English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We have measured the brightness variations in Eta Carinae for the past sixyears using the Hubble Space Telescope Space Telescope Imaging Spectrograph andAdvanced Camera for Surveys. Unlike ground-based data, observations by the HSTallow direct measurement of the brightness of the central star by resolving itfrom the surrounding bright ejecta. We find interesting behavior during 2003 inthe continuum and H$\alpha$ emission. The data show that the established longterm brightening trend of Eta Car continues, including regular events whichcoincide with the 5.5 year spectroscopic cycle and other more rapid andunexpected variations. In addition to the HST data, we also presentground-based data obtained from the AAVSO which show many of the same features.The dip in the apparent brightness of the central star at the time of the2003.5 event is wavelength dependent with no decrease in the continuum. Theseobservations cast doubt on asimple eclipse or occultation as the explanationfor the dip and place constraints on the models for the event.Comment: 28 pages, 9 Figures, 3 Tables. Accepted for publication in the AJ  (April 2004

Carinae's Brightness Variations Since 1998:Hubble Space TelescopeObservations of the Central Star