The MAGIC project – II. Discovery of two new Galactic lithium-rich Cepheids-Reference-Cited by-同舟云学术

The MAGIC project – II. Discovery of two new Galactic lithium-rich Cepheids

Published:2019-07-22 Issue:3 Volume:488 Page:3211-3221
ISSN:0035-8711
Container-title:Monthly Notices of the Royal Astronomical Society
language:en
Short-container-title:

Author:

Kovtyukh V¹²,Lemasle B³,Kniazev A⁴⁵⁶^ORCID,Berdnikov L⁶,Bono G⁷⁸,Usenko I¹²⁹,Grebel E K³,Hajdu G³¹⁰¹¹,Pastukhova E¹²

Affiliation:

1. Astronomical Observatory, Odessa National University, Shevchenko Park, UA-65014, Odessa, Ukraine

2. Isaac Newton Institute of Chile, Odessa branch, Shevchenko Park, UA-65014, Odessa, Ukraine

3. Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstr. 12-14, D-69120 Heidelberg, Germany

4. South African Astronomical Observatory, PO Box 9, 7935 Observatory, Cape Town, South Africa

5. Southern African Large Telescope Foundation, PO Box 9, 7935 Observatory, Cape Town, South Africa

6. Sternberg Astronomical Institute, Lomonosov Moscow State University, Universitetskij Pr. 13, Moscow 119992, Russia

7. Dipartimento di Fisica, Universitá di Roma Tor Vergata, via della Ricerca Scientifica 1, I-00133 Rome, Italy

8. INAF – Osservatorio Astronomico di Roma, via Frascati 33, Monte Porzio Catone, Rome, Italy

9. Mykolaiv Astronomical Observatory, Obsevatorna 1, Mykolaiv UA-54030, Ukraine

10. Instituto de Astrofisica, Pontificia Universidad Catolica de Chile, Av. Vicuña Mackenna 4860, 782-0436 Macul, Santiago, Chile

11. Instituto Milenio de Astrofisica, Santiago, Chile

12. Institute of Astronomy, Russian Academy of Sciences, ul. Pyatnitskaya 48, Moscow 119017, Russia

Abstract

Abstract We report the discovery of two new lithium-rich Cepheids in the Milky Way (A(Li) ≈ 2.9 dex) among the targets of the MAGIC spectroscopic survey with the Southern African Large Telescope spectrographs. The 6707 Å Li feature is usually not detectable in the atmosphere of Cepheids. Only three Cepheids (two in the Milky Way and one in the Large Magellanic Cloud) had been reported so far with high lithium abundances. We examine the possibility that the Li-rich Cepheids are evolving towards the red giant branch, crossing the instability strip for the first time, as well as other possible scenarios. The two stars are mixed-mode Cepheids pulsating simultaneously in the first and in the second overtone modes. We briefly discuss the possible connection between their unusual chemical composition and their pulsational properties.

Funder

German Research Foundation

Fondo Nacional de Desarrollo Científico y Tecnológico

Consejo Nacional de Innovación, Ciencia y Tecnología

Deutscher Akademischer Austauschdienst

National Research Foundation

Russian Science Foundation

Publisher

Oxford University Press (OUP)

Subject

Space and Planetary Science,Astronomy and Astrophysics

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