Imperial College London
Dr Yvonne Unruh

DrYvonneUnruh

Faculty of Natural Sciences, Department of Physics

Reader in Astrophysics
 
 
 
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Contact

 

y.unruh Website

 
 
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Location

 

1114Blackett LaboratorySouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Nemec:2020:0004-6361/202038054,
author = {Nemec, N-E and Isik, E and Shapiro, AI and Solanki, SK and Krivova, NA and Unruh, Y},
doi = {0004-6361/202038054},
journal = {Astronomy and Astrophysics: a European journal},
pages = {1--8},
title = {Connecting measurements of solar and stellar brightness variations},
url = {http://dx.doi.org/10.1051/0004-6361/202038054},
volume = {638},
year = {2020}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Context. A comparison of solar and stellar brightness variations is hampered by the difference in spectral passbands that are used in observations, and also by the possible difference in the inclination of the solar and stellar rotation axes from the line of sight.Aims. We calculate the rotational variability of the Sun as it would be measured in passbands used for stellar observations. In particular, we consider the filter systems used by the CoRoT, Kepler, TESS, and Gaia space missions. We also quantify the effect of the inclination of the rotation axis on the solar rotational variability.Methods. We employed the spectral and total irradiance reconstruction (SATIRE) model to calculate solar brightness variations in different filter systems as observed from the ecliptic plane. We then combined the simulations of the surface distribution of the magnetic features at different inclinations using a surface flux transport model with the SATIRE calculations to compute the dependence of the variability on the inclination.Results. For an ecliptic-bound observer, the amplitude of the solar rotational variability, as observed in the total solar irradiance (TSI), is 0.68 mmag (averaged over solar cycles 21–24). We obtained corresponding amplitudes in the Kepler (0.74 mmag), CoRoT (0.73 mmag), TESS (0.62 mmag), Gaia G (0.74 mmag), Gaia GRP (0.62 mmag), and Gaia GBP (0.86 mmag) passbands. Decreasing the inclination of the rotation axis decreases the rotational variability. For a sample of randomly inclined stars, the variability is on average 15% lower in all filter systems we considered. This almost compensates for the difference in amplitudes of the variability in TSI and Kepler passbands, making the amplitudes derived from the TSI records an ideal representation of the solar rotational variability for comparison to Kepler stars with unknown inclinations.Conclusions. The TSI appears to be a relatively good measure of solar variability for comparisons with stellar measur
AU  - Nemec,N-E
AU  - Isik,E
AU  - Shapiro,AI
AU  - Solanki,SK
AU  - Krivova,NA
AU  - Unruh,Y
DO  - 0004-6361/202038054
EP  - 8
PY  - 2020///
SN  - 0004-6361
SP  - 1
TI  - Connecting measurements of solar and stellar brightness variations
T2  - Astronomy and Astrophysics: a European journal
UR  - http://dx.doi.org/10.1051/0004-6361/202038054
UR  - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000541159800004&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
UR  - https://www.aanda.org/articles/aa/abs/2020/06/aa38054-20/aa38054-20.html
UR  - http://hdl.handle.net/10044/1/80452
VL  - 638
ER  -
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