Astrophysical Quantities of Cepheid Variables Measured with the Navy Prototype Optical Interferometer

By T. Nordgren, J. Armstrong, M. Germain, R. Hindsley, A. Hajian, J. Sudol, Christian A. Hummel. 2000

221 citations recorded by the source corpus.

We present mean angular diameters for two Cepheid variables, α UMi and ζ Gem, determined with the Navy Prototype Optical Interferometer (NPOI). We present linear radii for these Cepheids and two additional Cepheids, δ Cep and η Aql, previously observed at the NPOI. We find the limb-darkened angular diameters of α UMi and of ζ Gem to be 3.28 ± 0.02 and 1.55 ± 0.09 mas, respectively. Using trigonometric parallaxes, we find the linear radii of α UMi, ζ Gem, δ Cep, and η Aql to be 46 ± 3, 60, 45, and 69 R☉, respectively. We compare the pulsation periods and linear radii of this sample of Cepheids, which range in period from 3 to 11 days, to theoretical and empirical period-radius and period-radius-mass relations found in the literature. We find that the observed diameter of α UMi is in excellent agreement with the predicted diameter as determined from both surface brightness techniques and theory only if α UMi is a first-overtone pulsator.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/22b0448f1fc30ec86df9a400ecc9612f99b7346a

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In Astronomy and Astrophysics

1. Pierre Kervella
2. E. D. Folco
3. Damien Ségransan
4. G. Schaefer
5. P. Arriagada
6. T. Barnes
7. H. Bond
8. G. Bono

Citations in the corpus

• Hubble Space Telescope Trigonometric Parallax of Polaris B, Companion of the Nearest Cepheid (2017, methodology): “The angular diameter of Polaris has been measured interferometrically (Nordgren et al. 2000; Mérand et al. 2006).”
• A New Calibration Of Galactic Cepheid Period-Luminosity Relations From B To K Bands, And A Comparison To LMC Relations (2007, methodology): “…observations of a Cepheid were obtained by Mourard et al. (1997), followed by observations from almost all operating interferometers (Lane et al. (2000); Nordgren et al. (2000); Kervella et al. (2001); Kervella et al. (2004c); Mérand et al. (2005); Mérand et al. (2006); Mérand et al. (2007)).”
• DIRECT DETECTION OF THE CLOSE COMPANION OF POLARIS WITH THE HUBBLE SPACE TELESCOPE (2005, methodology): “The pulsation mass of Polaris can also be estimated using the predicted period– mass–radius (PMR) relation for FO Cepheids of Bono et al. (2001a), along with the radius of Polaris, R = 46 ± 3 R , measured interferometrically by Nordgren et al. (2000).”
• The angular sizes of dwarf stars and subgiants Surface brightness relations calibrated by interferometry (2004, background): “The observations of these variable stars by interferometry, intended primarily to study their pulsation, have resulted in the measurement of several of these objects (Mourard et al. 1997; Lane et al. 2000; Nordgren et al. 2000; Kervella et al. 2001; Lane et al. 2002; Kervella et al. 2004b).”