Photometric catalog of nearby globular clusters
... Abstract. In this paper we present the second and final part of a large and photometrically homogeneous CCD color-magnitude diagram (CMD) data base, comprising 52 nearby Galactic globular clusters (GGC) imaged in the V and I bands. The catalog has been collected using only two telescopes (one for ea ...
... Abstract. In this paper we present the second and final part of a large and photometrically homogeneous CCD color-magnitude diagram (CMD) data base, comprising 52 nearby Galactic globular clusters (GGC) imaged in the V and I bands. The catalog has been collected using only two telescopes (one for ea ...
Astronomy Astrophysics IRAS 18357-0604 – an analogue of the galactic yellow hypergiant
... ∼4700–4950 Å region of the same spectrum (and also that of Klochkova et al. 2002). Given that these transitions are weaker in IRAS 1835−06 one might infer a slightly earlier spectral type for it than IRC +10420 (∼A0-2). This would also be consistent with the near-IR spectroscopic properties; the lac ...
... ∼4700–4950 Å region of the same spectrum (and also that of Klochkova et al. 2002). Given that these transitions are weaker in IRAS 1835−06 one might infer a slightly earlier spectral type for it than IRC +10420 (∼A0-2). This would also be consistent with the near-IR spectroscopic properties; the lac ...
A Study of Herbig Ae Be Star HD 163296: Variability in
... Herbig Ae Be stars (HAeBes) are intermediate mass, pre-main sequence stars which have strong emission lines in the near-infrared (NIR). These young stars range between 2-10 solar masses and have a spectral type of A or B indicated by their temperature (Herbig, 1960). HAeBes will evolve to become mai ...
... Herbig Ae Be stars (HAeBes) are intermediate mass, pre-main sequence stars which have strong emission lines in the near-infrared (NIR). These young stars range between 2-10 solar masses and have a spectral type of A or B indicated by their temperature (Herbig, 1960). HAeBes will evolve to become mai ...
Formation of millisecond pulsars with CO white dwarf companions–I
... is the mass of the neutron star; and a is the final orbital separation after the CE phase. Strictly speaking, when considering the energy budget the ‘effective efficiency parameter’ should also include the excess energy of the ejected matter at infinity – although this effect is probably small. Rece ...
... is the mass of the neutron star; and a is the final orbital separation after the CE phase. Strictly speaking, when considering the energy budget the ‘effective efficiency parameter’ should also include the excess energy of the ejected matter at infinity – although this effect is probably small. Rece ...
discovery of four new massive and dense cold cores
... single-dish telescopes have shown that massive stars form in regions of molecular gas with distinctive physical parameters, which we refer to as massive dense cores.1 For example, from observations of the CS (5 ! 4) line emission toward massive star–forming regions associated with H2O masers, Plume ...
... single-dish telescopes have shown that massive stars form in regions of molecular gas with distinctive physical parameters, which we refer to as massive dense cores.1 For example, from observations of the CS (5 ! 4) line emission toward massive star–forming regions associated with H2O masers, Plume ...
Stellar contents and star formation in the young open cluster Stock 8
... SFRs (such as ρ Oph, IC 348, Trapezium) although there is a large difference in stellar densities. On the other hand Hillenbrand (1997) found a few SFRs with unusual IMFs. The lack of strong evidence for IMF variations suggests that its fundamental form may be universal. Consequently, local conditio ...
... SFRs (such as ρ Oph, IC 348, Trapezium) although there is a large difference in stellar densities. On the other hand Hillenbrand (1997) found a few SFRs with unusual IMFs. The lack of strong evidence for IMF variations suggests that its fundamental form may be universal. Consequently, local conditio ...
Photospheric activity, rotation, and star
... drifts present in individual channels, we sum up the flux in the red, green, and blue channels to obtain a light curve in a spectral range extending from 300 to 1100 nm. The observations and data processing are described by Fridlund et al. (2010), to whom we refer the reader for details. The reducti ...
... drifts present in individual channels, we sum up the flux in the red, green, and blue channels to obtain a light curve in a spectral range extending from 300 to 1100 nm. The observations and data processing are described by Fridlund et al. (2010), to whom we refer the reader for details. The reducti ...
Research paper
... at all orientations from the dynamical ejection center shows similar behavior. The typical radial-velocity gradients range from less than 200 to over 2,000 km s−1 per parsec. In some, such as the 4000 -long streamer shown in lower-right of Figure 5, the line-brightness peaks near the high-velocity e ...
... at all orientations from the dynamical ejection center shows similar behavior. The typical radial-velocity gradients range from less than 200 to over 2,000 km s−1 per parsec. In some, such as the 4000 -long streamer shown in lower-right of Figure 5, the line-brightness peaks near the high-velocity e ...
Identification of the optical counterparts of high-mass X
... colour-colour diagram restricts the possible candidates to a handful of sources (sometimes just one or two), hence making narrow-slit spectroscopy useful. The next step is to obtain Hα spectra of those potential candidates. In order to check for the usefulness of the diagram and secure our method we ...
... colour-colour diagram restricts the possible candidates to a handful of sources (sometimes just one or two), hence making narrow-slit spectroscopy useful. The next step is to obtain Hα spectra of those potential candidates. In order to check for the usefulness of the diagram and secure our method we ...
Research Report for 2015/2016
... and a team of scientists and students from Rice and Lowell Observatory continued a search for radial velocity perturbations that might be caused by planets around young stars. Sensitive searches for older planets have turned up many such objects, but finding them around young stars is difficult beca ...
... and a team of scientists and students from Rice and Lowell Observatory continued a search for radial velocity perturbations that might be caused by planets around young stars. Sensitive searches for older planets have turned up many such objects, but finding them around young stars is difficult beca ...
The (galaxy-wide) IMF in giant elliptical galaxies: from top to bottom
... An independent test of the shape of the IMF of massive ETGs comes from the stellar remnants of the population. The assumption of a time-independent, bottom-heavy IMF naturally leads to a low number of low-mass X-ray binaries (LMXBs). As these systems consist of a neutron star and a low-mass companio ...
... An independent test of the shape of the IMF of massive ETGs comes from the stellar remnants of the population. The assumption of a time-independent, bottom-heavy IMF naturally leads to a low number of low-mass X-ray binaries (LMXBs). As these systems consist of a neutron star and a low-mass companio ...
Atmospheric characterization of Proxima b by coupling the SPHERE
... More generally, it is expected that the ongoing/upcoming transit searches (TESS, CHEOPS, PLATO, NGTS, MEarth, TRAPPIST, SPECULOOS, ExTrA) will find most of the nearest transiting systems in the next few years, opening a new era of atmospheric characterization with e.g. the James Webb Space Telescope ...
... More generally, it is expected that the ongoing/upcoming transit searches (TESS, CHEOPS, PLATO, NGTS, MEarth, TRAPPIST, SPECULOOS, ExTrA) will find most of the nearest transiting systems in the next few years, opening a new era of atmospheric characterization with e.g. the James Webb Space Telescope ...
Archetypal Cosmology: Past and Present
... of Greek myth (gods as archetypes), the ritual illuminations of the mystery religions (cosmos as divine revelation), and the Pythagorean disclosure of a universe whose unitive order was at once mathematical and numinous. For the Platonic– Pythagorean tradition, to align with the archetypal order of ...
... of Greek myth (gods as archetypes), the ritual illuminations of the mystery religions (cosmos as divine revelation), and the Pythagorean disclosure of a universe whose unitive order was at once mathematical and numinous. For the Platonic– Pythagorean tradition, to align with the archetypal order of ...
as a PDF
... the inferred circumstellar masses of dust and gas surrounding classical T-Tauri Stars (cTTSs), measured by millimeter continuum observations, preclude a simple spherical distribution of the circumstellar material about such stars (Rydgren et al. 1982). The mass involved would, if spherically distrib ...
... the inferred circumstellar masses of dust and gas surrounding classical T-Tauri Stars (cTTSs), measured by millimeter continuum observations, preclude a simple spherical distribution of the circumstellar material about such stars (Rydgren et al. 1982). The mass involved would, if spherically distrib ...
Evolution and fate of very massive stars
... very massive stars, we calculated a new grid of models for such objects, for solar, LMC and SMC metallicities, which covers the initial mass range from 120 to 500 M . Both rotating and non-rotating models were calculated using the Geneva stellar evolution code and evolved until at least the end of ...
... very massive stars, we calculated a new grid of models for such objects, for solar, LMC and SMC metallicities, which covers the initial mass range from 120 to 500 M . Both rotating and non-rotating models were calculated using the Geneva stellar evolution code and evolved until at least the end of ...
Characterizing the Cool KOIs III. KOI
... Paper 1), we acquired a K-band spectrum of KOI 961 as part of a survey of low-mass KOIs. The spectrum confirmed that it is a dwarf and not a giant based on the shallowness of the CO absorption band, and we reported an effective temperature of 3200 ± 50 K and an overall metallicity ([M/H]) of -0.33 ± ...
... Paper 1), we acquired a K-band spectrum of KOI 961 as part of a survey of low-mass KOIs. The spectrum confirmed that it is a dwarf and not a giant based on the shallowness of the CO absorption band, and we reported an effective temperature of 3200 ± 50 K and an overall metallicity ([M/H]) of -0.33 ± ...
Chapter 7 in the LSST Science Book
... interpretation of local data within a larger context: the stars that make galaxies are expected to form within dark matter halos that are themselves growing through gravitational collapse and mergers. In fact, we are very fortunate to live in a hierarchical Universe where the LV galaxies contain the ...
... interpretation of local data within a larger context: the stars that make galaxies are expected to form within dark matter halos that are themselves growing through gravitational collapse and mergers. In fact, we are very fortunate to live in a hierarchical Universe where the LV galaxies contain the ...
PPT
... •The distance to NGC is 80 million light years, which Mkn 205 is 14 times farther away at a distance of 1 billion light year. •The very distant quasar is nearly as bright as the much closer galaxy. The extraordinary brightness of quasars, which is a blending of the term quasi-stellar radio source, i ...
... •The distance to NGC is 80 million light years, which Mkn 205 is 14 times farther away at a distance of 1 billion light year. •The very distant quasar is nearly as bright as the much closer galaxy. The extraordinary brightness of quasars, which is a blending of the term quasi-stellar radio source, i ...
Link
... most massive members have later spectral types can identify locales where stars formed more than 40 Myr ago. The mass spectra, locations, velocities, and ages of young stars and the properties of gas in nearby associations provide clues about the history of star formation and the origin, evolution, ...
... most massive members have later spectral types can identify locales where stars formed more than 40 Myr ago. The mass spectra, locations, velocities, and ages of young stars and the properties of gas in nearby associations provide clues about the history of star formation and the origin, evolution, ...
VLT observations of GRS 1915+ 105
... still a matter of debate. The strong interstellar absorption towards the source, that implies optical extinctions of AV ∼ 27 magnitudes (Chaty et al. 1996), appears as the main cause of this uncertainty. Therefore, it is not surprising that the best approaches to the problem have come from imaging a ...
... still a matter of debate. The strong interstellar absorption towards the source, that implies optical extinctions of AV ∼ 27 magnitudes (Chaty et al. 1996), appears as the main cause of this uncertainty. Therefore, it is not surprising that the best approaches to the problem have come from imaging a ...
EXPLORING STELLAR EVOLUTION MODELS OF sdB STARS
... Stellar evolution calculations have had great success reproducing the observed atmospheric properties of different classes of stars. Recent detections of g-mode pulsations in evolved He burning stars allow a rare comparison of their internal structure with stellar models. Asteroseismology of subdwar ...
... Stellar evolution calculations have had great success reproducing the observed atmospheric properties of different classes of stars. Recent detections of g-mode pulsations in evolved He burning stars allow a rare comparison of their internal structure with stellar models. Asteroseismology of subdwar ...
Star Formation in the Orion Nebula II: Gas, Dust, Proplyds and
... Because of the diversity of backgrounds of the contributors to these subjects, there is an overabundance of nomenclatures and methods of indicating positions. In this article we try to use a uniform system of designation of objects and most positions of sources are indicated in 2000.0 coordinates. R ...
... Because of the diversity of backgrounds of the contributors to these subjects, there is an overabundance of nomenclatures and methods of indicating positions. In this article we try to use a uniform system of designation of objects and most positions of sources are indicated in 2000.0 coordinates. R ...
The 8190-A sodium doublet in cataclysmic variables
... part of the spectrum. This survey revealed direct spectroscopic evidence of the red dwarf in about one quarter (16) of the 65 systems surveyed. In the northern hemisphere, the survey was carried out using the 2.5-m Isaac Newton Telescope and was therefore restricted to relatively bright systems. Whe ...
... part of the spectrum. This survey revealed direct spectroscopic evidence of the red dwarf in about one quarter (16) of the 65 systems surveyed. In the northern hemisphere, the survey was carried out using the 2.5-m Isaac Newton Telescope and was therefore restricted to relatively bright systems. Whe ...
The Occurrence Rate of Small Planets Around Small Stars
... with solar α-element enhancement, masses below 1 M# , and temperatures below 7000K. We exclude models of more massive stars because solar-like stars are well-fit by the ATLAS9 models used in the construction of the KIC and it is unlikely that a star as massive as the Sun would have been assigned a t ...
... with solar α-element enhancement, masses below 1 M# , and temperatures below 7000K. We exclude models of more massive stars because solar-like stars are well-fit by the ATLAS9 models used in the construction of the KIC and it is unlikely that a star as massive as the Sun would have been assigned a t ...
S-process in extremely metal-poor, low-mass stars
... For the parametrized s-process calculations, we take constant temperature and density values typically found during the PIE. We have performed a number of calculations covering the ranges of T = 1.0−2.5 × 108 K and ρ = 100−5000 g cm−3 . In order to compute σ(AA,n) (τ), we first perform network integ ...
... For the parametrized s-process calculations, we take constant temperature and density values typically found during the PIE. We have performed a number of calculations covering the ranges of T = 1.0−2.5 × 108 K and ρ = 100−5000 g cm−3 . In order to compute σ(AA,n) (τ), we first perform network integ ...
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.