Name: Mairan Teodoro

Institution: IAG/USP

e-mail: mairan(no-spam)astro.iag.usp.br

Partner Contry: BRA

Science Meeting: Yes

User Meeting: None Selected

NGO Staff Meeting: None Selected

Presentation: Yes

Format: Poster

Title: A near-infrared view of the Homunculus nebula with Gemini/CIRPASS

Co-author: Augusto Damineli Robert Sharp Jose Henrique Groh Cassio Leandro Barbosa

Co-authors' Institutions: IAG/USP Anglo-Australian Observatory IAG/USP IP&D-Univap

Abstract:

We present integral field spectroscopy of the Homunculus nebula around eta Carinae in the near-infrared window, encompassing spectral lines sensitive to shocks and photo-ionisation. We use the [Fe II] 12567/Pa-gamma ratio to trace the regions excited by collisions and the He I 10830 line to map photo-excitation. We report the detection of a hole in both lobes near the pole and use a cylindrical model to match the observations and then determine the thickness of the lobes at the polar region and the radius of the holes. We map the blue-shifted beamed component seen in the He I 10830 as an intrinsic emission in front of the NW lobe and conclude that it is formed by the UV photoexcitation escaping directly from the Purple Haze as it extends to outside the limits of the lobes and do not seems to lay on the equatorial disc. Our velocity maps reveal that the spatial distribution of the Little Homunculus is coincident with the radio continuum emission at 3 cm, indicating that it is a photon-bounded H II region. We also use the 1.3-mm radio flux to constrain the luminosity of the secondary star in the system showing that a lower limit for the luminosity corresponds to an O7I or WNha star.