NOAO >   Observing Info >   Approved Programs >   2012A-0548

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Proposal Information for 2012A-0548


PI: Federica B. Bianco, LCOGT/UCSB, fbianco@lcogt.net
Address: 6740 Cortona Dr, Goleta, CA 93117, USA

CoI: Armin Rest, Space Telescope Science Institute
CoI: Jose Luis Prieto, Carnegie Observatorie
CoI: Brendan Sinnott, McMaster University
CoI: Nathan Smith, Steward Observatory
CoI: Doug Welch, McMaster University
CoI: D. Andrew Howell, LCOGT/UCSB
CoI: Sean Points, Cerro Tololo Inter-American Observatory

Title: Multiband monitoring of light echoes from the historical eruptions of Eta Carinae

Abstract: \eta Carinae (\eta Car) is one of the most massive binaries in the Milky Way\citeDH97, and its expanding circumstellar nebula has been studied in detail\citeSmith06. It was seen as the second brightest star in the sky during its 1800s ``Great Eruption'', but only visual estimates of its brightness were recorded\citeSF11. In 2011 we discovered several light echoes which appear to be from the 1838-1858 \eta Car eruptions\citeRest11. Our study of their spectra and lightcurves raised questions about traditional scenarios for the outburst and we found important differences between the \eta Car's great eruption and extragalactic transients presumed to be its analogs. However more detailed monitoring of these echoes is necessary. We propose to gather 4 epochs of griz imaging of the \eta Car light echoes. With these data we will be able to (1) ascertain which \eta Car eruption generated each echo, (2) reconstruct the lightcurves of the \eta Car 1838-1858 eruptions to much greater detail than the historical data allowed, (3) reconstruct three-dimensional information about the lightcurves, which can be compared to the well studied shape of the ejecta to constrain symmetry, (4) possibly reveal more ancient, fainter brightenings. Imaging will also facilitate our spectroscopic campaign of \eta Car's echoes. With these lightcurves and spectra we will investigate explosion mechanisms for the \eta Car eruptions that still elude us.


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