Absolute properties of the pre-main-sequence eclipsing binary star NP Persei

Lacy, Claud H. Sandberg and Fekel, Francis C. and Pavlovski, Krešimir and Torres, Guillermo and Muterspaugh, Matthew W. (2016) Absolute properties of the pre-main-sequence eclipsing binary star NP Persei. Astronomical Journal, 152 (1). Art.No.2. ISSN 0004-6256

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NP Per is a well-detached, 2.2 day eclipsing binary whose components are both pre-main-sequence stars that are still contracting toward the main-sequence phase of evolution. We report extensive photometric and spectroscopic observations with which we have determined their properties accurately. Their surface temperatures are quite different: 6420 ± 90 K for the larger F5 primary star and 4540 ± 160 K for the smaller K5e star. Their masses and radii are 1.3207 ± 0.0087 solar masses and 1.372 ± 0.013 solar radii for the primary, and 1.0456 ± 0.0046 solar masses and 1.229 ± 0.013 solar radii for the secondary. The orbital period is variable over long periods of time. A comparison of the observations with current stellar evolution models from MESA indicates that the stars cannot be fit at a single age: the secondary appears significantly younger than the primary. If the stars are assumed to be coeval and to have the age of the primary (17 Myr), then the secondary is larger and cooler than predicted by current models. The Hα spectral line of the secondary component is completely filled by, presumably, chromospheric emission due to a magnetic activity cycle.

Item Type: Article
Keywords: binary stars ; pre-main-sequence ; stellar evolution
Date: 2016
Subjects: NATURAL SCIENCES > Physics > Astronomy and Astrophysics
Additional Information: © 2016. The American Astronomical Society. Received 2016 February 3. Accepted 2016 March 14. Published 2016 June 6.
Divisions: Faculty of Science > Department of Physics
Project code: IP-2014-09-8656
Publisher: IOP Publishing
Depositing User: Krešimir Pavlovski
Date Deposited: 02 Nov 2017 15:25
Last Modified: 02 Nov 2017 15:25
URI: http://digre.pmf.unizg.hr/id/eprint/5661

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