J/MNRAS/496/5039 Updated PA and PAC relations for Cepheids (De Somma+, 2020)
Updated theoretical period-age and period-age-colour relations for Galactic
Classical Cepheids: an application to the Gaia DR2 sample.
De Somma G., Marconi M., Cassisi S., Ripepi V., Leccia S., Molinaro R.,
Musella I.
<Mon. Not. R. Astron. Soc., 496, 5039-5051 (2020)>
=2020MNRAS.496.5039D 2020MNRAS.496.5039D (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Positional data ; Stars, ages ; Reddening ;
Milky Way ; Optical
Keywords: stars: distances - stars: evolution - stars: oscillations -
stars: variables: Cepheids
Abstract:
Updated evolutionary and pulsational model predictions are combined in
order to interpret the properties of Galactic Classical Cepheids in
the Gaia Data Release 2. In particular, the location of the
instability strip boundaries and the analytical relations connecting
pulsation periods to the intrinsic stellar parameters are combined
with evolutionary tracks to derive reliable and accurate period-age
and the first theoretical period-age-colour relations in the Gaia
bands for a solar chemical abundance pattern (Z=0.02, Y=0.28). The
adopted theoretical framework takes into account possible variations
in the mass-luminosity relation for the core helium-burning stage as
due to changes in the core convective overshooting and/or mass-loss
efficiency, as well as the impact on the instability strip boundaries
due to different assumptions for superadiabatic convection efficiency.
The inferred period-age and period-age-colour relations are applied to
a selected sample of both fundamental and first overtone Gaia
Cepheids, and individual ages for the various adopted theoretical
scenarios are derived. The retrieved age distributions confirm that a
variation in the efficiency of superadiabatic convection in the
pulsational model computations has a negligible effect, whereas a
brighter mass-luminosity relation, as produced by mild overshooting,
rotation, or mass-loss, implies significantly older age predictions.
Moreover, older Cepheids are found at larger Galactocentric distances,
while first overtone Cepheids are found to be systematically older
than the fundamental ones. The comparison with independent age
distribution analysis in literature supports the predictive capability
of current theoretical framework.
Description:
We applied the theoretical period-age (PA) and Gaia-band
period-age-colour (PAC) relations to a sample of Galactic Classical
Cepheids (GCC) published in the Gaia DR2 (Gaia Collaboration
2018A&A...616A...1G 2018A&A...616A...1G, Cat. I/345) and reclassified by Ripepi et al.
(2019A&A...625A..14R 2019A&A...625A..14R, Cat. J/A+A/625/A14).
The selected sample consists of 568 F-mode and 198 FO-mode pulsators.
Using the period and colour values reported by Ripepi et al.
(2019A&A...625A..14R 2019A&A...625A..14R, Cat. J/A+A/625/A14) and the PA and PAC
relations, we derived the individual ages for each adopted assumption
concerning the mass-luminosity (ML) relation.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table6.dat 105 568 Individual ages for the F-mode GCC in our sample
as obtained by using both the canonical PA and
PAC relations
table7.dat 105 568 Individual ages for the F-mode GCC in our sample
as obtained by using both the non-canonical PA
and PAC relations
table8.dat 105 198 Individual ages for the FO-mode GCC in our
sample as obtained by using both the canonical
PA and PAC relations
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/A+A/625/A14 : Reclassification of Cepheids in the Gaia DR2 (Ripepi+, 2019)
Byte-by-byte Description of file: table[678].dat
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Bytes Format Units Label Explanations
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1- 19 I19 --- GaiaDR2 Gaia DR2 source identifier
21- 29 F9.5 deg RAdeg Right ascension (ICRS) at Ep=2015.5
31- 39 F9.5 deg DEdeg Declination (ICRS) at Ep=2015.5
41- 48 F8.5 d P Pulsation period
50- 54 F5.2 mag Gmag Gaia G band magnitude
56- 60 F5.2 mag BPmag Gaia BP band magnitude
62- 66 F5.2 mag RPmag Gaia RP band magnitude
68- 72 F5.2 mag E(BP-RP) Reddening
74- 77 F4.2 mag e_E(BP-RP) Error on E (BP-RP)
79 A1 --- r_E(BP-RP) [LOG] Reference for E (BP-RP) (1)
81- 86 F6.2 Myr tPA Age estimated using the period-age (PA)
relation
88- 92 F5.2 Myr e_tPA Error on tPA
94- 99 F6.2 Myr tPAC Age estimated using the period-age-colour
(PAC) relation
101- 105 F5.2 Myr e_tPAC Error on tPAC
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Note (1): References as follows:
L = Data from literature
O = Reddening was estimated by adopting the PC relation, using (V-I) colour
from the OGLE survey
G = Reddening was estimated by adopting the PC relation, using the
conversion to the Gaia colour
See section 4 of the article for details
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 21-Jul-2023