相关论文: Critical Differences and Clues in Eta Car's 2009 E…
Eta Carinae's spectroscopic events (periastron passages) in 2003, 2009, and 2014 differed progressively. He II 4687 and nearby N II multiplet 5 have special significance because they respond to very soft X-rays and the ionizing UV radiation…
The periodic spectroscopic events in eta Carinae are now well established and occur near the periastron passage of two massive stars in a very eccentric orbit. Several mechanisms have been proposed to explain the variations of different…
Aims. Every 5.5 years eta Car's light curve and spectrum change remarkably across all observed wavelength bands. We compare the recent spectroscopic event in mid-2014 to the events in 2003 and 2009 and investigate long-term trends. Methods.…
We describe and analyze Hubble Space Telescope (HST) observations of transient emission near 4680 {\AA} in Eta Car, reported earlier by Steiner & Damineli (2004). If, as seems probable, this is He II $\lambda$4687, then it is a unique clue…
We report on H-alpha spectroscopy of the 2009.0 spectroscopic event of eta Carinae collected via SMARTS observations using the CTIO 1.5 m telescope and echelle spectrograph. Our observations were made almost every night over a two month…
We have observed Eta Carinae over 34 nights between 4th January 2009 and 27th March 2009 covering the estimated timeframe for a predicted spectroscopic event related to a suspected binary system concealed within the homunculus nebula. A…
The periodic events occurring in Eta Carinae have been widely monitored during the last three 5.5-year cycles. The last one recently occurred in January 2009 and more exhaustive observations have been made at different wavelength ranges. If…
In late 2006, ground-based photometry of $\eta$ Car plus the Homunculus showed an unexpected decrease in its integrated apparent brightness, an apparent reversal of its long-term brightening. Subsequent HST/WFPC2 photometry of the central…
Existing HST UV data offer many previously neglected clues to eta Car's behavior since 2000. Here we examine a subset of observations with diverse results. (1) The star's rapid change of state is confirmed by major changes in UV absorption…
We have measured the brightness variations in Eta Carinae for the past six years using the Hubble Space Telescope Space Telescope Imaging Spectrograph and Advanced Camera for Surveys. Unlike ground-based data, observations by the HST allow…
We report on high-resolution spectroscopy of the 2009.0 spectroscopic event of $\eta$ Carinae collected via SMARTS observations using the CTIO 1.5 m telescope and echelle spectrograph. Our observations were made almost every night over a…
The periodicity of 5.5 years for some observational events occurring in Eta Carinae manifests itself across a large wavelength range and has been associated with its binary nature. These events are supposed to occur when the binary…
We present spectroscopic observations with high spectral resolution of eta Car as seen by the SE lobe of the Homunculus nebula over the 2003.5 "spectroscopic event". The observed spectra represent the stellar spectrum emitted near the pole…
We modeled the HeII 4686 line profiles observed in the eta Carinae binary system close to the 2003.5 spectroscopic event, assuming that they were formed in the shocked gas that flows at both sides of the contact surface formed by wind-wind…
Asymmetric variability in ultraviolet images of the Homunculus obtained with the Advanced Camera for Surveys/High Resolution Camera on the Hubble Space Telescope suggests that Eta Carinae is indeed a binary system. Images obtained before,…
During $\eta$ Car's spectroscopic event in mid-2003, the stellar wind's bright H$\alpha$ and H$\beta$ emission lines temporarily had a distinctive shape unlike that reported on any previous occasion, and particularly unlike the 1997--98…
Stellar wind-emission features in the spectrum of eta Carinae have decreased by factors of 1.5-3 relative to the continuum within the last 10 years. We investigate a large data set from several instruments (STIS, GMOS, UVES) obtained…
A full description of the 5.5-yr low excitation events in Eta Carinae is presented. We show that they are not as simple and brief as previously thought, but a combination of two components. The first, the 'slow variation' component, is…
In order to study the distribution of gas and ionizing radiation around eta Car and their implications for its likely companion star, we have examined high-excitation emission lines of [Ne III], [Fe III], etc., in spectra obtained with the…
We analyze spatially resolved spectroscopic observations of the Eta Carinae binary system obtained with HST/STIS. Eta Car is enshrouded by the dusty Homunculus nebula, which scatters light emitted by the central binary and provides a unique…