scholarly journals A New Candidate Luminous Blue Variable

2020 ◽  
Vol 901 (1) ◽  
pp. L15
Author(s):  
Donald F. Figer ◽  
Francisco Najarro ◽  
Maria Messineo ◽  
J. Simon Clark ◽  
Karl M. Menten
Keyword(s):  
Luminous Blue Variable

scholarly journals Radiation-Driven Stellar Eruptions

Galaxies ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 10 ◽  
Author(s):  
Kris Davidson
Keyword(s):  
Mass Loss ◽  
Radiation Pressure ◽  
Central Region ◽  
Massive Stars ◽  
Variable Stars ◽  
Blast Waves ◽  
Subsequent Evolution ◽  
Fundamental Causes ◽  
Radiative Output ◽  
Luminous Blue Variable

Very massive stars occasionally expel material in colossal eruptions, driven by continuum radiation pressure rather than blast waves. Some of them rival supernovae in total radiative output, and the mass loss is crucial for subsequent evolution. Some are supernova impostors, including SN precursor outbursts, while others are true SN events shrouded by material that was ejected earlier. Luminous Blue Variable stars (LBV’s) are traditionally cited in relation with giant eruptions, though this connection is not well established. After four decades of research, the fundamental causes of giant eruptions and LBV events remain elusive. This review outlines the basic relevant physics, with a brief summary of essential observational facts. Reasons are described for the spectrum and emergent radiation temperature of an opaque outflow. Proposed mechanisms are noted for instabilities in the star’s photosphere, in its iron opacity peak zones, and in its central region. Various remarks and conjectures are mentioned, some of them relatively unfamiliar in the published literature.

scholarly journals MN112: a new Galactic candidate luminous blue variable

2010 ◽  
Author(s):  
V. V. Gvaramadze ◽  
A. Y. Kniazev ◽  
S. Fabrika ◽  
O. Sholukhova ◽  
L. N. Berdnikov ◽  
...  
Keyword(s):  
Luminous Blue Variable

scholarly journals Multiplicity of Galactic luminous blue variable stars

2021 ◽  
Author(s):  
L. Mahy ◽  
C. Lanthermann ◽  
D. Hutsemékers ◽  
J. Kluska ◽  
A. Lobel ◽  
...  
Keyword(s):  
Variable Stars ◽  
Luminous Blue Variable

The Nature of the Luminous Blue Variable AG Carinae

1994 ◽  
pp. 215-218
Author(s):  
R. Viotti ◽  
A. Cassatella ◽  
V. F. Polcaro ◽  
G. B. Baratta ◽  
A. Damineli Neto ◽  
...  
Keyword(s):  
Luminous Blue Variable

scholarly journals NIKA2 observations around LBV stars Emission from stars and circumstellar material

2020 ◽  
Vol 228 ◽  
pp. 00023
Author(s):  
J. Ricardo Rizzo ◽  
Alessia Ritacco ◽  
Cristobal Bordiu
Keyword(s):  
Thermal Emission ◽  
Continuum Emission ◽  
Core Collapse ◽  
Spectral Indices ◽  
Ionized Gas ◽  
Dark Cloud ◽  
High Frequencies ◽  
Circumstellar Material ◽  
Dark Clouds ◽  
Luminous Blue Variable

Luminous Blue Variable (LBV) stars are evolved massive objects, previous to core-collapse supernova. LBVs are characterized by photometric and spectroscopic variability, produced by strong and dense winds, mass-loss events and very intense UV radiation. LBVs strongly disturb their surroundings by heating and shocking, and produce important amounts of dust. The study of the circumstellar material is therefore crucial to understand how these massive stars evolve, and also to characterize their effects onto the interstellar medium. The versatility of NIKA2 is a key in providing simultaneous observations of both the stellar continuum and the extended, circumstellar contribution. The NIKA2 frequencies (150 and 260 GHz) are in the range where thermal dust and free-free emission compete, and hence NIKA2 has the capacity to provide key information about the spatial distribution of circumstellar ionized gas, warm dust and nearby dark clouds; non-thermal emission is also possible even at these high frequencies. We show the results of the first NIKA2 survey towards five LBVs. We detected emission from four stars, three of them immersed in tenuous circumstellar material. The spectral indices show a complex distribution and allowed us to separate and characterize different components. We also found nearby dark clouds, with spectral indices typical of thermal emission from dust. Spectral indices of the detected stars are negative and hard to be explained only by free-free processes. In one of the sources, G79.29+0.46, we also found a strong correlation of the 1mm and 2mm continuum emission with respect to nested molecular shells at ≈1 pc from the LBV. The spectral index in this region clearly separates four components: the LBV star, a bubble characterized by free-free emission, and a shell interacting with a nearby infrared dark cloud.

scholarly journals Spectroscopic and photometric oscillatory envelope variability during the S Doradus outburst of the luminous blue variable R71

2017 ◽  
Vol 608 ◽  
pp. A124 ◽  
Author(s):  
A. Mehner ◽  
D. Baade ◽  
J. H. Groh ◽  
T. Rivinius ◽  
F.-J. Hambsch ◽  
...  
Keyword(s):  
Luminous Blue Variable

scholarly journals Special session on HD 5980

1999 ◽  
Vol 193 ◽  
pp. 770-771
Author(s):  
Anthony F.J. Moffat
Keyword(s):  
Special Session ◽  
Regular Meeting ◽  
Luminous Blue Variable

On Monday before the regular meeting began, a group of 31 participants met for 5 hours to discuss HD 5980, a massive binary in which one of its components erupted in 1994 as a luminous blue variable (LBV). This made HD 5980 the most luminous star in all the SMC for about six months. The highlights of this session are presented here.

scholarly journals A new and unusual LBV-like outburst from a Wolf–Rayet star in the outskirts of M33

2020 ◽  
Vol 492 (4) ◽  
pp. 5897-5915 ◽  
Author(s):  
Nathan Smith ◽  
Jennifer E Andrews ◽  
Maxwell Moe ◽  
Peter Milne ◽  
Christopher Bilinski ◽  
...  
Keyword(s):  
Wind Speed ◽  
Light Curve ◽  
Spectral Type ◽  
Fold Increase ◽  
Small Magellanic Cloud ◽  
Bolometric Luminosity ◽  
Type Spectrum ◽  
Low Metallicity ◽  
Rayet Star ◽  
Luminous Blue Variable

ABSTRACT MCA-1B (also called UIT003) is a luminous hot star in the western outskirts of M33, classified over 20 yr ago with a spectral type of Ofpe/WN9 and identified then as a candidate luminous blue variable (LBV). Palomar Transient Factory data reveal that this star brightened in 2010, with a light curve resembling that of the classic LBV star AF And in M31. Other Ofpe/WN9 stars have erupted as LBVs, but MCA-1B was unusual because it remained hot. It showed a WN-type spectrum throughout its eruption, whereas LBVs usually get much cooler. MCA-1B showed an almost four-fold increase in bolometric luminosity and a doubling of its radius, but its temperature stayed ≳29 kK. As it faded, it shifted to even hotter temperatures, exhibiting a WN7/WN8-type spectrum, and doubling its wind speed. MCA-1B is reminiscent of some supernova impostors, and its location resembles the isolated environment of SN 2009ip. It is most similar to HD 5980 (in the Small Magellanic Cloud) and GR 290 (also in M33). Whereas these two LBVs exhibited B-type spectra in eruption, MCA-1B is the first clear case where a Wolf–Rayet (WR) spectrum persisted at all times. Together, MCA-1B, HD 5980, and GR 290 constitute a class of WN-type LBVs, distinct from S Doradus LBVs. They are most interesting in the context of LBVs at low metallicity, a possible post-LBV/WR transition in binaries, and as likely Type Ibn supernova progenitors.

scholarly journals A New Luminous Blue Variable in the Outskirts of the Andromeda Galaxy

2019 ◽  
Vol 884 (1) ◽  
pp. L7 ◽  
Author(s):  
Y. Huang ◽  
H.-W. Zhang ◽  
C. Wang ◽  
B.-Q. Chen ◽  
Y.-W. Zhang ◽  
...  
Keyword(s):  
Andromeda Galaxy ◽  
Luminous Blue Variable
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