A&A 546, A105 (2012) Astronomy DOI: 10.1051/0004-6361/201117166 & c ESO 2012 Astrophysics The hypergiant HR 8752 evolving through the yellow evolutionary void, H. Nieuwenhuijzen1 , C. De Jager1,2, I. Kolka3, G. Israelian4, A. Lobel5, E. Zsoldos6, A. Maeder7, and G. Meynet7 1 SRON Laboratory for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands e-mail:
[email protected];
[email protected] 2 NIOZ, Royal Netherlands Institute for Sea Research, PO Box 59, Den Burg, The Netherlands e-mail:
[email protected] 3 Tartu Observatory, 61602 Tõravere, Estonia e-mail:
[email protected] 4 Instituto de Astrofisica de Canarias, via Lactea s/n, 38200 La Laguna, Tenerife, Spain e-mail:
[email protected] 5 Royal Observatory of Belgium, Ringlaan 3, 1180 Brussels, Belgium e-mail:
[email protected];
[email protected] 6 Konkoly Observatory, PO Box 67, 1525 Budapest, Hungary e-mail:
[email protected] 7 Observatoire de Genève, 1290 Sauverny, Switzerland e-mail: [Andre.Maeder;Georges.Meynet]@unige.ch Received 30 April 2011 / Accepted 13 March 2012 ABSTRACT Context. We study the time history of the yellow hypergiant HR 8752 based on high-resolution spectra (1973–2005), the observed MK spectral classification data, B − V-andV-observations (1918–1996) and yet earlier V-observations (1840–1918). Aims. Our local thermal equilibrium analysis of the spectra yields accurate values of the effective temperature (Teff ), the accelera- tion of gravity (g), and the turbulent velocity (vt) for 26 spectra. The standard deviations average are 82 K for Teff,0.23forlogg, −1 and 1.1 km s for vt.