Long-Term Evolution of Three Light Bridges Developed on the Same Sunspot. (arXiv:2102.04392v3 [astro-ph.SR] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Grinon_Marin_A/0/1/0/all/0/1">Ana Belén Griñón-Marín</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yabar_A/0/1/0/all/0/1">Adur Pastor Yabar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Centeno_R/0/1/0/all/0/1">Rebecca Centeno</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Socas_Navarro_H/0/1/0/all/0/1">Héctor Socas-Navarro</a>
One important feature of sunspots is the presence of light bridges. These
structures are elongated and bright (as compared to the umbra) features that
seem to be related to the formation and evolution of sunspots. In this work, we
studied the long-term evolution and the stratification of different atmospheric
parameters of three light bridges formed in the same host sunspot by different
mechanisms. To accomplish this, we used data taken with the GREGOR Infrared
Spectrograph installed at the GREGOR telescope. These data were inverted to
infer the physical parameters of the atmosphere where the observed spectral
profiles were formed of the three light bridges. We find that, in general, the
behaviour of the three light bridges is typical of this kind of structure with
the magnetic field strength, inclination, and temperature values between the
values at the umbra and the penumbra. We also find that they are of a
significantly non-magnetic character (particularly at the axis of the light
bridges) as it is deduced from the filling factor. In addition, within the
common behaviour of the physical properties of light bridges, we observe that
each one exhibits a particular behaviour. Another interesting result is that
the light bridge cools down, the magnetic field decreases, and the magnetic
field lines get more inclined higher in the atmosphere. Finally, we studied the
magnetic and non-magnetic line-of-sight velocities of the light bridges. The
former shows that the magnetic component is at rest and, interestingly, its
variation with optical depth shows a bi-modal behaviour. For the line-of-sight
velocity of the non-magnetic component, we see that the core of the light
bridge is at rest or with shallow upflows and clear downflows sinking through
the edges.
One important feature of sunspots is the presence of light bridges. These
structures are elongated and bright (as compared to the umbra) features that
seem to be related to the formation and evolution of sunspots. In this work, we
studied the long-term evolution and the stratification of different atmospheric
parameters of three light bridges formed in the same host sunspot by different
mechanisms. To accomplish this, we used data taken with the GREGOR Infrared
Spectrograph installed at the GREGOR telescope. These data were inverted to
infer the physical parameters of the atmosphere where the observed spectral
profiles were formed of the three light bridges. We find that, in general, the
behaviour of the three light bridges is typical of this kind of structure with
the magnetic field strength, inclination, and temperature values between the
values at the umbra and the penumbra. We also find that they are of a
significantly non-magnetic character (particularly at the axis of the light
bridges) as it is deduced from the filling factor. In addition, within the
common behaviour of the physical properties of light bridges, we observe that
each one exhibits a particular behaviour. Another interesting result is that
the light bridge cools down, the magnetic field decreases, and the magnetic
field lines get more inclined higher in the atmosphere. Finally, we studied the
magnetic and non-magnetic line-of-sight velocities of the light bridges. The
former shows that the magnetic component is at rest and, interestingly, its
variation with optical depth shows a bi-modal behaviour. For the line-of-sight
velocity of the non-magnetic component, we see that the core of the light
bridge is at rest or with shallow upflows and clear downflows sinking through
the edges.
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