Bona fide, strong-variable galactic luminous blue variable stars are fast rotators: Detection of a high rotational velocity in HR Carinae
We report optical observations of the luminous blue variable (LBV) HR Carinae which show that the star has reached a visual minimum phase in 2009. More importantly, we detected absorptions due to SiIV λλ4088-4116. To match their observed line profiles from 2009 May, a high rotational velocity of v r...
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| Autores principales: | , , , , , , , , |
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| Formato: | Articulo |
| Lenguaje: | Inglés |
| Publicado: |
2009
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| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/82740 |
| Aporte de: |
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I19-R120-10915-82740 |
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| record_format |
dspace |
| institution |
Universidad Nacional de La Plata |
| institution_str |
I-19 |
| repository_str |
R-120 |
| collection |
SEDICI (UNLP) |
| language |
Inglés |
| topic |
Ciencias Astronómicas Stars: atmospheres Stars: individual (HR Carinae) Stars: mass loss Stars: rotation Stars: variables: other Supergiants |
| spellingShingle |
Ciencias Astronómicas Stars: atmospheres Stars: individual (HR Carinae) Stars: mass loss Stars: rotation Stars: variables: other Supergiants Groh, J. H. Damineli, A. Hillier, D. J. Barbá, Rodolfo Héctor Fernández Lajús, Eduardo Gamen, Roberto Claudio Moisés, A. P. Solivella, Gladys Rebeca Teodoro, M. Bona fide, strong-variable galactic luminous blue variable stars are fast rotators: Detection of a high rotational velocity in HR Carinae |
| topic_facet |
Ciencias Astronómicas Stars: atmospheres Stars: individual (HR Carinae) Stars: mass loss Stars: rotation Stars: variables: other Supergiants |
| description |
We report optical observations of the luminous blue variable (LBV) HR Carinae which show that the star has reached a visual minimum phase in 2009. More importantly, we detected absorptions due to SiIV λλ4088-4116. To match their observed line profiles from 2009 May, a high rotational velocity of v rot ≃ 150 ∼ 20 km s<SUP>-1</SUP> is needed (assuming an inclination angle of 30°), implying that HR Car rotates at ≃0.88 ∼ 0.2 of its critical velocity for breakup (v<SUB>crit</SUB>). Our results suggest that fast rotation is typical in all strong-variable, bona fide galactic LBVs, which present S-Dor-type variability. Strong-variable LBVs are located in a well-defined region of the HR diagram during visual minimum (the "LBV minimum instability strip"). We suggest this region corresponds to where v crit is reached. To the left of this strip, a forbidden zone with v<SUB>rot</SUB>/v<SUB>crit</SUB>>1 is present, explaining why no LBVs are detected in this zone. Since dormant/ex LBVs like P Cygni and HD 168625 have low v rot, we propose that LBVs can be separated into two groups: fast-rotating, strong-variable stars showing S-Dor cycles (such as AG Car and HR Car) and slow-rotating stars with much less variability (such as P Cygni and HD 168625). We speculate that supernova (SN) progenitors which had S-Dor cycles before exploding (such as in SN 2001ig, SN 2003bg, and SN 2005gj) could have been fast rotators. We suggest that the potential difficulty of fast-rotating Galactic LBVs to lose angular momentum is additional evidence that such stars could explode during the LBV phase. |
| format |
Articulo Articulo |
| author |
Groh, J. H. Damineli, A. Hillier, D. J. Barbá, Rodolfo Héctor Fernández Lajús, Eduardo Gamen, Roberto Claudio Moisés, A. P. Solivella, Gladys Rebeca Teodoro, M. |
| author_facet |
Groh, J. H. Damineli, A. Hillier, D. J. Barbá, Rodolfo Héctor Fernández Lajús, Eduardo Gamen, Roberto Claudio Moisés, A. P. Solivella, Gladys Rebeca Teodoro, M. |
| author_sort |
Groh, J. H. |
| title |
Bona fide, strong-variable galactic luminous blue variable stars are fast rotators: Detection of a high rotational velocity in HR Carinae |
| title_short |
Bona fide, strong-variable galactic luminous blue variable stars are fast rotators: Detection of a high rotational velocity in HR Carinae |
| title_full |
Bona fide, strong-variable galactic luminous blue variable stars are fast rotators: Detection of a high rotational velocity in HR Carinae |
| title_fullStr |
Bona fide, strong-variable galactic luminous blue variable stars are fast rotators: Detection of a high rotational velocity in HR Carinae |
| title_full_unstemmed |
Bona fide, strong-variable galactic luminous blue variable stars are fast rotators: Detection of a high rotational velocity in HR Carinae |
| title_sort |
bona fide, strong-variable galactic luminous blue variable stars are fast rotators: detection of a high rotational velocity in hr carinae |
| publishDate |
2009 |
| url |
http://sedici.unlp.edu.ar/handle/10915/82740 |
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Repositorios |
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