Memo on the Horizontal Branch Models -
(data)
MEMO ON THE ISOCHRONES
Here we make available all the turnoff
isochrones computed and described in the paper by D'Antona, Mazzitelli and Caloi (1997,
ApJ, 10 March issue) ( see also the + figures file ), plus some
isochrones relative to the computations in
Mazzitelli, D'Antona and Caloi 1995
(A&A 302, 382). In addition, the horizontal branch
tracks of Caloi, D'Antona
and Mazzitelli (1997, A&A, in press) are also available.
The file "turnoff.data" gives the turnoff values for the different
sets of models and ages.
The files are named as follows:
- Letter 1-2: "fs" or "ml" indicates the convection model adopted in the
model computations: "fs": Full Spectrum Turbulence model (either from Canuto
and Mazzitelli, 1991; or from Canuto, Goldman and Mazzitelli 1996); "ml":
Mixing Length Theory treatment (from Cox and Giuli); l/H_p=1.5 is adopted in
all models;
- Letters 3-4: refer to the metallicity of the isochrone (Z, in mass
fraction); also the helium mass fraction Y is listed below:
- 14: Z=10^{-4} Y=0.23
- 24: Z=2 10^{-4} Y=0.23
- 34: Z=3 10^{-4} Y=0.23
- 64: Z=6 10^{-4} Y=0.23
- 13: Z=10^{-3} Y=0.235
- 23: Z=2 10^{-3} Y=0.235
- 43: Z=4 10^{-3} Y=0.235
- Letters 5,6,7,8: "st95" indicates models from Mazzitelli et al. 1995;
"st96" refers to mdoels from D'Antona et al. 1997. The main difference is in
the e.o.s. adopted, the most recent models include the Rogers et al. e.o.s..
The 95 models adopt the Daeppen et al. 1988 e.o.s.. Standard models include
no sedimentation and, for the FS models, the Canuto and Mazzitelli 1991
convection treatment, with beta=0.178. The M_v, B-V values are obtained by
Kurucz (1993) transformations. BC(Sun) for Kurucz's grid is -0.19. We take
as observed value for M_v(Sun)=4.79, so that M_bol(Sun)=4.59. Should one
prefer M_v(Sun)=4.82, just add 0.03 mag to the listed values of M_v. We are
responsible for the logL - logTeff values given in the isochrones, but urge
the interested researchers to check the Mv - B-V values by other sets of
model atmospheres or semiempirical calibration, as the field is very fluid.
Some models are labelled "vd" in place of "st": in these, the Vandenberg
1992 color transformations are adopted.
Non standard models:
For the metallicity Z=2 10^{-4}, we also give non standard isochrones,
labelled by "n" (new) at the third letter. These include the new fluxes by
Canuto, Goldman and Mazzitelli 1996 in place of the plain Canuto and
Mazzitelli 1991 fluxes, and Alexander and Ferguson (1994) low temperature
opacities in place of Kurucz (1993).
- "n01n" : in these isochrones the parameter beta ("overshooting")
is =0.1, and no sedimentation is considered;
- "n01s": the same, but including also helium sedimentation;
- "n02s": the same, but with beta=0.2 and helium sedimentation.
Extension: indicates the age in gigayears (from 10 to 20).
FILES CONTENT:
- column 1: mass in solar units
- column 2: logL/Lsun
- column 3: log Teff
- column 4: Mbol (in Kurucz 1993 system, for which we set Mbol(Sun) is 4.59)
- column 5: Mv
- column 6: B-V
MEMO ON THE HORIZONTAL BRANCH TRACKS
Here are available all the turnoff isochrones computed for the
paper by Caloi, D'Antona
and Mazzitelli (1997, A&A, in press) The
description of model inputs is also in Mazzitelli, D'Antona and Caloi 1995,
A&A 302, 382. The files are ordered as follows:
- The first line contains specification of mass (solar units), log metals mass
fraction, initial helium content and helium core mass.
- Letter 1,2,3: vhb: indicates we are in the presence of tracks for Horizontal
Branch evolution;
- letters 4.5 refer to the metallicity (m4=10^-4 and so on).
extension: gives the mass of the track, in solar units.
The files contain:
- column 1: age, counted from the homogeneus starting model. Ages begin from
- column 2: logL/Lsun
- column 3: log Teff
- column 4: Mbol (in Kurucz 1993 system: Mbol(Sun) is 4.59)
- column 5: Mv
- column 6: B-V
Unless differently specified, Kurucz (1993) correlations Teff -- B-V -- BC
have been used.
We are responsible for the logL - logTeff values given in the isochrones, but
urge the interested researchers to check the Mv - B-V values by other sets of
model atmospheres or semiempirical calibration, as the field is very fluid.
Copyright © 1995, Osservatorio Astronomico di Roma
Comments on this screen to
buscema@www.mporzio.astro.it
