Astrometry with the Hubble Space Telescope: A Parallax of the Fundamental Distance Calibrator δ Cephei

By G. Benedict, B. Mcarthur, L. Fredrick, T. Harrison, Catherine Slesnick, J. Rhee, R. Patterson, M. Skrutskie, O. Franz, L. Wasserman and 9 more. 2002

287 citations recorded by the source corpus.

We present an absolute parallax and relative proper motion for the fundamental distance scale calibrator δ Cep. We obtain these with astrometric data from FGS 3, a white-light interferometer on the Hubble Space Telescope (HST). Utilizing spectrophotometric estimates of the absolute parallaxes of our astrometric reference stars and constraining δ Cep and reference star HD 213307 to belong to the same association (Cep OB6), we find πabs = 3.66 ± 0.15 mas. The larger than typical astrometric residuals for the nearby astrometric reference star HD 213307 are found to satisfy Keplerian motion with P = 1.07 ± 0.02 yr, a perturbation and period that could be due to an F0 V companion ∼7 mas distant from and ∼4 mag fainter than the primary. Spectral classifications and VRIJHKT2M and DDO51 photometry of the astrometric reference frame surrounding δ Cep indicate that field extinction is high and variable along this line of sight. However the extinction suffered by the reference star nearest (in angular separation and distance) to δ Cep, HD 213307, is lower and nearly the same as for δ Cep. Correcting for color differences, we find ⟨AV⟩ = 0.23 ± 0.03 for δ Cep and hence an absolute magnitude MV = -3.47 ± 0.10. Adopting an average V magnitude, ⟨V⟩ = 15.03 ± 0.03, for Cepheids with log P = 0.73 in the large Magellanic Cloud (LMC) from Udalski et al., we find a V-band distance modulus for the LMC, m - M = 18.50 ± 0.13, or 18.58 ± 0.15, where the latter value results from a highly uncertain metallicity correction. These agree with our previous RR Lyr HST parallax-based determination of the distance modulus of the LMC.

Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/4e98ed965ae71956e5b000e5acb0870c496d8493

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In Astronomy and Astrophysics

1. M. Feast
2. P. Whitelock
3. G. Schaefer
4. F. V. Leeuwen
5. H. Bond
6. E. Nelan
7. H. Mcalister
8. N. Evans

In Atomic and Molecular Physics, and Optics

1. J. Bean
2. G. Bono
3. Richard de Grijs
4. Pierre Kervella

Citations in the corpus

• Hubble Space Telescope Fine Guidance Sensor Parallaxes of Galactic Cepheid Variable Stars: Period-Luminosity Relations (2006, methodology): “Hence, we use the modeling approach outlined in Benedict et al. (2002b), with corrections for both cross-filter and lateral color positional shifts, using values specific to FGS 1r determined from previous calibration observations with that FGS.”
• Multiplicity of Galactic Cepheids from long-baseline interferometry – III. Sub-percent limits on the relative brightness of a close companion of δ Cephei (2016, methodology): “…with several observing techniques and wavelengths, revealing little by little new unseen physical properties. δ Cep is known to have an A0-type visual companion located at about 40′′(Fernie 1966; Prugniel et al. 2007), which turns out to have itself an astrometric component (Benedict et al. 2002).”
• Cepheid parallaxes and the Hubble constant (2007, methodology): “…of 10 Cepheids, measured with the Hubble Space Telescope (HST) and corrected to an absolute reference frame using ground-based observations, have been published and discussed (Benedict et al. 2002, Benedict et al. 2007 henceforth FB2007) and we have incorporated these data in our analysis.”
• CLUSTERING OF LOCAL GROUP DISTANCES: PUBLICATION BIAS OR CORRELATED MEASUREMENTS? III. THE SMALL MAGELLANIC CLOUD (2014, background): “Hubble Space Telescope-based parallaxes are less seriously affected by these parallax errors (e.g., Benedict et al. 2002, 2007) than the earlier Hipparcos measurements, although the revised Hipparcos parallaxes (van Leeuwen 2007) provide a significantly improved calibration data set.9 In the…”
• A New Calibration Of Galactic Cepheid Period-Luminosity Relations From B To K Bands, And A Comparison To LMC Relations (2007, methodology): “We use two sources of trigonometric parallaxes: HST parallaxes, published by Benedict et al. (2002) and Benedict et al. (2007), and the revised Hipparcos parallaxes of Cepheids, from van Leeuwen et al. (2007).”
• Hubble Space Telescope Trigonometric Parallax of Polaris B, Companion of the Nearest Cepheid (2017, result): “Hipparcos parallaxes have usually agreed with the results of HST/FGS measurements, or of other parallax techniques, to within their respective errors (e.g., Benedict et al. 2002; McArthur et al. 2011; Bond et al. 2013).”