THE PULSATION MODE AND DISTANCE OF THE CEPHEID FF AQUILAE
- Department of Astronomy and Physics, Saint Mary's University, Halifax, NS B3H 3C3 (Canada)
- Astronomical Observatory, Odessa National University, and Isaac Newton Institute of Chile, Odessa Branch, T. G. Shevkenko Park, 65014 Odessa (Ukraine)
- Department of Astronomy, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106-7215 (United States)
The determination of pulsation mode and distance for field Cepheids is a complicated problem best resolved by a luminosity estimate. For illustration a technique based on spectroscopic luminosity discrimination is applied to the 4.47 day s-Cepheid FF Aql. Line ratios in high dispersion spectra of the variable yield values of (M{sub V} ) = -3.40 {+-} 0.02 s.e. ({+-}0.04 s.d.), average effective temperature T{sub eff} = 6195 {+-} 24 K, and intrinsic color ((B) - (V)){sub 0} = +0.506 {+-} 0.007, corresponding to a reddening of E{sub B-V} = 0.25 {+-} 0.01, or E{sub B-V}(B0) = 0.26 {+-} 0.01. The skewed light curve, intrinsic color, and luminosity of FF Aql are consistent with fundamental mode pulsation for a small-amplitude classical Cepheid on the blue side of the instability strip, not a sinusoidal pulsator. A distance of 413 {+-} 14 pc is estimated from the Cepheid's angular diameter in conjunction with a mean radius of (R) = 39.0 {+-} 0.7 R{sub Sun} inferred from its luminosity and effective temperature. The dust extinction toward FF Aql is described by a ratio of total-to-selective extinction of R{sub V} = A{sub V} /E(B - V) = 3.16 {+-} 0.34 according to the star's apparent distance modulus.
- OSTI ID:
- 22140338
- Journal Information:
- Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 1 Vol. 772; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
Similar Records
A SEARCH FOR OB ASSOCIATIONS NEAR SOUTHERN LONG-PERIOD CEPHEIDS. V. AQ PUPPIS AND V620 PUPPIS
Cepheid companions FM Aquilae, FN Aquilae, RX Aurigae, Y Lacertae, and RS Orionis