, McWilliam (1990) analysed several stars from the Lü list (1991) and found no heavy-element overabundances, suggesting that the Lü compilation could be ”contaminated” with ...
Early-type stars in the core of the young open cluster Westerlund 2
... cluster displays significant photometric variability above 1% at the 1-σ level. The twelve brightest O-type stars are found to have spectral types between O3 and O6.5, significantly earlier than previously thought. Conclusions. The distance of the early-type stars in Westerlund 2 is established to b ...
... cluster displays significant photometric variability above 1% at the 1-σ level. The twelve brightest O-type stars are found to have spectral types between O3 and O6.5, significantly earlier than previously thought. Conclusions. The distance of the early-type stars in Westerlund 2 is established to b ...
SRMP Stars Curriculum - American Museum of Natural History
... outliers: one is close by and hot, but not on the list of brightest stars; and another is quite far away and cool, but on the list of brightest stars. Elicit that these represent a very small star, and a very large star, respectively. The worksheets include the completed versions of each plot, which ...
... outliers: one is close by and hot, but not on the list of brightest stars; and another is quite far away and cool, but on the list of brightest stars. Elicit that these represent a very small star, and a very large star, respectively. The worksheets include the completed versions of each plot, which ...
Magnetic fields in O-, B- and A-type stars on the main sequence
... Magnetic fields have first been discovered in the Sun [1] and in the chemically peculiar A-type star 78 Virginis [2]. These two stars are representative of two major groups of magnetic stars, which are directly related to the dominant mechanism of heat transport in the outer layers of the stars. For t ...
... Magnetic fields have first been discovered in the Sun [1] and in the chemically peculiar A-type star 78 Virginis [2]. These two stars are representative of two major groups of magnetic stars, which are directly related to the dominant mechanism of heat transport in the outer layers of the stars. For t ...
Draft paper (submitted to MNRAS)
... MB ∼ −16, or, equivalently, with stellar masses below 109 M⊙ ) located within ∼ 4.5 Mpc from the Local Group barycenter, but excluding the satellites of the Milky Way and Andromeda, as well as those of M81 and M82. Satellite galaxies (defined here as those within 300 kpc from any of those giant gala ...
... MB ∼ −16, or, equivalently, with stellar masses below 109 M⊙ ) located within ∼ 4.5 Mpc from the Local Group barycenter, but excluding the satellites of the Milky Way and Andromeda, as well as those of M81 and M82. Satellite galaxies (defined here as those within 300 kpc from any of those giant gala ...
Comparing stars - The Open University
... (most negative apparent visual magnitude!) of any star in the night sky. This is, as we have seen, not because it is very luminous, but because it is both fairly luminous and rather close - at 2.63 pc it's the seventh closest star after the Sun. Above the lower part of the main sequence we come firs ...
... (most negative apparent visual magnitude!) of any star in the night sky. This is, as we have seen, not because it is very luminous, but because it is both fairly luminous and rather close - at 2.63 pc it's the seventh closest star after the Sun. Above the lower part of the main sequence we come firs ...
Understanding Mass-Loss and the Late Evolution of Intermediate
... producing CFW’s? Can CFW’s be produced by single stars or is a binary companion essential? Singlestar models have invoked stellar rotation, strong magnetic fields, or both (e.g. Garcia-Segura et al 1999, Blackman et al. 2001), and binary models have invoked the angular momentum and/or the gravitatio ...
... producing CFW’s? Can CFW’s be produced by single stars or is a binary companion essential? Singlestar models have invoked stellar rotation, strong magnetic fields, or both (e.g. Garcia-Segura et al 1999, Blackman et al. 2001), and binary models have invoked the angular momentum and/or the gravitatio ...
THE N/O RATIO IN EARLY B-TYPE MAIN SEQUENCE STARS AS
... This paper is based on previous studies of MS B-stars which were published between 2000 and 2008 by Lyubimkov, et al. [8-12]. High resolution spectra for more than 100 MS B-stars were obtained [8] at two observatories, the Crimean Astrophysical Observatory and the MacDonald Observatory of the Unive ...
... This paper is based on previous studies of MS B-stars which were published between 2000 and 2008 by Lyubimkov, et al. [8-12]. High resolution spectra for more than 100 MS B-stars were obtained [8] at two observatories, the Crimean Astrophysical Observatory and the MacDonald Observatory of the Unive ...
Clusters as laboratories for the study of galaxy evolution
... “The difference in the degree of evolution between our field sample and published cluster galaxies suggests a more recent formation epoch, around z=1.5 for field galaxies compared to z>2.0 for cluster galaxies. The magnitude difference implies that the field early-type galaxies are about 2 Gyr young ...
... “The difference in the degree of evolution between our field sample and published cluster galaxies suggests a more recent formation epoch, around z=1.5 for field galaxies compared to z>2.0 for cluster galaxies. The magnitude difference implies that the field early-type galaxies are about 2 Gyr young ...
Aryabhatta Research Institute of Observational Sciences
... rates of observed species with heliocentric distance. Emission bands of NH, CN, CH, C2 , C3 and NaI were studied in these comets. It was found that with heliocentric distance, gas production rate does not vary while C2 and CN production rates show variation (Sanwal et al. 2004). ...
... rates of observed species with heliocentric distance. Emission bands of NH, CN, CH, C2 , C3 and NaI were studied in these comets. It was found that with heliocentric distance, gas production rate does not vary while C2 and CN production rates show variation (Sanwal et al. 2004). ...
H II region
An H II region is a large, low-density cloud of partially ionized gas in which star formation has recently taken place. The short-lived blue stars forged in these regions emit copious amounts of ultraviolet light that ionize the surrounding gas. H II regions—sometimes several hundred light-years across—are often associated with giant molecular clouds. The first known H II region was the Orion Nebula, which was discovered in 1610 by Nicolas-Claude Fabri de Peiresc.H II regions are named for the large amount of ionised atomic hydrogen they contain, referred to as H II, pronounced H-two by astronomers (an H I region being neutral atomic hydrogen, and H2 being molecular hydrogen). Such regions have extremely diverse shapes, because the distribution of the stars and gas inside them is irregular. They often appear clumpy and filamentary, sometimes showing bizarre shapes such as the Horsehead Nebula. H II regions may give birth to thousands of stars over a period of several million years. In the end, supernova explosions and strong stellar winds from the most massive stars in the resulting star cluster will disperse the gases of the H II region, leaving behind a cluster of birthed stars such as the Pleiades.H II regions can be seen to considerable distances in the universe, and the study of extragalactic H II regions is important in determining the distance and chemical composition of other galaxies. Spiral and irregular galaxies contain many H II regions, while elliptical galaxies are almost devoid of them. In the spiral galaxies, including the Milky Way, H II regions are concentrated in the spiral arms, while in the irregular galaxies they are distributed chaotically. Some galaxies contain huge H II regions, which may contain tens of thousands of stars. Examples include the 30 Doradus region in the Large Magellanic Cloud and NGC 604 in the Triangulum Galaxy.