The bright southern Cepheid β Doradus: the radial velocity curve, distance and size

• Published in: Monthly notices of the Royal Astronomical Society Vol. 298; no. 2; pp. 594 - 600
• Main Authors: Taylor, Melinda M., Booth, Andrew J.
• Format: Journal Article
• Language: English
• Published: Oxford, U.K. and Cambridge, USA Blackwell Science Ltd 01.08.1998
• Subjects: Cepheids; stars: atmospheres; stars: fundamental parameters; stars: individual: β Doradus; techniques: radial velocities; techniques: spectroscopic
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1046/j.1365-8711.1998.01670.x

A new high-accuracy velocity curve is presented for the bright southern Cepheid β Doradus (HR 1922), and an investigation into the long-term stability of the velocity curve is made. An upper limit of 0.57 km s−1 is placed on cycle-to-cycle variations. This work is compared with a similar analysis previously applied to the long-period Cepheid l Carinae (HR 3884). Using a near-infrared variant of the Barnes-Evans method, the mean radius of and distance to β Dor are found to be R = 67.8 ± 0.7 R⊙ and d = 349 ± 4 pc. The systematic errors in these parameters are less than 3 per cent. If these systematics can be resolved, through the development of advanced theoretical models and/or the direct measurement of angular diameters, a calibration of the cosmic distance scale to better than 1 per cent can be achieved.