Paper II - van Werkhoven, Kenworthy and Mamajek (2014)
... period. This model is fitted to the data using the Nelder–Mead fitting algorithm (Nelder & Mead 1965). Our analysis shows that the bestfitting periods and their amplitudes differ significantly from year to year (see Table 1). Furthermore, the amplitude of the variability is significantly less during ...
... period. This model is fitted to the data using the Nelder–Mead fitting algorithm (Nelder & Mead 1965). Our analysis shows that the bestfitting periods and their amplitudes differ significantly from year to year (see Table 1). Furthermore, the amplitude of the variability is significantly less during ...
Spectral Fingerprints of Earth-like Planets Around FGK Stars
... full FGK spectral range and corresponds roughly to F0V, F2V, F5V, F7V, F9V/G0V, G2V, G8V, K0V, K2V, K4V, K5V, and K7V main sequence stars (following the spectral type classification by Gray, 1992). In this paper, we use ‘‘Earth-like,’’ as applied to our models, to mean using modern Earth’s outgassin ...
... full FGK spectral range and corresponds roughly to F0V, F2V, F5V, F7V, F9V/G0V, G2V, G8V, K0V, K2V, K4V, K5V, and K7V main sequence stars (following the spectral type classification by Gray, 1992). In this paper, we use ‘‘Earth-like,’’ as applied to our models, to mean using modern Earth’s outgassin ...
Spectral modeling of nebular-phase supernovae Anders Jerkstrand Department of Astronomy
... In the coming years, the development of several robotic wide-field surveys will further increase the inflow of data, and theorists will have their hands full to analyze them. The specific aims of this thesis have been to develop state-of-the-art computational models for nebular-phase SNe, and apply ...
... In the coming years, the development of several robotic wide-field surveys will further increase the inflow of data, and theorists will have their hands full to analyze them. The specific aims of this thesis have been to develop state-of-the-art computational models for nebular-phase SNe, and apply ...
Boron Abundances Across the" Li
... Studies of Li abundances in clusters younger than the Hyades, such as Pleiades and α Per, found only a small, if any, dip in Li (Pilachowski et al. 1987, Boesgaard et al. 1988). The conclusion was that the Li reductions occurred after the stars were already on the main-sequence; it was not a pre-mai ...
... Studies of Li abundances in clusters younger than the Hyades, such as Pleiades and α Per, found only a small, if any, dip in Li (Pilachowski et al. 1987, Boesgaard et al. 1988). The conclusion was that the Li reductions occurred after the stars were already on the main-sequence; it was not a pre-mai ...
Massive close binaries, observational characteristics - UvA-DARE
... phase. We also discuss in this section the reasons for the differences between the two observed classes of High Mass X-Ray Binaries (HMXB): the 'Standard' HMXBs and the Be/X-Ray Binaries. In section 3 as an intermezzo we discuss the evidence of kicks imparted to neutron stars at birth, and the possi ...
... phase. We also discuss in this section the reasons for the differences between the two observed classes of High Mass X-Ray Binaries (HMXB): the 'Standard' HMXBs and the Be/X-Ray Binaries. In section 3 as an intermezzo we discuss the evidence of kicks imparted to neutron stars at birth, and the possi ...
Confronting Dark Matter Powered Stars with Recent Results from
... in comparison to a normal Pop III star. Dark Stars are predicted to be cooler, larger, more massive and potentially longer lived, due to their additional energy source. Using the PHOENIX atmospheric code, stellar spectra of very massive DS are calculated to search for spectral signatures of such obj ...
... in comparison to a normal Pop III star. Dark Stars are predicted to be cooler, larger, more massive and potentially longer lived, due to their additional energy source. Using the PHOENIX atmospheric code, stellar spectra of very massive DS are calculated to search for spectral signatures of such obj ...
Roche accretion of stars close to massive black holes
... Mass transfer in binary systems has been well studied for a variety of stellar components and mass ratios. This investigation is mostly focused on binary systems composed of a stellar-mass compact object and a companion star (e.g. Webbink 1985). In particular, Hjellming & Webbink (1987) and Soberman ...
... Mass transfer in binary systems has been well studied for a variety of stellar components and mass ratios. This investigation is mostly focused on binary systems composed of a stellar-mass compact object and a companion star (e.g. Webbink 1985). In particular, Hjellming & Webbink (1987) and Soberman ...
The Science case for the UV and optical cameras
... proper motions with an error of the order of (and in some cases better than) 5 microarcsec. ...
... proper motions with an error of the order of (and in some cases better than) 5 microarcsec. ...
asteroseismological study of massive zz ceti stars with
... stars populating the high-mass component are likely to have carbon–oxygen cores, formed during the stable helium burning phase in the pre-white dwarf evolution. However, evolutionary computations show that stars with stellar mass in the zero age main sequence (ZAMS) of 7 M reach stable carbon igni ...
... stars populating the high-mass component are likely to have carbon–oxygen cores, formed during the stable helium burning phase in the pre-white dwarf evolution. However, evolutionary computations show that stars with stellar mass in the zero age main sequence (ZAMS) of 7 M reach stable carbon igni ...
The two components of the evolved massive binary LZ Cephei
... Aims. We present an in-depth study of the two components of the binary system LZ Cep to constrain the effects of binarity on the evolution of massive stars. Methods. We analyzed a set of high-resolution, high signal-to-noise ratio optical spectra obtained over the orbital period of the system to perf ...
... Aims. We present an in-depth study of the two components of the binary system LZ Cep to constrain the effects of binarity on the evolution of massive stars. Methods. We analyzed a set of high-resolution, high signal-to-noise ratio optical spectra obtained over the orbital period of the system to perf ...
The extended structure of the dwarf irregular galaxy Sagittarius⋆⋆⋆
... radial range. The structure and kinematics of the neutral hydrogen provide additional and complementary information. It must be stressed that dwarf galaxies evolved in isolation should have preserved their pristine DM haloes virtually untouched, hence bearing fundamental information on their origina ...
... radial range. The structure and kinematics of the neutral hydrogen provide additional and complementary information. It must be stressed that dwarf galaxies evolved in isolation should have preserved their pristine DM haloes virtually untouched, hence bearing fundamental information on their origina ...
HS0702+ 6043: A star showing both short-period p
... variation in HS 0702+6043 is a rotating star spot. Although single sdBs do not generally rotate very rapidly, with only one possible exception (PG 1605+072, but see Kuassivi et al. 2005), the following scenario can be constructed around this possibility. Assuming that the 1 h period corresponds to t ...
... variation in HS 0702+6043 is a rotating star spot. Although single sdBs do not generally rotate very rapidly, with only one possible exception (PG 1605+072, but see Kuassivi et al. 2005), the following scenario can be constructed around this possibility. Assuming that the 1 h period corresponds to t ...
Star Formation in Disks: Spiral Arms, Turbulence, and Triggering
... Kim, & Ostriker 2006; Dobbs & Bonnell 2007). In addition, there is star-light energy, which is comparable in density to turbulence, cosmic rays, and other energies mentioned above, but is not so easily coupled to the gas. There is also ISM self-gravity, which may be considered as a source of energy ...
... Kim, & Ostriker 2006; Dobbs & Bonnell 2007). In addition, there is star-light energy, which is comparable in density to turbulence, cosmic rays, and other energies mentioned above, but is not so easily coupled to the gas. There is also ISM self-gravity, which may be considered as a source of energy ...
L17 SHELL-SHOCKED DIFFUSION MODEL FOR THE LIGHT
... We explore a simple model for the high luminosity of SN 2006gy involving photon diffusion of shock-deposited thermal energy. The distinguishing property of the model is that the large “stellar” radius of ∼160 AU required to prevent adiabatic losses is not the true stellar radius, but rather, it is t ...
... We explore a simple model for the high luminosity of SN 2006gy involving photon diffusion of shock-deposited thermal energy. The distinguishing property of the model is that the large “stellar” radius of ∼160 AU required to prevent adiabatic losses is not the true stellar radius, but rather, it is t ...
constraints on grain formation around carbon stars
... branch (AGB) carbon stars that are required for the formation of micron-sized presolar graphite grains, with and without previously formed internal crystals of titanium carbide ( TiC ). A lower mass limit of 1.1 M for stars capable of contributing grains to the solar nebula is derived. This mass li ...
... branch (AGB) carbon stars that are required for the formation of micron-sized presolar graphite grains, with and without previously formed internal crystals of titanium carbide ( TiC ). A lower mass limit of 1.1 M for stars capable of contributing grains to the solar nebula is derived. This mass li ...
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... Neutron stars are among the most exotic objects in the Universe: indeed, they present extreme and quite unique properties both in their macrophysics, controlled by the long-range gravitational and electromagnetic interactions, and in their microphysics, controlled by the short-range weak and strong ...
... Neutron stars are among the most exotic objects in the Universe: indeed, they present extreme and quite unique properties both in their macrophysics, controlled by the long-range gravitational and electromagnetic interactions, and in their microphysics, controlled by the short-range weak and strong ...
CNO and F abundances in the barium star HD 123396
... Jorissen 1988; Han et al. 1995; Karakas et al. 2000; Izzard et al. 2010). In this context, CNO elements, along with s-process elements, are key tracers of the nucleosynthesis in the previous AGB progenitor, so they provide crucial constraints on the formation mechanism. According to the mass-transfe ...
... Jorissen 1988; Han et al. 1995; Karakas et al. 2000; Izzard et al. 2010). In this context, CNO elements, along with s-process elements, are key tracers of the nucleosynthesis in the previous AGB progenitor, so they provide crucial constraints on the formation mechanism. According to the mass-transfe ...
Asymptotic Giant Branch stars viewed up-close and far-off
... and 14 N and 13 C to the surface. The change in the surface abundance ratio of 12 C/13 C is from ≈ 90 to ≈ 20 (Charbonnel 1994). The helium core continues to contract. Eventually, helium ignites through the triple-alpha process. Pressure and temperature are independent of each other in the degenerat ...
... and 14 N and 13 C to the surface. The change in the surface abundance ratio of 12 C/13 C is from ≈ 90 to ≈ 20 (Charbonnel 1994). The helium core continues to contract. Eventually, helium ignites through the triple-alpha process. Pressure and temperature are independent of each other in the degenerat ...
The evolution of Red Supergiants to supernova in the LMC cluster
... be small compared to the age of the cluster. Hence, we can assume that all stars currently in the RSG phase had the same initial mass to within a few tenths of a solar mass. Since the stars’ masses are so similar, they will all follow almost the same path across the H-R diagram. Differences in lumin ...
... be small compared to the age of the cluster. Hence, we can assume that all stars currently in the RSG phase had the same initial mass to within a few tenths of a solar mass. Since the stars’ masses are so similar, they will all follow almost the same path across the H-R diagram. Differences in lumin ...
Complete set of notes, one file
... Almost all the astrophysical information we can derive about distant sources results from the radiation that reaches us from them. Our starting point is, therefore, a review of the principal ways of describing radiation. (In principle, this could include polarization properties, but we neglect that ...
... Almost all the astrophysical information we can derive about distant sources results from the radiation that reaches us from them. Our starting point is, therefore, a review of the principal ways of describing radiation. (In principle, this could include polarization properties, but we neglect that ...
Astronomy Astrophysics
... In conclusion, larger samples of r-process-enhanced metalpoor stars are needed in order to make progress in our understanding of the phenomenon of r-process enhancement, investigate how common the “actinide boost” phenomenon is and what its physical reasons might be, identification of reliable chron ...
... In conclusion, larger samples of r-process-enhanced metalpoor stars are needed in order to make progress in our understanding of the phenomenon of r-process enhancement, investigate how common the “actinide boost” phenomenon is and what its physical reasons might be, identification of reliable chron ...
The Hamburg/ESO R-process Enhanced Star survey (HERES)
... In conclusion, larger samples of r-process-enhanced metalpoor stars are needed in order to make progress in our understanding of the phenomenon of r-process enhancement, investigate how common the “actinide boost” phenomenon is and what its physical reasons might be, identification of reliable chron ...
... In conclusion, larger samples of r-process-enhanced metalpoor stars are needed in order to make progress in our understanding of the phenomenon of r-process enhancement, investigate how common the “actinide boost” phenomenon is and what its physical reasons might be, identification of reliable chron ...
Evolution of low mass stars
... the chief assistant of the Royal Greenwich Observatory. In 1926 Eddington offered the first stellar model able to explain the physics behind the HRD, in his book “The Internal Constitution of the Stars” (Eddington, 1926). This model, almost entirely based on the theory of radiative transfer, describ ...
... the chief assistant of the Royal Greenwich Observatory. In 1926 Eddington offered the first stellar model able to explain the physics behind the HRD, in his book “The Internal Constitution of the Stars” (Eddington, 1926). This model, almost entirely based on the theory of radiative transfer, describ ...