Eta Carinae

Abstract

A. Damineli, Instituto de Astronomico e Geofisico, Universidade de SaoPaulo, reports that spectroscopic observations collected at the SouthernAstrophysical Research Telescope (La Serena, Chile) by Damineli, J.Steiner, J. H. Groh, and L. Fraga indicate that eta Car reached thephase of minimum excitation on Jan. 11, on schedule with the predictions(Damineli et al. 2008, MNRAS 384, 1649). This supports the 2023-dayperiod and the binary nature of the system. The doubly ionizedforbidden lines and the narrow components of He I and [N II] linesdisappeared from the spectrum. P-Cyg absorption in permittedtransitions (He I, H I, and Fe II) became more enhanced. The He II468.6-nm line, which had been increasing rapidly through 2008 December,has now collapsed abruptly to about 300 milliAngstroems, the same levelas it was a month before. The radial velocity reached -3204 km/s andseems to be still shifting toward the blue. Such results arecorroborated by observations taken at Observatorio do Picos dos Dias(Brazil) by M. Teodoro; at the Complejo Astronomico el Leoncito(Argentina) by E. F. Lajuz, F. Gonzalez, and R. Gamen; at the EuropeanSouthern Observatory 2.2-m telescope by M. Borges Fernandes, C. B.Pereira, C. A. P. C. O. Torres, and M. I. Zevallos Herencia; and at LasCampanas Observatory by N. Morrell. Figures and additional details canbe found at the following website URL: www.etacarinae.iag.usp.br.