getTrk {stellaR}

Import stellar track data

Description

Import a stellar evolutionary track from pre-main sequence to He flash and from ZAHB to thermal pulses.

Usage

 getTrk(m, z, y, ml, afe,
          baseURL="ftp://cdsarc.u-strasbg.fr/pub/cats/J/A+A/540/A26/")
 getHb(m, z, y, ml, afe,
         baseURL="ftp://cdsarc.u-strasbg.fr/pub/cats/J/A+A/540/A26/")
     

Arguments

m

the mass, in unit of solar mass, of the model to get. Allowed values are 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.00, 1.05, 1.10.

z

the initial metallicity of the model to get. Allowed values are 0.0001, 0.0002, 0.0003, 0.0004, 0.0005, 0.0006, 0.0007, 0.0008, 0.0009, 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, 0.01.

y

the initial helium abundance of the model to get. Allowed values are 0.25, 0.27, 0.33, 0.38, 0.42.

ml

the mixing-length of the model to get. Allowed values are 1.7, 1.8, 1.9.

afe

the alpha-enhanchment of the model to get. It can be one of afe = 0 for [alpha/Fe] = 0.0 or afe = 1 for [alpha/Fe] = 0.3.

baseURL

the URL of the base directory of the database from where get the models. See Details for further information.

Details

As a sanity check, the function performs a consistency test on the parameters z, y, ml, afe by a call to testComposition.

By default the function requires an Internet access for data gathering. Tracks and isochrones are downloaded from the on-line repository CDS (http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/540/A26). It is also possible to gather data from a local download of the catalog, specifying as baseURL the root directory of the download. In this case the structure of the catalog and the names of files and directory must be preserved.

Value

getTrk returns an object of class trk; getHb returns an object of class hb.

More specifically these objects are lists with common elements:

mass

the mass of the model (in unit of solar mass)

z

the metallicity of the model

y

the initial helium content of the model

ml

the mixing-length value of the model

alpha.enh

the alpha-enhanchment of the model. It can be one of alpha.enh = 0 for [alpha/Fe] = 0.0 or alpha.enh = 1 for [alpha/Fe] = 0.3.

data

the dataset of stellar track, containing the following variables:

mod

model number

time

logarithm of the evolutionary time (in yr)

logL

logarithm of the luminosity (L in unit of solar luminosity)

logTe

logarithm of the effective temperature (Te in K)

mass

mass of the star (in unit of solar mass)

Hc

central H/He abundance

logTc

logarithm of the central temperature (Tc in K)

logRHOc

logarithm of the central density (RHOc in g cm^-3)

MHEc

mass of the He core (in unit of solar mass)

Lpp

luminosity of pp chain (in unit of total luminosity L)

LCNO

luminosity of CNO cycle (in unit of total luminosity L)

L3a

luminosity of triple-alpha (in unit of total luminosity L)

Lg

gravitational luminosity (in unit of total luminosity L)

radius

radius of the star (in unit of solar radius)

logg

logarithm of the surface gravity (g in cm s^-2)

Only time, logL, and logTe are mandatory, while all other variables are optional.

hb class contains also the element:

massRGB

the mass of the RGB progenitor

print, and plot methods are available for the two classes.

If baseURL points to an invalid path or CDS ftp site is unavailable the function returns NA and issues a warning.

References

M. Dell'Omodarme, G. Valle, S. Degl'Innocenti, and P.G. Prada Moroni (2012). The Pisa Stellar Evolution Data Base for low-mass stars. Astronomy and Astrophysics, 540, A26.

See Also

getZahb, getHbgrid, getIso, getTrkSet.

Examples

  ## Not run: 
  trk <- getTrk(0.9, 0.002, 0.25, 1.7, 0)

  ### get data from local directory /data
  trk <- getTrk(0.9, 0.002, 0.25, 1.7, 0, baseURL="/data/")

  ###  multi-panel plot of the various quantities with time
  track <- getTrk(0.80, 0.001, 0.25, 1.90, 0)
  if(!is.na(track)[1]) {
  trkdata <- within(stack(track$data), time <- rep(track$data$time,
      length.out=length(values)) )
  require(lattice)
  xyplot( values ~ time | ind, data=trkdata, type="l",
      scales=list(y=list(relation="free")))
  } 
## End(Not run)