Issue |
A&A
Volume 661, May 2022
|
|
---|---|---|
Article Number | A104 | |
Number of page(s) | 31 | |
Section | Stellar atmospheres | |
DOI | https://doi.org/10.1051/0004-6361/202142957 | |
Published online | 20 May 2022 |
A new and Homogeneous metallicity scale for Galactic classical Cepheids
II. Abundance of iron and α elements★,★★,★★★
1
INAF – Osservatorio Astronomico di Roma,
via Frascati 33,
00078
Monte Porzio Catone,
Italy
2
Agenzia Spaziale Italiana, Space Science Data Center,
via del Politecnico snc,
00133
Rome,
Italy
e-mail: ronaldo.dasilva@ssdc.asi.it
3
Dipartimento di Fisica, Università di Roma Tor Vergata,
via della Ricerca Scientifica 1,
00133
Roma,
Italy
4
INAF – Osservatorio Astronomico di Padova,
Vicolo dell’Osservatorio 5,
35122
Padova, Italy
5
Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg,
Mönchhofstr. 12-14,
69120
Heidelberg, Germany
6
Max Planck Institute for Astronomy,
69117
Heidelberg, Germany; Niels Bohr International Academy, Niels Bohr Institute, Blegdamsvej 17, 2100 Copenhagen, Denmark
7
INAF – Osservatorio Astronomico di Capodimonte,
Napoli, Italy
8
GEPI, Observatoire de Paris, PSL Research University, CNRS,
61 avenue de l’Observatoire,
75014
Paris, France
9
UPJV, Université de Picardie Jules Verne,
33 rue St Leu,
80080
Amiens, France
10
Koninklijke Sterrenwacht van België,
Ringlaan 3,
1180
Brussels, Belgium
11
Science and Technology Department, Parthenope University of Naples,
Naples, Italy
12
Astronomical Observatory, Odessa National University,
Shevchenko Park,
65014
Odessa, Ukraine
13
LMU München, Universitätssternwarte,
Scheinerstr. 1,
81679
München, Germany
14
Institute for Astronomy, University of Hawaii at Manoa,
2680 Woodlawn Drive,
Honolulu,
HI
96822,
USA
15
Department of Astronomy, School of Science, The University of Tokyo,
7-3-1, Hongo, Bunkyo-ku,
Tokyo
113-0033,
Japan
16
Laboratory of Infrared High-Resolution spectroscopy (LiH), Koyama Astronomical Observatory, Kyoto Sangyo University,
Motoyama, Kamigamo, Kita-ku,
Kyoto
603-8555,
Japan
17
Instituto de Astrofísica de Canarias (IAC),
La Laguna
38205,
Spain
18
Departamento de Astrofísica, Universidad de La Laguna (ULL),
38200
La Laguna, Spain
19
INAF-Osservatorio Astronomico d'Abruzzo,
Via M. Maggini, s/n,
64100
Teramo, Italy
20
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati (INFN-LNF),
Frascati, Italy
21
Leibniz-Institut für Astrophysik Potsdam (AIP),
An der Sternwarte 16,
14482
Potsdam, Germany
22
Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS,
Lagrange UMR 7293, CS 34229,
06304
Nice Cedex 4, France
Received:
20
December
2021
Accepted:
13
February
2022
Context. Classical Cepheids are the most popular distance indicators and tracers of young stellar populations. The key advantage is that they are bright and they can be easily identified in Local Group and Local Volume galaxies. Their evolutionary and pulsation properties depend on their chemical abundances.
Aims. The main aim of this investigation is to perform a new and accurate abundance analysis of 20 calibrating Galactic Cepheids. We used high spectral resolution (R ~ 40 000–115 000) and high S/N spectra (~400), covering the entire pulsation cycle.
Methods. We focused our attention on plausible systematics that would affect the estimate of atmospheric parameters and elemental abundances along the pulsation cycle. We cleaned the line list by using atomic transition parameters based on laboratory measurements and by removing lines that are either blended or that display abundance variations along the pulsation cycle.
Results. The spectroscopic approach we developed brings forward small dispersions in the variation of the atmospheric parameters (σ(Teff) ~ 50 K, σ(log g) ~ 0.2 dex, and σ(ξ) ~ 0.2 kms−1) as well as in the abundance of both iron (≲0.05 dex) and α elements (≲0.10 dex) over the entire pulsation cycle. We also provide new and accurate effective temperature templates by splitting the calibrating Cepheids into four different period bins, ranging from short to long periods. For each period bin, we performed an analytical fit with Fourier series providing θ = 5040/Teff as a function of the pulsation phase.
Conclusions. The current findings are a good viaticum for tracing the chemical enrichment of the Galactic thin disk by using classical Cepheids as a fundamental stepping stone for further investigations into the more metal-poor regime that is typical of Magellanic Cepheids.
Key words: Galaxy: disk / stars: abundances / stars: fundamental parameters / stars: variables: Cepheids
Full Tables 2, 3, 4, 8, and 9 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/661/A104
Partly based on observations made with ESO Telescopes at the La Silla/Paranal Observatories under program IDs: 072.D-0419, 073.D-0136, and 190.D-0237 for HARPS spectra; 084.B-0029, 087.A-9013, 074.D-0008, 075.D-0676, and 60.A-9120 for FEROS spectra; 081.D-0928, 082.D-0901, 089.D-0767, and 093.D-0816 for UVES spectra.
© ESO 2022
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