determination of the distance to the galactic centre nigel clayton
... around an extremely compact high mass. Ghez et al. (2008, fig. 9) found that if Sgr A* is accepted to be moving then the orbit is open. The derived value then changes from Ro = 8.4 0.4 kpc to Ro = 8.0 0.6 kpc. In the Galactic centre region, helical motion is known to occur on different scales. ...
... around an extremely compact high mass. Ghez et al. (2008, fig. 9) found that if Sgr A* is accepted to be moving then the orbit is open. The derived value then changes from Ro = 8.4 0.4 kpc to Ro = 8.0 0.6 kpc. In the Galactic centre region, helical motion is known to occur on different scales. ...
SN 2006gy: DISCOVERY OF THE MOST LUMINOUS
... However, there are reasons to suspect that the mass-loss properties of stars in the local universe may not be so different from these early stars. Namely, recent studies of line-driven winds from O-type stars and WR stars have shown that their winds are highly clumped, requiring that their mass-loss ...
... However, there are reasons to suspect that the mass-loss properties of stars in the local universe may not be so different from these early stars. Namely, recent studies of line-driven winds from O-type stars and WR stars have shown that their winds are highly clumped, requiring that their mass-loss ...
Stellar activity in exoplanet hosts Enrique Herrero Casas
... Most of the efforts on the search and characterization of Earth-like exoplanets are currently focused on low mass stars. These represent the vast majority of the population in our galaxy (about 75% of the stars have a lower mass than the Sun) and their interest lies in the fact that the photometric a ...
... Most of the efforts on the search and characterization of Earth-like exoplanets are currently focused on low mass stars. These represent the vast majority of the population in our galaxy (about 75% of the stars have a lower mass than the Sun) and their interest lies in the fact that the photometric a ...
A Rotational and Variability Study of a Large Sample of... in NGC 2264 M. H. Lamm , C. A. L. Bailer-Jones
... it is possible to do this photometrically because PMS stars have strong surface magnetic fields which produce large cool spots (e. g. Feigelson & Montmerle 1999). It is often the case that the spot pattern is sufficiently asymmetric and stable that the rotation period can be found by photometric mon ...
... it is possible to do this photometrically because PMS stars have strong surface magnetic fields which produce large cool spots (e. g. Feigelson & Montmerle 1999). It is often the case that the spot pattern is sufficiently asymmetric and stable that the rotation period can be found by photometric mon ...
Circumstellar Material in Young Stellar Objects
... that a young star remains nearly constant in brightness with increasing temperature as it contracts towards the main sequence. Later, Hayashi (1961) pointed out that these evolutionary tracks were incomplete since they assumed the star would be fully radiative until the onset of core hydrogen burnin ...
... that a young star remains nearly constant in brightness with increasing temperature as it contracts towards the main sequence. Later, Hayashi (1961) pointed out that these evolutionary tracks were incomplete since they assumed the star would be fully radiative until the onset of core hydrogen burnin ...
CHEMICAL ABUNDANCE DISTRIBUTIONS OF GALACTIC HALOS
... unique set of stellar populations dictated by its own cosmologically motivated mass accretion history, which in turn determines its star formation history and subsequent chemical evolution. We then give each star particle in the satellite a set of chemical abundances ([ Fe/ H ] and [/ Fe]) drawn at ...
... unique set of stellar populations dictated by its own cosmologically motivated mass accretion history, which in turn determines its star formation history and subsequent chemical evolution. We then give each star particle in the satellite a set of chemical abundances ([ Fe/ H ] and [/ Fe]) drawn at ...
A Legacy Study of Stellar Life Cycles in the Galactic Center
... • Microquasars and some pulsars might have required luminosity and hard spectrum in high state • Fluorescent line seen in Sgr B2, Sgr C, and central parsecs of Galaxy, so would need multiple microquasars, such as GRS 1915+10, but none of them would currently be bright. • Need sources that are bright ...
... • Microquasars and some pulsars might have required luminosity and hard spectrum in high state • Fluorescent line seen in Sgr B2, Sgr C, and central parsecs of Galaxy, so would need multiple microquasars, such as GRS 1915+10, but none of them would currently be bright. • Need sources that are bright ...
Stellar Mass Loss in Globular - Jodrell Bank Centre for Astrophysics
... 47 Tucanae and ω Centauri, finding 47 Tuc V1 (and possibly V18) and ω Cen V6 surrounded by circumstellar silicate dust. ω Cen V42 may also be surrounded by carbon-rich dust. Much of this work is devoted to finding the threshold for dust production and the mass-loss rates from cluster stars with both c ...
... 47 Tucanae and ω Centauri, finding 47 Tuc V1 (and possibly V18) and ω Cen V6 surrounded by circumstellar silicate dust. ω Cen V42 may also be surrounded by carbon-rich dust. Much of this work is devoted to finding the threshold for dust production and the mass-loss rates from cluster stars with both c ...
The ROSAT galactic plane survey: ASTRONOMY AND
... a low galactic latitude region selected from the ROSAT all-sky survey. The test field is centered at l = 90◦ , b = 0◦ and has an area of 64.5 deg2 . A total of 128 soft X-ray sources are detected above a maximum likelihood of 8. Catalogue searches and optical follow-up observations show that in this ...
... a low galactic latitude region selected from the ROSAT all-sky survey. The test field is centered at l = 90◦ , b = 0◦ and has an area of 64.5 deg2 . A total of 128 soft X-ray sources are detected above a maximum likelihood of 8. Catalogue searches and optical follow-up observations show that in this ...
Astronomy Astrophysics Kuiper belts around nearby stars &
... submm region is that measured integrated fluxes are directly proportional to the temperature and mass of the disk, due to the fact that they (in most cases) sample the Rayleigh-Jeans tail of the spectral energy distribution (SED), and that the disk can be assumed to be optically thin at these wavele ...
... submm region is that measured integrated fluxes are directly proportional to the temperature and mass of the disk, due to the fact that they (in most cases) sample the Rayleigh-Jeans tail of the spectral energy distribution (SED), and that the disk can be assumed to be optically thin at these wavele ...
Dust input from AGB stars in the Large Magellanic Cloud
... The Large Magellanic Cloud (LMC) is an ideal local laboratory to investigate dust input from stars at subsolar metallicities (ZLMC ' 0.3−0.5 Z , Russell & Dopita 1992) with evolutionary dust models. During recent years IR dust emission from stellar sources in the LMC has been extensively studied in ...
... The Large Magellanic Cloud (LMC) is an ideal local laboratory to investigate dust input from stars at subsolar metallicities (ZLMC ' 0.3−0.5 Z , Russell & Dopita 1992) with evolutionary dust models. During recent years IR dust emission from stellar sources in the LMC has been extensively studied in ...
The effects of disk building on the distributions of refractory materials
... illustrated in Fig. 1. This dissipation operates even after the collapse stage stopped, and the central star continues to accrete mass from the disk. The transport of mass through the disk also determines the thermal environments within which planetary materials are processed. The disk is generally ...
... illustrated in Fig. 1. This dissipation operates even after the collapse stage stopped, and the central star continues to accrete mass from the disk. The transport of mass through the disk also determines the thermal environments within which planetary materials are processed. The disk is generally ...
THE CHEMICAL COMPOSITION AND AGE OF THE METAL
... heaviest stable elements and the radioactive element thorium. However, the other important nuclear chronometer, uranium, has not yet been detected in that star. In this paper we present the results of an extensive series of observations regarding the metal-poor (½Fe=H ¼ 2:1) halo star BD +17 3248 ...
... heaviest stable elements and the radioactive element thorium. However, the other important nuclear chronometer, uranium, has not yet been detected in that star. In this paper we present the results of an extensive series of observations regarding the metal-poor (½Fe=H ¼ 2:1) halo star BD +17 3248 ...
An extended main-sequence turn-off in the Small
... their colour–magnitude diagrams (CMDs) shows striking similarities, especially regarding the shape of their eMSTOs. The loci of main CMD features are so similar that they can be well described, in a first approximation, by the same mean metallicity, distance and extinction. NGC 411, however, present ...
... their colour–magnitude diagrams (CMDs) shows striking similarities, especially regarding the shape of their eMSTOs. The loci of main CMD features are so similar that they can be well described, in a first approximation, by the same mean metallicity, distance and extinction. NGC 411, however, present ...
EL CVn-type binaries - Discovery of 17 helium white dwarf
... is eclipsed by a 0.945M⊙ star with an effective temperature Teff = 9370 K. The eclipsing binary star AW UMa may also contain a pre-He-WD, although the interpretation of this system is complicated by an equatorial belt of material that makes the lightcurve of this binary look like that of a W UMa-typ ...
... is eclipsed by a 0.945M⊙ star with an effective temperature Teff = 9370 K. The eclipsing binary star AW UMa may also contain a pre-He-WD, although the interpretation of this system is complicated by an equatorial belt of material that makes the lightcurve of this binary look like that of a W UMa-typ ...
DOC - IVOA
... There were two general problems that prevented the IUE Object Class system from succeeding and thereby preventing archival data users from conveniently retrieving archival information on groups of stars with common properties. One was that, owing to its simplified nature, the object class scheme int ...
... There were two general problems that prevented the IUE Object Class system from succeeding and thereby preventing archival data users from conveniently retrieving archival information on groups of stars with common properties. One was that, owing to its simplified nature, the object class scheme int ...
Astronomy Astrophysics
... derive a signal per chopper step. Due to detector transient effects, at the beginning of the observation the derived signals were systematically lower than those in the consolidated part of the measurement. We then discarded the first ∼800 s (3 OFFON transitions), and determined an average [ON–OFF] ...
... derive a signal per chopper step. Due to detector transient effects, at the beginning of the observation the derived signals were systematically lower than those in the consolidated part of the measurement. We then discarded the first ∼800 s (3 OFFON transitions), and determined an average [ON–OFF] ...
YELLOW SUPERGIANTS IN THE ANDROMEDA GALAXY (M31)
... we have color coded them for clarity; the corresponding initial mass is shown in the same color. The two solid vertical lines denote the yellow supergiant region, which we define as having effective temperatures between 4800 K and 7500 K. We see that in most cases the models predict a short pass thr ...
... we have color coded them for clarity; the corresponding initial mass is shown in the same color. The two solid vertical lines denote the yellow supergiant region, which we define as having effective temperatures between 4800 K and 7500 K. We see that in most cases the models predict a short pass thr ...
Global structure and kinematics of stellar haloes in cosmological
... (Ferland et al. 1998) that contain cooling rates as a function of density, temperature, and redshift and that account for the presence of the cosmic microwave background and photoionisation from a Haardt & Madau (2001) ionising UV/X-Ray background (see Wiersma et al. 2009a). This background is switc ...
... (Ferland et al. 1998) that contain cooling rates as a function of density, temperature, and redshift and that account for the presence of the cosmic microwave background and photoionisation from a Haardt & Madau (2001) ionising UV/X-Ray background (see Wiersma et al. 2009a). This background is switc ...
Annual Report 2012 - Max Planck Institute for Astrophysics
... instrumental activities carried out in other MaxPlanck institutes. From its inception the MPA has The Max-Planck-Institut für Astrophysik, called had an internationally-recognized numerical astrothe MPA for short, was founded in 1958 under the physics program that is unparalleled by any other direct ...
... instrumental activities carried out in other MaxPlanck institutes. From its inception the MPA has The Max-Planck-Institut für Astrophysik, called had an internationally-recognized numerical astrothe MPA for short, was founded in 1958 under the physics program that is unparalleled by any other direct ...
PHD THESIS Theory and applications for transiting extrasolar planets
... later, Johhannes Kepler discovered the planetary motion laws and at the end of 17th century, P. Laplace and E. Kant suggested the first scientific theory for planetary creation. In early 19th century, after measuring the temperature of stars, astronomers realized that stars are too hot to harbour li ...
... later, Johhannes Kepler discovered the planetary motion laws and at the end of 17th century, P. Laplace and E. Kant suggested the first scientific theory for planetary creation. In early 19th century, after measuring the temperature of stars, astronomers realized that stars are too hot to harbour li ...
REVIEW Early star-forming galaxies and the reionization of the Universe
... being intercepted by clouds of dust and hydrogen within galaxies. Astronomers desire accurate measurements of the abundance of early galaxies and the distribution of their luminosities to quantify the number of sources producing energetic photons, as well as a determination of the mixture of stars, ...
... being intercepted by clouds of dust and hydrogen within galaxies. Astronomers desire accurate measurements of the abundance of early galaxies and the distribution of their luminosities to quantify the number of sources producing energetic photons, as well as a determination of the mixture of stars, ...
17 April 2013 When Galaxies Collide Professor Carolin Crawford
... that stretch between the two galaxies to link them. The extent of the tidal tails depends on the geometry of the encounter, and they are nearly always strongly arced – although they appear completely straight if viewed edge-on to the curve. The tails develop because the gravitational force is tidal ...
... that stretch between the two galaxies to link them. The extent of the tidal tails depends on the geometry of the encounter, and they are nearly always strongly arced – although they appear completely straight if viewed edge-on to the curve. The tails develop because the gravitational force is tidal ...
PSRD: Chondrules: Important, but Possibly Unfathomable
... eventually accrete to form the inner planets. Their orbits are not circular, which gives them high relative velocities compared to the nebular gas. As a planetary embryo plows through the gas, it creates a shock in front of it (called a "bow shock"), compressing and heating the dust and gas, possibl ...
... eventually accrete to form the inner planets. Their orbits are not circular, which gives them high relative velocities compared to the nebular gas. As a planetary embryo plows through the gas, it creates a shock in front of it (called a "bow shock"), compressing and heating the dust and gas, possibl ...
Planetary nebula
A planetary nebula, often abbreviated as PN or plural PNe, is a kind of emission nebula consisting of an expanding glowing shell of ionized gas ejected from old red giant stars late in their lives. The word ""nebula"" is Latin for mist or cloud and the term ""planetary nebula"" is a misnomer that originated in the 1780s with astronomer William Herschel because when viewed through his telescope, these objects appeared to him to resemble the rounded shapes of planets. Herschel's name for these objects was popularly adopted and has not been changed. They are a relatively short-lived phenomenon, lasting a few tens of thousands of years, compared to a typical stellar lifetime of several billion years.A mechanism for formation of most planetary nebulae is thought to be the following: at the end of the star's life, during the red giant phase, the outer layers of the star are expelled by strong stellar winds. Eventually, after most of the red giant's atmosphere is dissipated, the exposed hot, luminous core emits ultraviolet radiation to ionize the ejected outer layers of the star. Absorbed ultraviolet light energises the shell of nebulous gas around the central star, appearing as a bright coloured planetary nebula at several discrete visible wavelengths.Planetary nebulae may play a crucial role in the chemical evolution of the Milky Way, returning material to the interstellar medium from stars where elements, the products of nucleosynthesis (such as carbon, nitrogen, oxygen and neon), have been created. Planetary nebulae are also observed in more distant galaxies, yielding useful information about their chemical abundances.In recent years, Hubble Space Telescope images have revealed many planetary nebulae to have extremely complex and varied morphologies. About one-fifth are roughly spherical, but the majority are not spherically symmetric. The mechanisms which produce such a wide variety of shapes and features are not yet well understood, but binary central stars, stellar winds and magnetic fields may play a role.