NOAO >   Observing Info >   Approved Programs >   2014A-0412

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Proposal Information for 2014A-0412


PI: Armin Rest, Space Telescope Science Institute, arest@stsci.edu
Address: 3700 San Martin Dr., Baltimore, MD 21218, USA

CoI: Federica Bianco, NYU
CoI: Ryan Chornock, Harvard/CfA
CoI: Thomas Matheson, NOAO
CoI: Jose Luis Prieto, Universidad Diego Portales, Chile
CoI: Chris Smith, NOAO
CoI: Nathan Smith, Steward Observatory
CoI: Nolan Walborn, Space Telescope Science Institute
CoI: Doug Welch, McMaster University

Title: Spectrophotometric Time Series of \eta Carinae's Great Eruption

Abstract: \eta Carinae (\eta Car) serves as our most important template for understanding non-SN transients from massive stars in external galaxies. However, until recently, no spectra were available because its historic ``Great Eruption'' (GE) occurred before the invention of the astronomical spectrograph. Now we can also obtain a spectral sequence of the eruption through echoes, which will be of great value since spectra are our most important tool for inferring physical properties of extragalactic transients. \eta Car was seen as the second brightest star in the sky during its 1800s GE, but only visual estimates of its brightness were recorded \citeSF11. In 2011 we discovered several light echoes (LEs) which appear to be from the 1838- 1858 \eta Car eruptions \citeRest12_eta. Subsequent spectroscopic follow-up revealed that its outburst spectral type was most similar to those of G-type supergiants, rather than reported LBV outburst spectral types of F-type (or earlier) \citeRest12_eta. These differences between the GE and the extragalactic transients presumed to be its analogues raise questions about traditional scenarios for the outburst. We propose to obtain a spectrophotometric time series of the GE from \it different directions, allowing the original eruption of \eta Car to be studied as a function of time as well as latitude. A detailed spectroscopic study of the LEs of \eta Car would help us understand (episodic) mass-loss in the most massive evolved stars and their connection to the most energetic core-collapse SNe.


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NOAO >   Observing Info >   Approved Programs >   2014A-0412

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