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...
Guardado en:
Autores principales: | , , , , , , , , |
---|---|
Formato: | Articulo |
Lenguaje: | Inglés |
Publicado: |
2009
|
Materias: | |
Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/82740 |
Aporte de: |
id |
I19-R120-10915-82740 |
---|---|
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 |
work_keys_str_mv |
AT grohjh bonafidestrongvariablegalacticluminousbluevariablestarsarefastrotatorsdetectionofahighrotationalvelocityinhrcarinae AT daminelia bonafidestrongvariablegalacticluminousbluevariablestarsarefastrotatorsdetectionofahighrotationalvelocityinhrcarinae AT hillierdj bonafidestrongvariablegalacticluminousbluevariablestarsarefastrotatorsdetectionofahighrotationalvelocityinhrcarinae AT barbarodolfohector bonafidestrongvariablegalacticluminousbluevariablestarsarefastrotatorsdetectionofahighrotationalvelocityinhrcarinae AT fernandezlajuseduardo bonafidestrongvariablegalacticluminousbluevariablestarsarefastrotatorsdetectionofahighrotationalvelocityinhrcarinae AT gamenrobertoclaudio bonafidestrongvariablegalacticluminousbluevariablestarsarefastrotatorsdetectionofahighrotationalvelocityinhrcarinae AT moisesap bonafidestrongvariablegalacticluminousbluevariablestarsarefastrotatorsdetectionofahighrotationalvelocityinhrcarinae AT solivellagladysrebeca bonafidestrongvariablegalacticluminousbluevariablestarsarefastrotatorsdetectionofahighrotationalvelocityinhrcarinae AT teodorom bonafidestrongvariablegalacticluminousbluevariablestarsarefastrotatorsdetectionofahighrotationalvelocityinhrcarinae |
bdutipo_str |
Repositorios |
_version_ |
1764820488581808128 |