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V440 Per: the longest-period overtone Cepheid

Baranowski, R., Smolec, R., Dimitrov, W., Kwiatkowski, T., Schwarzenberg-Czerny, A., Bartczak, P., Fagas, M., Borczyk, W., Kamiński, K., Moskalik, P., and others. (2009) V440 Per: the longest-period overtone Cepheid. Monthly Notices of the Royal Astronomical Society, 396 (4). pp. 2194-2200. ISSN 0035-8711. (doi:10.1111/j.1365-2966.2009.14865.x)

Abstract

440 Per is a Population I Cepheid with a period of 7.57 d and low-amplitude, almost sinusoidal light and radial velocity curves. With no reliable data on the first harmonic, its pulsation mode identification remained controversial. We obtained a radial velocity curve of V440 Per with our new high-precision and high-throughput Poznań Spectroscopic Telescope. Our data reach an accuracy of 130 m s−1 per individual measurement and yield a secure detection of the first harmonic with an amplitude of A2= 140 ± 15 m s−1. The velocity Fourier phase φ21 of V440 Per is inconsistent at the 7.25σ level with those of fundamental-mode Cepheids, implying that the star must be an overtone Cepheid, as originally proposed by Kienzle et al. Thus, V440 Per becomes the longest-period Cepheid with securely established overtone pulsations. We show that a convective non-linear pulsation hydrocode can reproduce the Fourier parameters of V440 Per very well. The requirement to match the observed properties of V440 Per constrains the free parameters of the dynamical convection model used in the pulsation calculations, in particular the radiative loss parameter.

Item Type: Article
DOI/Identification number: 10.1111/j.1365-2966.2009.14865.x
Additional information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2009 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Uncontrolled keywords: hydrodynamics, methods: data analysis, techniques: spectroscopic, stars: individual: V440 Per, stars: oscillations, Cepheids
Subjects: Q Science > QB Astronomy
Divisions: Faculties > Sciences > School of Physical Sciences > Centre for Astrophysics and Planetary Sciences
Depositing User: Agata Makiela
Date Deposited: 14 Mar 2019 10:20 UTC
Last Modified: 03 Jun 2019 09:33 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/72978 (The current URI for this page, for reference purposes)
Rożek, A.: https://orcid.org/0000-0003-2341-2238
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