Transgressions:

Sütterlin, Nicole A.

doi:10.2307/j.ctv1nhhxr.12

Cited by 4 publications

(4 citation statements)

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“…The photospheric and spot spectra are T eff = 5800 K and ∆T sp = 500, respectively. Note that ∆T sp = 500 is more representative of the average brightness temperature of the combined umbral and penumbral regions; the darkest umbral regions in sunspots typically have temperatures ≈ 1000 − 1500 K lower than the surrounding photosphere (Sütterlin & Wiehr 1998).…”

Section: The Sun As a Test Casementioning

confidence: 99%

The Effects of Stellar Activity on Optical High-resolution Exoplanet Transmission Spectra

Cauley

Kuckein

Redfield

et al. 2018

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Chromospherically sensitive atomic lines display different spectra in stellar active regions, spots, and the photosphere, raising the possibility that exoplanet transmission spectra are contaminated by the contrast between various portions of the stellar disk. To explore this effect, we performed transit simulations of G and K-type stars for the spectral lines Ca II K at 3933Å, Na I 5890Å, H I 6563 A (Hα), and He I 10830Å. We find that strong facular emission and large coverage fractions can contribute a non-negligible amount to transmission spectra, especially for Hα, Ca II K, and Na I D, while spots and filaments are comparatively unimportant. The amount of contamination depends strongly on the location of the active regions and the intrinsic emission strength. In particular, active regions must be concentrated along the transit chord in order to produce a consistent in-transit signal. Mean absorption signatures in Na I and Hα for example, can reach ≈ 0.2% and 0.3%, respectively, for transits of active latitudes with line emission similar in strength to moderate solar flares. Transmission spectra of planets transiting active stars, such as HD 189733, are likely contaminated by the contrast effect, although the tight constraints on active region geometry and emission strength make it unlikely that consistent in-transit signatures are due entirely to the contrast effect. He I 10830Å is not strongly affected and absorption signatures are likely diluted, rather than enhanced, by stellar activity. He I 10830Å should thus be considered a priority for probing extended atmospheres, even in the case of active stars.

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Section: The Sun As a Test Casementioning

confidence: 99%

The Effects of Stellar Activity on Optical High-resolution Exoplanet Transmission Spectra

Cauley

Kuckein

Redfield

et al. 2018

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“…Furthermore, due to their limited size, and thus their inability to efficiently inhibit the surrounding convective motions on long-term time scales, solar pores often display minimal signatures at higher atmospheric heights (transition region and corona). Sütterlin (1998) and Sütterlin & Wiehr (1998) employed full-Stokes analysis of pore structures and found that they displayed a vertical magnetic field gradient of ∼ 5 G km −1 , marginally inflated when compared to large-scale sunspots (1-3 G km −1 ; Pahlke & Wiehr 1990;Bruls et al 1995;Rüedi et al 1995;Berlicki et al 2006), thus depleting their observational (and magnetic) signatures rapidly as one moves away from the photospheric layer. Nevertheless, pore structures provide observers with one of the most idealised wave conduits in the lower solar atmosphere: a nearly circularly symmetric waveguide that is heavily susceptible to external motions, buffeting and driving forces.…”

Section: Active Regionsmentioning

confidence: 99%

Multiwavelength Studies of MHD Waves in the Solar Chromosphere

et al. 2015

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The chromosphere is a thin layer of the solar atmosphere that bridges the relatively cool photosphere and the intensely heated transition region and corona. Compressible and incompressible waves propagating through the chromosphere can supply significant amounts of energy to the interface region and corona. In recent years an abundance of high-resolution observations from state-of-the-art facilities have provided new and exciting ways of disentangling the characteristics of oscillatory phenomena propagating through the dynamic chromosphere. Coupled with rapid advancements in magnetohydrodynamic wave theory, we are now in an ideal position to thoroughly investigate the role waves play in supplying energy to sustain chromospheric and coronal heating. Here, we review the recent progress made in characterising, categorising and interpreting oscillations manifesting in the solar chromosphere, with an impetus placed on their intrinsic energetics.

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“…The curved retinal surface and spatial extent of the niche pose a further challenge. We overcome these challenges by comparing experimental clonal data with simulated clonal data from a 3D agent based cell-center overlapping spheres model built in the platform EPISIM (Sütterlin et al, 2013; Sütterlin et al, 2017; Sütterlin, 2019). This modelling technique represents cells as discrete objects ( e.g.…”

Section: Resultsmentioning

confidence: 99%

“…Excerpt of the relevant parts of EPISIM Simulator source code. The full source code is available at https://gitlab.com/EPISIM/EPISIM-Simulator (Sütterlin, 2019; copy archived at https://github.com/elifesciences-publications/EPISIM-Simulator). …”

Section: Additional Filesmentioning

confidence: 99%

Retinal stem cells modulate proliferative parameters to coordinate post-embryonic morphogenesis in the eye of fish

Tsingos

Höckendorf

Sütterlin

et al. 2019

eLife

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Combining clonal analysis with a computational agent based model, we investigate how tissue-specific stem cells for neural retina (NR) and retinal pigmented epithelium (RPE) of the teleost medaka (Oryzias latipes) coordinate their growth rates. NR cell division timing is less variable, consistent with an upstream role as growth inducer. RPE cells divide with greater variability, consistent with a downstream role responding to inductive signals. Strikingly, the arrangement of the retinal ciliary marginal zone niche results in a spatially biased random lineage loss, where stem- and progenitor cell domains emerge spontaneously. Further, our data indicate that NR cells orient division axes to regulate organ shape and retinal topology. We highlight an unappreciated mechanism for growth coordination, where one tissue integrates cues to synchronize growth of nearby tissues. This strategy may enable evolution to modulate cell proliferation parameters in one tissue to adapt whole-organ morphogenesis in a complex vertebrate organ.

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Transgressions:

Cited by 4 publications

References 0 publications

The Effects of Stellar Activity on Optical High-resolution Exoplanet Transmission Spectra

The Effects of Stellar Activity on Optical High-resolution Exoplanet Transmission Spectra

Multiwavelength Studies of MHD Waves in the Solar Chromosphere

Retinal stem cells modulate proliferative parameters to coordinate post-embryonic morphogenesis in the eye of fish

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