Selected topics in the evolution of low-mass stars

Catelan, M.

doi:10.1051/epjconf/20134301001

Cited by 8 publications

(9 citation statements)

References 87 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…5.4), the error associated to the iron abundance σ [Fe/H] = ±0.036 dex translates into an error in the global metallicity of σ Z = ±0.00011. However, the uncertainty in the solar metallicity proper (see Catelan 2013, for a review and references) also adds up to the budget, leading to a final uncertainty estimate in Z of ±0.00035. The impact of variations in Z at this level upon the TRGB position is shown in Fig.…”

Section: Iron Abundancementioning

confidence: 99%

“…But as the luminosity of the TRGB is regulated mainly by the degenerate He core, one expects that uncertainties in the radiative opacities κ rad are not of primary importance for the evolution close to the TRGB. The current best estimates of uncertainties in κ rad tend to fall around the 5% level, but there have been suggestions, raised primarily in the framework of the so-called "solar abundance problem," that the uncertainties in κ rad may be higher, possibly reaching up to 20-30% at some points in the stellar interior (see Catelan 2013 for a recent review and references).…”

Section: Radiative Opacitiesmentioning

confidence: 99%

See 1 more Smart Citation

Particle-physics constraints from the globular cluster M5: neutrino dipole moments

Viaux

Catelan

Stetson

et al. 2013

A&A

Self Cite

105

144

View full text Add to dashboard Cite

Stellar evolution is modified if energy is lost in a "dark channel" similar to neutrino emission. Comparing modified stellar evolution sequences with observations provides some of the most restrictive limits on axions and other hypothetical low-mass particles and on non-standard neutrino properties. In particular, a putative neutrino magnetic dipole moment µ ν enhances the plasmon decay process, postpones helium ignition in low-mass stars, and therefore extends the red-giant branch (RGB) in globular clusters (GCs). The brightness of the tip of the RGB (TRGB) remains the most sensitive probe for µ ν and we revisit this argument from a modern perspective. Based on a large set of archival observations, we provide high-precision photometry for the Galactic GC M5 (NGC 5904) and carefully determine its TRGB position. On the theoretical side, we add the extra plasmon decay rate brought about by µ ν to the Princeton-Goddard-PUC (PGPUC) stellar evolution code. Different sources of uncertainty are critically examined. The main source of systematic uncertainty is the bolometric correction and the main statistical uncertainty derives from the distance modulus based on main-sequence fitting. (Other measures of distance, e.g., the brightness of RR Lyrae stars, are influenced by the energy loss that we wish to constrain.) The statistical uncertainty of the TRGB position relative to the brightest RGB star is less important because the RGB is well populated. We infer an absolute I-band brightness of M I = −4.17±0.13 mag for the TRGB compared with the theoretical prediction of −3.99 ± 0.07 mag, in reasonable agreement with each other. A significant brightness increase caused by neutrino dipole moments is constrained such that µ ν < 2.6 × 10 −12 µ B (68% CL), where µ B ≡ e/2m e is the Bohr magneton, and µ ν < 4.5 × 10 −12 µ B (95% CL). In these results, statistical and systematic errors have been combined in quadrature.

show abstract

Section: Iron Abundancementioning

confidence: 99%

Section: Radiative Opacitiesmentioning

confidence: 99%

Particle-physics constraints from the globular cluster M5: neutrino dipole moments

Viaux

Catelan

Stetson

et al. 2013

A&A

Self Cite

105

144

View full text Add to dashboard Cite

show abstract

“…During the last 70 years, significant progress has been achieved in the study of the physics in the interior of the Sun and stars. 24,48,96 This advance has been possible due to the great development of several key fields of experimental and theoretical physics, such as statistical physics, magneto-hydrodynamics, particle physics, and nuclear physics, among others. Astronomers are now able to describe with highprecision the physics that takes place inside stars like the Sun, as well as many other classes of stars, with masses different than that of the Sun, and in quite different stages of stellar evolution.…”

Section: Introductionmentioning

confidence: 99%

The Sun and stars: Giving light to dark matter

Casanellas

Lopes

2014

Mod. Phys. Lett. A

View full text Add to dashboard Cite

During the last century, with the development of modern physics in such diverse fields as thermodynamics, statistical physics, and nuclear and particle physics, the basic principles of the evolution of stars have been successfully well understood. Nowadays, a precise diagnostic of the stellar interiors is possible with the new fields of helioseismology and astroseismology. Even the measurement of solar neutrino fluxes, once a problem in particle physics, is now a powerful probe of the core of the Sun. These tools have allowed the use of stars to test new physics, in particular the properties of the hypothetical particles that constitute the dark matter of the Universe. Here we present recent results obtained using this approach

show abstract

“…Comparison with the case of M3 (NGC 5272) may also offer some hints in this regard (Catelan 2013). M3, like M4, also possesses well-developed RHB and BHB components.…”

Section: Introductionmentioning

confidence: 87%

“…With the discovery of the multiple main sequences in ω Centauri (NGC 5139; Bedin et al 2004;Bellini et al 2009, 1 (Norris 2004;D'Antona et al 2005;Piotto et al 2005Piotto et al , 2007, the inclusion of the initial helium abundance (Y ) as a free parameter in low-mass stellar evolutionary calculations has again become popular, since variations in the helium abundance, due to its well-known impact upon main-sequence stars (e.g., Demarque 1967;Iben & Faulkner 1968;Simoda & Iben 1968, 1970, can produce the observed split main sequence loci (e.g., Norris 2004;Piotto et al 2005). From a nuclear astrophysics perspective, such He abundance variations appear rather appealing, since the O-Na and Mg-Al variations occur naturally in the process of proton-capture nucleosynthesis, even though -importantly -the actual level of accompanying He enhancement remains unclear at present (see Catelan 2013, for a recent review and references).…”

Section: Introductionmentioning

confidence: 99%

Constraints on Helium Enhancement in the Globular Cluster M4 (Ngc 6121): The Horizontal Branch Test

Valcarce

Catelan

Alonso-García

et al. 2014

ApJ

Self Cite

View full text Add to dashboard Cite

Recent pieces of evidence have revealed that most, and possibly all, globular star clusters are composed of groups of stars that formed in multiple episodes with different chemical compositions. In this sense, it has also been argued that variations in the initial helium abundance (Y ) from one population to the next are also the rule, rather than the exception. In the case of the metal-intermediate globular cluster M4 (NGC 6121), recent highresolution spectroscopic observations of blue horizontal branch (HB) stars (i.e., HB stars hotter than the RR Lyrae instability strip) suggest that a large fraction of blue HB stars are second-generation stars formed with high helium abundances. In this paper, we test this scenario by using recent photometric and spectroscopic data together with theoretical evolutionary computations for different Y values. Comparing the photometric data with the theoretically-derived color-magnitude diagrams, we find that the bulk of the blue HB stars in M4 have ∆Y 0.01 with respect to the cluster's red HB stars (i.e., HB stars cooler than the RR Lyrae strip) -a result which is corroborated by comparison with spectroscopically derived gravities and temperatures, which also favor little He enhancement. However, the possible existence of a minority population on the blue HB of the cluster with a significant He enhancement level is also discussed.

show abstract

Selected topics in the evolution of low-mass stars

Cited by 8 publications

References 87 publications

Particle-physics constraints from the globular cluster M5: neutrino dipole moments

Particle-physics constraints from the globular cluster M5: neutrino dipole moments

The Sun and stars: Giving light to dark matter

Constraints on Helium Enhancement in the Globular Cluster M4 (Ngc 6121): The Horizontal Branch Test

Contact Info

Product

Resources

About