Open AccessOn the pulsation parallax of the variable star RR Lyr
Author(s) -
Bono G.,
Caputo F.,
Castellani V.,
Marconi M.,
Storm J.
Publication year - 2002
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2002.05573.x
Subject(s) - rr lyrae variable , physics , astrophysics , parallax , globular cluster , extinction (optical mineralogy) , horizontal branch , variable star , luminosity , stars , rosat , absolute magnitude , cepheid variable , astronomy , galaxy , optics
We show that a straightforward application of the predicted relation connecting the absolute K magnitude of fundamental RR Lyrae variables to their period and metal content, together with current evolutionary predictions on the mass and luminosity of Horizontal Branch stars, supply a distance estimate to the prototype star RR Lyr in close agreement with the recent parallax determination by the Hubble Space Telescope ( HST ; Benedict et al.), largely unaffected by the interstellar extinction correction. Adopting 〈 A V 〉=0.12±0.10 mag as a safe estimate of the extinction correction to RR Lyr, we obtain a ‘pulsation’ parallax π puls =3.858±0.131 mas which agrees quite well, and with a smaller formal error, with the HST measurement (π abs =3.82±0.20 mas) and with the weighted average of HST , Hipparcos , and ground‐based determinations (〈π abs 〉=3.87±0.19 mas) . This result suggests that near‐infrared magnitudes and pulsation models could constrain the distance to well‐studied RR Lyrae stars, both in the field and in globular clusters, with an accuracy better than current direct trigonometric measurements.