Synthesis and isomerization of cyclopropanols

Dappen, G M

doi:10.31274/rtd-180814-3985

Cited by 7 publications

(9 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The resulting W parameter also increases with depth. This is in agreement with the early studies (Däppen 1983;Endal et al 1985).…”

Section: The Upper Partsupporting

confidence: 94%

Measurements of Solar Irradiance and Effective Temperature as a Probe of Solar Interior Magnetic Fields

Sofia

2001

ApJ

View full text Add to dashboard Cite

We argue that a variety of solar data suggest that the activity-cycle timescale variability of the total irradiance, is produced by structural adjustments of the solar interior. Assuming these adjustments are induced by variations of internal magnetic fields, we use measurements of the total irradiance and effective temperature over the period from 1978 to 1992, to infer the magnitude and location of the magnetic field. Using an updated stellar evolution model, which includes magnetic fields, we find that the observations can be explained by fields whose peak values range from 120k to 2.3k gauss, located in the convection zone between 0.959R ⊙ and 0.997R ⊙ , respectively. The corresponding maximal radius changes, are 17 km when the magnetic field is located at 0.959R ⊙ and 3 km when it is located at 0.997R ⊙ . At these depths, the W parameter (defined by ∆ ln R/∆ ln L, where R and L are the radius and luminosity) ranges from 0.02 to 0.006. All these predictions are consistent with helioseismology and recent measurements carried out by the MDI experiment on SOHO.

show abstract

“…The resulting W parameter also increases with depth. This is in agreement with the early studies (Däppen 1983;Endal et al 1985).…”

Section: The Upper Partsupporting

confidence: 94%

Measurements of Solar Irradiance and Effective Temperature as a Probe of Solar Interior Magnetic Fields

Sofia

2001

ApJ

View full text Add to dashboard Cite

show abstract

“…This would yield ∆R/R < 3 × 10 −6 and W < 0.003 as the ratio of radius to luminosity variation. Such a small value should favor models involving changes in the outer layers to explain the observed luminosity variations (Gough 1981;Däppen 1983;Balmforth, Gough & Merryfield 1996;Gough 2001). Of course, the value of W in these models is determined by radius variation at the photosphere, while f-modes are sensitive to variations at depths of about 1-12 Mm.…”

Section: Discussionmentioning

confidence: 99%

Does the Sun Shrink with Increasing Magnetic Activity?

Antia¹

2003

ApJ

View full text Add to dashboard Cite

It has been demonstrated that frequencies of f-modes can be used to estimate the solar radius to a good accuracy. These frequencies have been used to study temporal variations in the solar radius with conflicting results. The variation in f-mode frequencies is more complicated than what is assumed in these studies. If a careful analysis is performed then it turns out that there is no evidence for any variation in the solar radius.

show abstract

“…The hydrogen molecules H2 and H + 2 are included as the only molecules, and non-ideal interactions leading to pressure ionization are treated in detail, as are degenerate electrons. Furthermore, thermodynamic consistency (that the Maxwell relations are obeyed) is ensured by the use of the free energy minimisation procedure (Däppen 1980), which was also a motivation for the EOS update. The EOS tables were custom calculated for a 15 element mixture (as opposed to the normal 6), to correspond to what is included in the Uppsala package.…”

Section: The 3d Convection Simulationsmentioning

confidence: 99%

Improvements to stellar structure models, based on a grid of 3D convection simulations – I. T(τ) relations

Trampedach

Stein

Christensen‐Dalsgaard

et al. 2014

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

Relations between temperature, T , and optical depth, τ , are often used for describing the photospheric transition from optically thick to optically thin in stellar structure models. We show that this is well justified, but also that currently used T (τ )-relations are often inconsistent with their implementation. As an outer boundary condition on the system of stellar structure equations, T (τ )-relations have an undue effect on the overall structure of stars. In this age of precision asteroseismology, we need to reassess both the method for computing and for implementing T (τ )-relations, and the assumptions they rest on.We develop a formulation for proper and consistent evaluation of T (τ )-relations from arbitrary 1D or 3D stellar atmospheres, and for their implementation in stellar structure and evolution models.We extract radiative T (τ )-relations, as described by our new formulation, from 3D simulations of convection in deep stellar atmospheres of late-type stars from dwarfs to giants. These simulations employ realistic opacities and equation of state, and account for line-blanketing. For comparison, we also extract T (τ )-relations from 1D MARCS model atmospheres using the same formulation.T (τ )-relations from our grid of 3D convection simulations display a larger range of behaviours with surface gravity, compared with those of conventional theoretical 1D hydrostatic atmosphere models based on the mixing-length theory for convection. The 1D atmospheres show little dependence on gravity. 1D atmospheres of mainsequence stars also show an abrupt transition to the diffusion approximation at τ ≃ 2.5, whereas the 3D simulations exhibit smooth transitions that occur at the same depth for M ≃ 0.8 M ⊙ , and higher in the atmosphere for both more and less massive main-sequence stars. Based on these results, we recommend no longer to use scaled solar T (τ )-relations.Files with T (τ )-relations for our grid of simulations are made available to the community, together with routines for interpolating in this irregular grid. We also provide matching tables of atmospheric opacity, for consistent implementation in stellar structure models.

show abstract

Synthesis and isomerization of cyclopropanols

Cited by 7 publications

References 0 publications

Measurements of Solar Irradiance and Effective Temperature as a Probe of Solar Interior Magnetic Fields

Measurements of Solar Irradiance and Effective Temperature as a Probe of Solar Interior Magnetic Fields

Does the Sun Shrink with Increasing Magnetic Activity?

Improvements to stellar structure models, based on a grid of 3D convection simulations – I. T(τ) relations

Contact Info

Product

Resources

About