Publications


-2023-
  • New rotation period measurements of 67 163 Kepler stars
    • T. Reinhold, A. I. Shapiro, S. K. Solanki, and G. Basri
    Astronomy & Astrophysics, Volume 678, 14 pp., October 2023

  • Modeling Stellar Ca II H and K Emission Variations: Spot Contribution to the S-index
    • K. Sowmya, A. I. Shapiro, L. H. M. Rouppe van der Voort, N. A. Krivova, and S. K. Solanki
    The Astrophysical Journal Letters, Volume 956, Issue 1, 8 pp., October 2023

  • Forward modelling of brightness variations in Sun-like stars. II. Light curves and variability
    • N.-E. Nèmec, A. I. Shapiro, E. Işık, S. K. Solanki, and T. Reinhold
    Astronomy & Astrophysics, Volume 672, 10 pp., April 2023

  • Small-scale dynamo in cool stars. II. The effect of metallicity
    • V. Witzke, H. B Duehnen, A. I. Shapiro, D. Przybylski, T. S. Bhatia, R. H. Cameron, and S. K. Solanki
    Astronomy & Astrophysics, Volume 669,13 pp, January 2023

    -2022-

  • Can 1D Radiative-equilibrium Models of Faculae Be Used for Calculating Contamination of Transmission Spectra?
    • V. Witzke, A. I. Shapiro, N. M. Kostogryz, R. H. Cameron, B. V. Rackham, S. Seager,S. K. Solanki and Y. C. Unruh
    The Astrophysical Journal Letters,Volume 941, Issue 2, id.L35, 5 pp., December 2022

  • Superflares on solar-like stars. A new method for identifying the true flare sources in photometric surveys
    • V. Vasilyev,T. Reinhold, A. I. Shapiro, N. A. Krivova, I. Usoskin, B. T. Montet, S. K. Solanki, and Gizon, L.
    Astronomy & Astrophysics, Volume 668, 17 pp, December 2022

  • Measuring Periods in Aperiodic Light Curves-Applying the GPS Method to Infer the Rotation Periods of Solar-like Stars
    • T. Reinhold, A. I. Shapiro, S. K. Solanki, and G. Basri, Gibor
    The Astrophysical Journal Letters, Volume 938, Issue 1, 7 pp, October 2022

  • Faculae Cancel out on the Surfaces of Active Suns
    • N.-E. Nèmec, A. I. Shapiro, E. Işık, K. Sowmya, S. K. Solanki, N. A. Krivova, R. H. Cameron, and L.Gizon
    The Astrophysical Journal Letters, Volume 934, Issue 2, 7 pp, August 2022

  • Predictions of Astrometric Jitter for Sun-like Stars. III. Fast Rotators
    • K. Sowmya, N.-E. Nèmec, A. I. Shapiro E. Işık, E, N. A. Krivova, and S. K. Solanki
    The Astrophysical Journal, Volume 934, Issue 2, 21 pp, August 2022

  • Magnetized supersonic downflows in the chromosphere. A statistical study using the He I 10 830 Å lines
    • K. Sowmya, A. Lagg, S. K. Solanki, and J. S. Castellanos Durán
    Astronomy & Astrophysics, Volume 661, 23 pp, May 2022

  • Multiwavelength Mitigation of Stellar Activity in Astrometric Planet Detection
    • A. Kaplan-Lipkin, B.Macintosh, A. Madurowicz, K. Sowmya, A. I. Shapiro, N. A. Krivova, and S. K. Solanki search by orcid
    The Astronomical Journal, Volume 163, Issue 5, 11 pp, May 2022

  • Rieger-type cycles on the solar-like star KIC 2852336
    • E. Gurgenashvili, T. V. Zaqarashvili, V. Kukhianidze, A. Reiners, T. Reinhold, and A. F. Lanza
    Astronomy & Astrophysics, Volume 660, 7 pp, April 2022

    -2021-

  • Magnetic and Rotational Evolution of ρ CrB from Asteroseismology with TESS
    • T. S.Metcalfe, J. L. van Saders, S. Basu,D. Buzasi, J. J. Drake, R. Egeland, D. Huber, S. H. Saar, K. G. Stassun, W. H. Ball, T. L. Campante, A. J. Finley, O. Kochukhov, S. Mathur, T. Reinhold, V. See, S. Baliunas, and W. Soon
    The Astrophysical Journal, Volume 921, Issue 2, 10 pp., November 2021

  • Predictions of Astrometric Jitter for Sun-like Stars. II. Dependence on Inclination, Metallicity, and Active-Region Nesting
    • K. Sowmya, N.-E. Nèmec, A. I. Shapiro, E. Işık, V. Witzke, N. A. Krivova, and S. K. Solanki
    The Astrophysical Journal, Volume 919, Issue 2, 21 pp., October 2021

  • Rieger-type periodicity in the total irradiance of the Sun as a star during solar cycles 23-24
    • E. Gurgenashvili, T. V. Zaqarashvili, V. Kukhianidze, A. Reiners, R. Oliver, A. F. Lanza, and T.Reinhold
    Astronomy & Astrophysics, Volume 653, 8 pp., September 2021

  • MPS-ATLAS: A fast all-in-one code for synthesising stellar spectra
    • V. Witzke, A. I. Shapiro, M. Cernetic, R. V. Tagirov, N. M. Kostogryz, L. S. Anuhsa, Y. C. Unruh, S. K. Solanki, and R. L. Kurucz
    Astronomy & Astrophysics, Volume 653, 22 pp., September 2021

  • Radiative Transfer with Opacity Distribution Functions: Application to Narrowband Filters
    • L. S. Anusha, V. Witzke, M. Cernetic, A. I. Shapiro, S. K. Solanki, and L. Gizon
    The Astrophysical Journal Supplement Series, Volume 255, Issue 1, 3, 12 pp, July 2021

  • Modeling Stellar Ca II H and K Emission Variations. I. Effect of Inclination on the S-index
    • K. Sowmya, A. I. Shapiro, V. Witzke, N.-E. Nèmec, T. Chatzistergos, K. L. Yeo, N. A. Krivova, and S. K. Solanki
    The Astrophysical Journal, Volume 914, Issue 1, page 21, June 2021

  • Irradiance Variations of the Sun and Sun-Like Stars - Overview of Topical Collection
    • G. Kopp and A. I. Shapiro
    Solar Physics, Volume 296, Issue 4, article 60, April 2021

  • Predictions of Astrometric Jitter for Sun-like Stars. I. The Model and Its Application to the Sun as Seen from the Ecliptic
    • A. I. Shapiro, S. K. Solanki, and N. A. Krivova
    The Astrophysical Journal, Volume 908, Issue 2, 223, 9 pp., February 2021

  • Where Have All the Solar-like Stars Gone? Rotation Period Detectability at Various Inclinations and Metallicities
    • T. Reinhold, A. I. Shapiro, V. Witzke, N.-E. Nèmec, E. Işık, and S. K. Solanki
    The Astrophysical Journal Letters, Volume 908, Issue 2, L21, 9 pp, February 2021

  • Exploring the solar paradigm to explain stellar variability
    • N.-E. Nèmec
    Dissertation, January 2021

    -2020-

  • Inflection point in the power spectrum of stellar brightness variations. III. Facular versus spot dominance on stars with known rotation periods
    • E. M. Amazo-Gómez, A. I. Shapiro, S. K. Solanki, G. Kopp, M. Oshagh, T. Reinhold, and A. Reiners
    Astronomy & Astrophysics, Volume 642, A225, 10 pp., October 2020

  • Understanding the brightness variations of Sun-like stars on timescales of stellar rotation
    • E. M. Amazo-Gómez
    Dissertation, October 2020

  • Amplification of Brightness Variability by Active-region Nesting in Solar-like Stars
    • E. Işık, A. I. Shapiro, S. K. Solanki, and N. A. Krivova
    The Astrophysical Journal Letters, Volume 901, Issue 1, L12, 7 pp., September 2020

  • The Evolution of Rotation and Magnetic Activity in 94 Aqr Aa from Asteroseismology with TESS
    • T. S. Metcalfe, J. L. van Saders, S. Basu, D. Buzasi6, W. J. Chaplin, R. Egeland, R. A. Garcia, P. Gaulme, D. Huber, T.Reinhold, H. Schunker, K. G. Stassun, T. Appourchaux, W. H. Ball, T. R. Bedding, S. Deheuvels, L. González-Cuesta, R. Handberg, A. Jiménez, H. Kjeldsen, T.Li, M. N. Lund, S. Mathur, B. Mosser, M. B. Nielsen, A. Noll, Z. Çelik Orhan, S. Örtel, Â.R. G. Santos, M. Yildiz, S. Baliunas, and W. Soon
    The Astrophysical Journal, Volume 900, Issue 2, 154, 11 pp., September 2020

  • Importance of Angle-dependent Partial Frequency Redistribution in Hyperfine Structure Transitions Under the Incomplete Paschen-Back Effect Regime
    • K. N. Nagendra, K. Sowmya, M. Sampoorna, J. O. Stenflo, and L. S. Anusha
    The Astrophysical Journal, Volume 898, Issue 1, page 49, July 2020

  • Connection measurements of solar and stellar brightness variations
    • N.-E. Nèmec, E. Işık, A. I. Shapiro, S. K. Solanki, N. A. Krivova, and Y. C. Unruh
    Astronomy & Astrophysics, Volume 638, A56, 8 pp., June 2020

  • Solar-type Stars Observed by LAMOST and Kepler
    • J. Zhang, A. I. Shapiro, S. Bi, M. Xiang, T. Reinhold, K. Sowmya, Y. Li, T. Li, M. Du, and X. Zhang
    The Astrophysical Journal Letters, Volume 894, Issue 1, L11, 7 pp., May 2020

  • The Sun is less active than other solar-like stars
    • T. Reinhold, A. I. Shapiro, S. K. Solanki, B. T. Montet, N. A. Krivova, R. H. Cameron, and E. M. Amazo-Gómez
    Science, Volume 368, Issue 6490, pp. 518-521, May 2020

  • Solar-cycle irradiance variations over the last four billion years
    • A. V. Shapiro, A. I. Shapiro, L. Gizon, N. A. Krivova, and S. K. Solanki
    Astronomy & Astrophysics, Volume 636, A83, 8 pp., April 2020

  • Inflection point in the power spectrum of stellar brightness variations. II. The Sun
    • E. M. Amazo-Gómez, A. I. Shapiro, S. K. Solanki, N. A. Krivova, G. Kopp, T. Reinhold, M. Oshagh, and A. Reiners
    Astronomy & Astrophysics, Volume 636, A69, 15 pp., April 2020

  • Power spectra of solar brightness variations at different inclinations
    • N.-E. Nèmec, A. I. Shapiro, N. A. Krivova, R. V. Tagirov, R. H. Cameron, S. K. Solanki, and S. Dreizler
    Astronomy & Astrophysics, Volume 636, A43, 10 pp., April 2020

  • Stellar rotation periods from K2 Campaigns 0-18. Evidence for rotation period bimodality and simultaneous variability decrease
    • T. Reinhold and S. Hekker
    Astronomy & Astrophysics, Volume 635, A43, 13 pp., March 2020

  • Effect of metallicity on the detectability of rotational periods in solar-like stars
    • V. Witzke,T. Reinhold, A. I. Shapiro, N. A. Krivova, and S. K. Solanki
    Astronomy & Astrophysics, Volume 634,L9, 7 pp., January 2020

  • Inflection point in the power spectrum of stellar brightness variations. I. The model
    • A. I. Shapiro, E. M. Amazo-Gómez, N. A. Krivova, and S. K. Solanki
    Astronomy & Astrophysics, Volume 634,L9, 7 pp., January 2020

    -2019-

  • From solar to stellar brightness variations: The effect of metallicity
    • V. Witzke, A. I. Shapiro, S. K. Solanki, N. A. Krivova , and W. Schmutz
    Astronomy & Astrophysics, Volume 619, A146, 2018 November 19

  • Polarized Line Formation in Arbitrary Strength Magnetic Fields: The Case of a Two-level Atom with Hyperfine Structure Splitting
    • M. Sampoorna, K. N. Nagendra, K. Sowmya, J. O. Stenflo, and L. S. Anusha
    The Astrophysical Journal, Volume 883, Issue 2, page 188, October 2019

  • Opacity distribution functions for stellar spectra synthesis
    • M. Cernetic, A. I. Shapiro, V. Witzke, N. A. Krivova, S. K. Solanki, and R. V. Tagirov
    Astronomy & Astrophysics, Volume 627, July 2019

  • Evolution and characteristics of forced shear flows in polytropic atmospheres:
    large and small Péclet number regimes
    • V. Witzke, L. J. Silvers,and B. Favier
    Monthly Notices of the Royal Astronomical Society, Volume 482, Issue 1, January 2019

  • Transition from spot to faculae domination -- An alternate explanation for the dearth of intermediate Kepler rotation periods
    • T. Reinhold, K. J. Bell, J. Kuszlewicz, S. Hekker, and A. I. Shapiro
    Astronomy & Astrophysics, Volume 621, A21, 14 pp., January 2019

    -2018-

  • Forward modelling of brightness variations in Sun-like stars. I. Emergence and surface transport of magnetic flux
    • E. Işık, S. K. Solanki, N. A. Krivova, and A. I. Shapiro
    Astronomy & Astrophysics, Volume 620, A177, 14 pp., December 2018
  • Revised historical solar irradiance forcing
    • T. Egorova, W. Schmutz, E. Rozanov, A. I. Shapiro , I. Usoskin, J. Beer, R. V. Tagirov , and T. Peter
    Astronomy & Astrophysics, Volume 615, A85, July 2018

  • Response of Solar Irradiance to Sunspot-area Variations
    • T. Dudok de Wit, G. Kopp, S. Shapiro, V. Witzke, and M. Kretzschmar
    The Astrophysical Journal, 853:197 (10pp), February 2018

  • The Influence of Metallicity on Stellar Differential Rotation and Magnetic Activity
    • C. Karoff, T. S. Metcalfe, Â. R. G. Santos, B. T. Montet, H. Isaacson, V. Witzke, A. I. Shapiro, S. Mathur, G. R. Davies, M. N. Lund, R. A. Garcia, A. S. Brun, D. Salabert, P. P. Avelino, J. van Saders, R. Egeland, M. S. Cunha, T. L. Campante, W. J. Chaplin, N. A. Krivova, S. K. Solanki, M. Stritzinger, and M. F. Knudsen
    The Astrophysical Journal, 852:46 (12pp), January 2018

    -2017-

  • Nature of solar brightness variations
    • A. I. Shapiro, S. K. Solanki, N. A. Krivova, R. H. Cameron, K. L. Yeo, and W. K. Schmutz
    Nature Astronomy, Volume 1, p. 612-616, August 2017

    Press-release paper

    Max-Planck Scientists explain why the Sun's brightness vary. (Picture is © NASA/SDO)