Difference between revisions of "Triggers:LBVs"
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| − | Known also as S Dor stars. Exhibit slow changes in brightness with occasional outbursts of substantial mass loss. Very heavy stars, often in binary systems, will evolve to W-R stars. Only a few is known. | + | Known also as S Dor stars. Exhibit slow changes in brightness with occasional outbursts of substantial mass loss. Very heavy stars(>30Msun), often in binary systems, will evolve to W-R stars. Only a few is known. |
Known example: '''Eta Carinae'''. | Known example: '''Eta Carinae'''. | ||
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* Baseline micro-variability: P around 10-20 days, amplitude 0.1-0.2 mag | * Baseline micro-variability: P around 10-20 days, amplitude 0.1-0.2 mag | ||
| + | * Positioned close to "instability strip", thus the pulsating-like variability | ||
* "normal eruptions": 1-2 mag (rise within few months), repeating with period of years or decades the brighter abs.mag the shorter period between eruptions) | * "normal eruptions": 1-2 mag (rise within few months), repeating with period of years or decades the brighter abs.mag the shorter period between eruptions) | ||
* Giant eruptions ("Eta Carinae type") of around 8 mag, once a few centuries!! | * Giant eruptions ("Eta Carinae type") of around 8 mag, once a few centuries!! | ||
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* Spectroscopic variations with period of 5.5 years (probably due to binarity) | * Spectroscopic variations with period of 5.5 years (probably due to binarity) | ||
* X-ray variability | * X-ray variability | ||
| + | * engine of outbursts is not well understood yet | ||
Latest revision as of 15:49, 29 July 2009
Known also as S Dor stars. Exhibit slow changes in brightness with occasional outbursts of substantial mass loss. Very heavy stars(>30Msun), often in binary systems, will evolve to W-R stars. Only a few is known. Known example: Eta Carinae.
<math>M_V \sim -11 \ldots -8</math> mag
- Baseline micro-variability: P around 10-20 days, amplitude 0.1-0.2 mag
- Positioned close to "instability strip", thus the pulsating-like variability
- "normal eruptions": 1-2 mag (rise within few months), repeating with period of years or decades the brighter abs.mag the shorter period between eruptions)
- Giant eruptions ("Eta Carinae type") of around 8 mag, once a few centuries!!
- After giant eruption and fade, the star recovers its brightness as the dust disperses.
- Spectroscopic variations with period of 5.5 years (probably due to binarity)
- X-ray variability
- engine of outbursts is not well understood yet
