Characteristics and interpretation of the photometric variability of eta Carinae and its nebula

• Published in: Space science reviews Vol. 39; no. 3-4; pp. 317 - 373
• Main Authors: VAN GENDEREN, A. M, THE, P. S
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer 01.09.1984
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; Stars; Unusual and peculiar variables; Variable and peculiar stars (including novae); Photometric observation; Mass loss; P Cygni line profile; Variable star; Light curve; Circumstellar shell; Two color diagram; Young star
• ISSN: 0038-6308; 1572-9672
• DOI: 10.1007/BF00173903

The peculiar variable object Eta Car is characterized in a review of observational data (from the 17th century on) and theoretical investigations, with a focus on observations obtained with the Walraven simultaneous VBLUW photometer on the 90-cm light collector, first (1974-1978) at Leiden Southern Station, South Africa, and then (1979-1983) at ESO. The data are presented in tables and graphs and discussed in detail. Findings reported include foreground reddening E(B-V)J = 0.50 mag, homunculus-dust reddening less than 0.6 mag, bolometric magnitude -12.3 + or - 0.2 mag, star radius 96 solar radii (for Teff = 30,000 K), star mass 150 solar mass, mass-loss rate 0.0001 solar mass/yr, and homunculus mass 0.15 solar mass. The 9-mag decrease in light since the maximum in 1843 is attributed to a 2.5-mag decrease in luminosity excess, a 3-mag drop in S Dor effects (probably present since the 17th century), and a 3.5-mag extinction by circumstellar dust, while the recent small-amplitude changes are the result of central-star temperature variations.