Eta Carinae is RED ???

[skysurfer]

I am talking about the star, not the nebula.
Using my binos or telescope Eta appears red to me like Antares or Betelgeuse ?
Is it an M type giant ?
The largest online astronomy textbook says the spectral type is Variable / O and a surface temperature of 9300 K or hotter.
How can it be red ?

[xelasnave]

Dust?
Alex

[astroron (Ron)]

Originally Posted by skysurfer

I am talking about the star, not the nebula.
Using my binos or telescope Eta appears red to me like Antares or Betelgeuse ?
Is it an M type giant ?
The largest online astronomy textbook says the spectral type is Variable / O and a surface temperature of 9300 K or hotter.
How can it be red ?

Were are you observing it from?
I see you're in Bellengin NSW
Depending what time you observed it ,you could be observing it low down
so the colour could be of a reddish ewe.
It comes across to me as a bright white to yellow.

[skysurfer]

Originally Posted by astroron

Were are you observing it from?
I see you're in Bellengin NSW
Depending what time you observed it ,you could be observing it low down
so the colour could be of a reddish ewe.
It comes across to me as a bright white to yellow.

It is just at 21:00 hours when Eta is high in the sky. And the sky is crystal clear, i.e. no haze. Other O/B/A/F class stars (including stars lower in the sky, such as Acrux) look bluish white as expected.

It may be the star itself is embedded in dust (Homunuculus nebula) which makes the color reddish ?

[Shiraz (Ray)]

http://www.iceinspace.com.au/forum/s...d.php?t=173114

Gary's very interesting post might be useful - seems there is a temporary dust cloud in front of the star.

[skysurfer]

I found a possible answer in the same largest online astronomy textbook.

Luminosity

The stars of the Eta Carinae system are completely obscured by dust and opaque stellar winds, with much of the ultraviolet and visual radiation shifted to infrared. The total electromagnetic radiation across all wavelengths for both stars combined is several million solar luminosities (L☉).[19] The best estimate for the luminosity of the primary is 5 million L☉ making it one of the most luminous stars in the galaxy. The luminosity of Eta Carinae B is particularly uncertain, probably several hundred thousand L☉ and almost certainly no more than 1 million L☉.

The bold text above might explain the reddish hue ?

[alval (Alan)]

It has a reddish hue to me when just using my scope or binos but I’ve also found when you use a uhc (astronomik) filter it actually looks like a bright red LED. Quite spectacular amongst the nebula.
Al

[sn1987a (Barry)]

In my telescope eyepiece the star looks very bright yellow white to me and the surrounding Homunculus Nebula looks like flat Fanta orange https://www.youtube.com/watch?v=Jjmipn3yeIA

[Terry B]

eta Car is not typical of other stars. It is a very bright Ha emitter and this can make it more red looking. The spectrum is also obscured by dust making it appear red. See the attached spectrum that I took some time ago. The Ha line actually extends up to a relative intensity of 25 (see axis) so much brighter than any other line.
Terry