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OGLE-GAL-ACEP-091: The First Known Multi-mode Anomalous Cepheid

Soszyński, I. and Smolec, R. and Udalski, A. and Szymanski, M. K. and Pietrukowicz, P. and Skowron, D. M. and Skowron, J. and Mróz, P. and Poleski, R. and Kozłowski, S. and Iwanek, P. and Wrona, M. and Gromadzki, M. and Ulaczyk, K. and Rybicki, K. (2020) OGLE-GAL-ACEP-091: The First Known Multi-mode Anomalous Cepheid. Astrophysical Journal Letters, 901 (2). Art. No. L25. ISSN 2041-8213.

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Anomalous Cepheids (ACs) are metal-deficient, core-helium-burning pulsating stars with masses in the range 1.2–2.2 M_⊙. Until recently, all known ACs were pure single-mode pulsators. The first candidate for an AC pulsating in more than one radial mode—OGLE-GAL-ACEP-091—was recently identified in the Milky Way based on the photometric database of the Optical Gravitational Lensing Experiment (OGLE) survey. We analyze this object showing that it is actually a triple-mode pulsator. Its position in the Petersen diagram, the light-curve morphology quantified by Fourier coefficients, and absolute magnitudes derived from the Gaia parallax are consistent with the assumption that OGLE-GAL-ACEP-091 is an AC. Our grid of linear pulsation models indicates that OGLE-GAL-ACEP-091 is a 1.8 M_⊙ star with a metallicity of about [Fe/H] = −0.5 dex.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Soszyński, I.0000-0002-7777-0842
Smolec, R.0000-0001-7217-4884
Udalski, A.0000-0001-5207-5619
Szymanski, M. K.0000-0002-0548-8995
Pietrukowicz, P.0000-0002-2339-5899
Skowron, D. M.0000-0001-9439-604X
Skowron, J.0000-0002-2335-1730
Mróz, P.0000-0001-7016-1692
Poleski, R.0000-0002-9245-6368
Kozłowski, S.0000-0003-4084-880X
Iwanek, P.0000-0002-6212-7221
Wrona, M.0000-0002-3051-274X
Gromadzki, M.0000-0002-1650-1518
Ulaczyk, K.0000-0001-6364-408X
Rybicki, K.0000-0002-9326-9329
Additional Information:© 2020. The American Astronomical Society. Received 2020 August 19; revised 2020 September 7; accepted 2020 September 13; published 2020 September 25. We thank Dr. Giuseppe Bono, the referee of this Letter, for his valuable comments on this work. This work has been supported by the National Science Centre, Poland, grant MAESTRO No. 2016/22/A/ST9/00009. The OGLE project has received funding from the Polish National Science Centre grant MAESTRO No. 2014/14/A/ST9/00121. R.S. was supported by the National Science Center, Poland, Sonata BIS project 2018/30/E/ST9/00598. This work is based in part on observations made with the Spitzer Space Telescope, which was operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA.
Funding AgencyGrant Number
National Science Centre (Poland)2016/22/A/ST9/00009
National Science Centre (Poland)2014/14/A/ST9/00121
Sonata-bis Program2018/30/E/ST9/00598
Subject Keywords:Anomalous Cepheid variable stars ; Multi-periodic pulsation ; Pulsating variable stars
Issue or Number:2
Classification Code:Unified Astronomy Thesaurus concepts: Anomalous Cepheid variable stars (2106); Multi-periodic pulsation (1078); Pulsating variable stars (1307)
Record Number:CaltechAUTHORS:20200925-091914617
Persistent URL:
Official Citation:I. Soszyński et al 2020 ApJL 901 L25
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105541
Deposited By: George Porter
Deposited On:25 Sep 2020 17:40
Last Modified:25 Sep 2020 17:40

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