KIC 10001893: A pulsating sdB star with multiple trapped modes. (arXiv:1812.05675v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Uzundag_M/0/1/0/all/0/1">M. Uzundag</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Baran_A/0/1/0/all/0/1">A.S. Baran</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ostensen_R/0/1/0/all/0/1">R.H. Østensen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Reed_M/0/1/0/all/0/1">M.D. Reed</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Telting_J/0/1/0/all/0/1">J.H. Telting</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Quick_B/0/1/0/all/0/1">B.K. Quick</a>
KIC 10001893 is a V1093 Her type pulsating subdwarf-B star, which was
observed extensively by the Kepler spacecraft. It was a part of the survey
searching for compact pulsators in the Kepler field of view. An amplitude
spectrum of the star demonstrates a rich content of g-modes between 102 and 496
{mu}Hz as well as a few p-modes above 2000 {mu}Hz. In total, we found 110
frequencies. The g-mode region contains 104 frequencies, while the p-mode
region contains just six, altogether indicating the hybrid nature of KIC
10001893. The main goal of our analysis was to identify the detected modes and
to find some features, which will significantly help modeling of the star. We
found no multiplets, which points at a pole-on orientation, however, we defined
modal degrees and relative radial orders using asymptotic period spacing.
Eventually, we assigned 32 dipole l = 1 and 18 quadrupole l = 2 modes. The most
remarkable feature we found are trapped modes, which are clearly seen in a
reduce period diagram. It is the first time that three trapped modes are
detected in one pulsating sdB star. Since the more trapped modes we find, the
better sounding of the stellar interior we can do, this feature provides
important constraints on the physical structure of the star. Mode trapping is
likely caused by the He-H transition region and therefore it provides crucial
constraints for making realistic theoretical models of hot subdwarfs.
KIC 10001893 is a V1093 Her type pulsating subdwarf-B star, which was
observed extensively by the Kepler spacecraft. It was a part of the survey
searching for compact pulsators in the Kepler field of view. An amplitude
spectrum of the star demonstrates a rich content of g-modes between 102 and 496
{mu}Hz as well as a few p-modes above 2000 {mu}Hz. In total, we found 110
frequencies. The g-mode region contains 104 frequencies, while the p-mode
region contains just six, altogether indicating the hybrid nature of KIC
10001893. The main goal of our analysis was to identify the detected modes and
to find some features, which will significantly help modeling of the star. We
found no multiplets, which points at a pole-on orientation, however, we defined
modal degrees and relative radial orders using asymptotic period spacing.
Eventually, we assigned 32 dipole l = 1 and 18 quadrupole l = 2 modes. The most
remarkable feature we found are trapped modes, which are clearly seen in a
reduce period diagram. It is the first time that three trapped modes are
detected in one pulsating sdB star. Since the more trapped modes we find, the
better sounding of the stellar interior we can do, this feature provides
important constraints on the physical structure of the star. Mode trapping is
likely caused by the He-H transition region and therefore it provides crucial
constraints for making realistic theoretical models of hot subdwarfs.
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