News Release Archive:

News Release 10 of 34

September 9, 2009 11:00 AM (EDT)

News Release Number: STScI-2009-25

Hubble Opens New Eyes on the Universe


Image: Probing the Last Gasps of the Doomed Star Eta Carinae

Probing the Last Gasps of the Doomed Star Eta CarinaeSTScI-PRC2009-25i

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The signature balloon-shaped clouds of gas blown from a pair of massive stars called Eta Carinae have tantalized astronomers for decades. Eta Carinae has a volatile temperament, prone to violent outbursts over the past 200 years.

Observations by the newly repaired Space Telescope Imaging Spectrograph (STIS) aboard NASA's Hubble Space Telescope reveal a stream of charged particles from a massive stellar wind and some of the chemical elements that were ejected in the eruption seen in the middle of the nineteenth century.

STIS resolved the chemical information along a narrow section of one of the giant lobes of ejected material. In the resulting spectrum, iron and nickel define the outer material cast off in the nineteenth century from Eta Carinae. STIS also reveals the interior material being carried away by the ongoing wind from Eta Car A, the primary star. The amount of mass being carried away by the wind is the equivalent of one sun every thousand years.

While this "mass loss" may not sound very large, in fact it is an enormous rate among stars of all types. A very faint structure, seen in argon, is evidence of an interaction between winds from Eta Car A and those of Eta Car B, the hotter, less massive, secondary star.

Eta Car A is one of the most massive and most visible stars in the sky. Because of the star's extremely high mass, it is unstable and uses its fuel very quickly, compared to other stars. Such massive stars also have a short lifetime, and astronomers expect that Eta Carinae will explode within a million years.

Eta Carinae was first catalogued by Edmund Halley in 1677. In 1843 Eta Carinae was one of the brightest stars in the sky. It then slowly faded until, in 1868, it became invisible in the sky. Eta Carinae started to brighten again in the 1990s and was again visible to the naked eye. Around 1998 and 1999 its brightness suddenly and unexpectedly doubled.

Eta Carinae is 7,500 light-years away in the constellation Carina.

The Hubble observations are part of the Hubble Servicing Mission 4 Early Release Observations. NASA astronauts repaired STIS during a servicing mission in May to upgrade and repair the 19-year-old Hubble telescope.

Object Name: Eta Carinae

Image Type: Astronomical/Illustration

Credit: NASA, ESA, and the Hubble SM4 ERO Team

Technical facts about this image:

About this Object
Object Name: Eta Carinae (Eta Car)
Object Description: Variable Star
Position (J2000): R.A. 10h 45m 03s.59
Dec. -59° 41' 04".26
Constellation: Carina
Distance: 7,500 light-years (2,300 parsecs)
Dimensions: This image is 0.6 arcminutes (1.2 light-years or 0.4 parsecs) wide.
About these Data
Data Description: The Hubble images were created from data from proposals 11500: K. Noll (STScI) and 11506: K. Noll (STScI), B. Woodgate (NASA/GSFC), C. Proffitt (STScI/CSC), and T. Gull (NASA/GSFC).
Instrument: WFPC2 STIS/CCD
Exposure Date(s): September 5/6, 2008 June 29/30, 2009
Exposure Time: 38 minutes 28 minutes
Filters/Gratings: F336W (U), F502N ([O III]), F631N ([O I]), F656N (H-alpha), and F658N ([N II]) G430M (430nm) and G750M (750nm)
About this Image
Credit: NASA, ESA, and the Hubble SM4 ERO Team
Release Date: September 9, 2009
Color: The image is a composite of separate exposures made by the WFPC2 instrument on the Hubble Space Telescope. Five filters were used to sample narrow wavelength ranges. The color results from assigning different hues (colors) to each monochromatic image. In this case, the assigned colors are:
F658N ([N II]) red
F656N (H-alpha) yellow
F631N ([O I]) green
F502N ([O III]) cyan
F336W (U) blue
Acknowledgments for Eta Car
Observers: K. Noll (STScI), B. Woodgate (NASA/GSFC), C. Proffitt (STScI/CSC), and T. Gull (NASA/GSFC)
Data Analysis: M. Mutchler (STScI)
Image Composition: Z. Levay and L. Frattare (STScI)
Text: D. Weaver and R. Villard (STScI)
Illustrations: Z. Levay (STScI)
Video: G. Bacon (STScI)
Science Consultants: M. Livio (STScI) and T. Gull (NASA/GSFC)


The above montage includes these images:

WFPC2 Image of Eta Carinae Image Type: Astronomical WFPC2 Image of Eta Carinae Eta Car STIS Spectrum Image Type: Astronomical/Data Eta Car STIS Spectrum

All images from this news release:

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