CMD 3.7 input form

A web interface dealing with stellar isochrones and their derivatives

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Evolutionary tracksPARSEC tracks (Bressan et al. (2012)) are computed for a scaled-solar composition and following the Y=0.2485+1.78Z relation. The present solar metal content is Z☉=0.0152. Tables of evolutionary tracks are also available. COLIBRI tracks (Marigo et al. (2013)) extend their evolution to the end of the TP-AGB phase, for several choices of mass loss and dredge up parameters.
Available sets of tracks:
going from the PMS to either the 1st TP, or C-ignition: add the TP-AGB evolution, from the 1st TP to the total loss of envelope:
PARSEC version 2.0
Available for 0.004≤Z≤0.017 (-0.58≤[M/H]≤+0.07), with rotation turned off for lower masses, cf. Nguyen et al. (2022).
Notes: this choice will (1) turn off features like the star-by-star extinction, the Reimers-resettable mass loss, etc. and (2) change the output format.
PARSEC version 1.2S
Available for 0.0001≤Z≤0.06 (-2.2≤[M/H]≤+0.5); for 0.0001≤Z≤0.02 the mass range is 0.1≤M/M☉<350; for 0.03≤Z≤0.04 0.1≤M/M☉<150, and for Z=0.06 0.1≤M/M☉<20 (cf. Tang et al. (2014) for 0.001≤Z≤0.004, and Chen et al. (2015) for other Z). With revised and calibrated surface boundary conditions in low-mass dwarfs (Chen et al. (2014)).
+ COLIBRI S_37 (Pastorelli et al. (2020)) for 0.008≤Z≤0.02, + COLIBRI S_35 (Pastorelli et al. (2019)) for 0.0005≤Z≤0.006 + COLIBRI PR16 (Marigo et al. (2013), Rosenfield et al. (2016)) for Z≤0.0002 and Z≥0.03 )
+ COLIBRI S_35 (Pastorelli et al. (2019)) (limited to 0.0005≤Z≤0.03)
+ COLIBRI S_07 (Pastorelli et al. (2019)) (limited to 0.0005≤Z≤0.03)
+ COLIBRI PR16 (Marigo et al. (2013) and Rosenfield et al. (2016)) (limited to 0.0001≤Z≤0.06)
No (no limitation in Z)
PARSEC version 1.1
Available for 0.0001≤Z≤0.06 (-2.2≤[M/H]≤+0.5), in the range 0.1≤M/M☉<12. With revised diffusion+overshooting in low-mass stars, and improvements in interpolation scheme.
PARSEC version 1.0
Available for 0.0005≤Z≤0.07 (-1.5≤[M/H]≤+0.6), in the range 0.1≤M/M☉<12.
Add post-AGB and WD evolution? Not yet (it's in preparation)
You can also specify:
  • the resolution of the thermal pulse cycles in the COLIBRI section: ninTPC= as detailed in Marigo et al. (2017)
  • mass-loss on the RGB using the Reimers formula with ηReimers=

Warning: mass loss works fine as long as ηReimers<0.5. Check the results for higher values.

Previous sets of tracks, described on Girardi et al. (2010), Marigo et al. (2008), Girardi et al. (2000), and Bertelli et al. (1994), are no longer included in the CMD web interface v3.2+. They can be retrieved with previous versions (for instance, try CMD v3.1)
Photometric system

Choose among the available photometric systems: They are briefly described here.

Available sets of bolometric corrections:
version short description
spectral libraries
for "normal stars" for cool giants for very hot stars and WRs
YBC The revised and expanded library described in Chen et al. (2019). See also the YBC web interface, which provides more options with the stellar spectral libraries (eg., Kurucz only or Phoenix only). An mix of ATLAS9 ODFNEW (Castelli & Kurucz (2004)) and PHOENIX BT-Settl (Allard et al. (2012)) O-rich and C-rich spectra from COMARCS, Aringer et al. (2009) and Aringer et al. (2016) from Chen et al. (2015), O, B star models computed with WM-basic, WR star models from PoWR
YBC +new Vega As above, but adopting revised SED for Vega from Bohlin et al. (2020) (namely CALSPEC alpha_lyr_stis_010.fits).
OBC The library used in most Padova+PARSEC isochrones, described in Girardi et al. (2002) and then expanded until Marigo et al. (2017) Mostly based on ATLAS9 ODFNEW from Castelli & Kurucz (2004), as described on Girardi et al. (2008) O-rich and C-rich spectra from COMARCS, Aringer et al. (2009) and Aringer et al. (2016) blackbodies...
Circumstellar dustThis will only affect stars in the TP-AGB phase and with significant mass loss. In the case of Bressan et al. (1998) and Groenewegen (2006), the RT calculations are applied using the scaling relations described in Marigo et al. (2008) (see alsp Pastorelli et al. (2019)). In the case of Nanni et al. (2016), the dust growth model is fixed for M stars, while one can choose between a few sets of optical data for C stars.
Available dust compositions:
for M stars for C stars

Using scaling relations
as in Marigo et al. (2008):
No dust No dust
Silicates as in Bressan et al. (1998) Graphites as in Bressan et al. (1998)
100% AlOx as in Groenewegen (2006) 100% AMC as in Groenewegen (2006)
60% Silicate + 40% AlOx as in Groenewegen (2006) 85% AMC + 15% SiC as in Groenewegen (2006)
100% Silicate as in Groenewegen (2006)

Other options for C-star dust were discarded starting from CMD v3.7.
Interstellar extinctionTotal extinction AV = mag.
Apply this extinction
Using extinction coefficients computed star-by-star (except for the OBC case, which uses constant coefficients)
Adopted extinction curve
Cardelli et al. (1989) + O'Donnell (1994), with RV=3.1

Warning: Interstellar extinction works only for isochrone tables, not for LFs or simulated populations. Moreover, it does not work (yet) on the PARSEC rotating models.

Long Period VariabilityWe provide three options to simulate long-period variability during the RGB and AGB phase. All three provide the periods for a set of pulsation modes as well as the quantity pmode, whose integer value indicates the radial order of the dominant pulsation mode: 0 is the fundamental mode (FM), 1 the first overtone mode (1OM), and so on. The value -1 indicates that no mode is expected to be excited, or that the stellar parameters are outside the range of validity for computing variability properties.
Prescription Description
1. Periods from Trabucchi et al. (2017).
FM and 1OM periods from preliminary best-fit relations. These are provided for backwards compatibility and are superseded by the option 2 below.
2. Periods from Trabucchi et al. (2019).
Periods for the FM, 1OM, 2OM, 3OM, and 4OM. They are derived from best-fit relations based on linear pulsation models, so this is the most appropriate option for who is interested in studying overtone mode pulsation, but is not appropriate for the FM. Note: as an alternative, you can use Trabucchi's pulsation code, which will include the growth rates.
3. Periods from Trabucchi et al. (2021).
Same as the option 2 except that the FM period and the regime in which it is dominant (i.e. when pmode=0) are determined from non-linear pulsation models. This option is the most appropriate for studying the FM.
Cautionary remarks When options 2 or 3 are used, most stars with small luminosity/mass ratio are assigned a value pmode=4. This does not necessarily mean that the 4th overtone is really dominant. Indeed, there seems to be no clear observational detection of the 4th overtone mode in AGB stars, suggesting that it either is stable or has very small amplitude (see Trabucchi et al. (2017)). Therefore it is reasonable to interpret the occurrences of pmode=4 as an indication that the star displays only small-amplitude oscillations, if any. The origin of this patter is the following. The prescription from Trabucchi et al. (2019) used to assign the value of pmode exploits the fact that the dominant mode shifts towards pulsation modes of increasingly smaller radial order as the stellar luminosity increase. This is achieved by comparing the actual luminosity of a simulated star with the value of luminosity corresponding to the transition between two pulsation modes. Since the pulsation models of Trabucchi et al. (2019) do not include properties of pulsation modes higher than the 4th overtone, there is no prediction for the lower luminosity boundary of the regime in which it is dominant.
Initial mass functionThe IMF will be used to compute the stellar occupation along the isochrones, and to compute integrated magnitudes, LFs, etc. (see section Output below)
IMF for single stars:

Ages/metallicitiesChoose your metallicity values using the approximation [M/H]=log(Z/X)-log(Z/X)☉, with (Z/X)=0.0207 and Y=0.2485+1.78Z for PARSEC tracks.

Input form for multiple values of ages/metallicities (up to a maximum of 1e4 isochrones):
initial value final value step (use 0 for a single value)
linear age (yr) = yr yr yr
log(age/yr) = dex dex dex
metal fraction Z =
[M/H] = dex dex dex

OutputKind of output:
Isochrone tables: stellar parameters as a function of initial mass
Luminosity functions: star counts expected, in the interval from to mag, with bins mag wide, per 1 Msun of stellar population
Simulated populations with a total mass of Msun
Single-burst stellar populations, integrated magnitudes (for 1 Msun)

gzip the output file (Files above 50 Mby will always be gzipped!)

This service is mantained by Léo Girardi at the Osservatorio Astronomico di Padova.
Questions, comments and special requests should be directed to leo.girardi@oapd·inaf·it .
Last modified: Tue Jul 19 09:07:17 2022