The Sun is less active than other solar-like stars
Activity levels of Sun-like stars
Magnetic activity on the Sun leads to solar flares, coronal mass ejections, and other space weather that affects Earth. Similar activity on other stars may determine the habitability of any orbiting exoplanets. Reinhold et al. analyzed brightness variations of stars observed with the Kepler and Gaia space telescopes to infer their activity levels (see the Perspective by Santos and Mathur). They found that the Sun was less active than most of the 369 solar-type stars in their sample (those with the most similar physical properties). It remains unclear whether the Sun is permanently less active than other stars of its type or if its activity levels vary over many thousands or millions of years.
Abstract
The magnetic activity of the Sun and other stars causes their brightness to vary. We investigated how typical the Sun’s variability is compared with other solar-like stars, i.e., those with near-solar effective temperatures and rotation periods. By combining 4 years of photometric observations from the Kepler space telescope with astrometric data from the Gaia spacecraft, we were able to measure photometric variabilities of 369 solar-like stars. Most of those with well-determined rotation periods showed higher variability than the Sun and are therefore considerably more active. These stars appear nearly identical to the Sun except for their higher variability. Therefore, we speculate that the Sun could potentially also go through epochs of such high variability.
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Supplementary Material
Summary
Materials and Methods
Figs. S1 to S10
Data S1
Resources
References and Notes
1
A. Reiners, Observations of cool-star magnetic fields. Living Rev. Sol. Phys. 9, 1 (2012).
2
S. K. Solanki, N. A. Krivova, J. D. Haigh, Solar irradiance variability and climate. Annu. Rev. Astron. Astrophys. 51, 311–351 (2013).
3
G. Bond, B. Kromer, J. Beer, R. Muscheler, M. N. Evans, W. Showers, S. Hoffmann, R. Lotti-Bond, I. Hajdas, G. Bonani, Persistent solar influence on North Atlantic climate during the Holocene. Science 294, 2130–2136 (2001).
4
S. Wang, Q. Zhang, L. Millán, K.-F. Li, Y. L. Yung, S. P. Sander, N. J. Livesey, M. L. Santee, First evidence of middle atmospheric HO2 response to 27 day solar cycles from satellite observations. Geophys. Res. Lett. 42, 10,004–10,009 (2015).
5
G. Kopp, An assessment of the solar irradiance record for climate studies. J. Space Weather. Space Clim. 4, A14 (2014).
6
M. Dasi-Espuig, J. Jiang, N. A. Krivova, S. K. Solanki, Modelling total solar irradiance since 1878 from simulated magnetograms. Astron. Astrophys. 570, A23 (2014).
7
I. G. Usoskin, A history of solar activity over millennia. Living Rev. Sol. Phys. 14, 3 (2017).
8
C.-J. Wu, N. A. Krivova, S. K. Solanki, I. G. Usoskin, Solar total and spectral irradiance reconstruction over the last 9000 years. Astron. Astrophys. 620, A120 (2018).
9
G. Basri, L. M. Walkowicz, A. Reiners, Comparison of Kepler photometric variability with the sun on different timescales. Astrophys. J. 769, 37 (2013).
10
R. R. Radick, G. W. Lockwood, G. W. Henry, J. C. Hall, A. A. Pevtsov, Patterns of variation for the sun and sun-like stars. Astrophys. J. 855, 75 (2018).
11
C. Karoff, M. F. Knudsen, P. De Cat, A. Bonanno, A. Fogtmann-Schulz, J. Fu, A. Frasca, F. Inceoglu, J. Olsen, Y. Zhang, Y. Hou, Y. Wang, J. Shi, W. Zhang, Observational evidence for enhanced magnetic activity of superflare stars. Nat. Commun. 7, 11058 (2016).
12
D. Salabert, R. A. García, A. Jiménez, L. Bertello, E. Corsaro, P. L. Pallé, Photospheric activity of the Sun with VIRGO and GOLF. Astron. Astrophys. 608, A87 (2017).
13
Materials and methods are available as supplementary materials.
14
P. Foukal, Stellar luminosity variations and global warming. Science 264, 238–239 (1994).
15
V. Witzke, A. I. Shapiro, S. K. Solanki, N. A. Krivova, W. Schmutz, From solar to stellar brightness variations. Astron. Astrophys. 619, A146 (2018).
16
W. J. Borucki, D. Koch, G. Basri, N. Batalha, T. Brown, D. Caldwell, J. Caldwell, J. Christensen-Dalsgaard, W. D. Cochran, E. DeVore, E. W. Dunham, A. K. Dupree, T. N. Gautier 3rd, J. C. Geary, R. Gilliland, A. Gould, S. B. Howell, J. M. Jenkins, Y. Kondo, D. W. Latham, G. W. Marcy, S. Meibom, H. Kjeldsen, J. J. Lissauer, D. G. Monet, D. Morrison, D. Sasselov, J. Tarter, A. Boss, D. Brownlee, T. Owen, D. Buzasi, D. Charbonneau, L. Doyle, J. Fortney, E. B. Ford, M. J. Holman, S. Seager, J. H. Steffen, W. F. Welsh, J. Rowe, H. Anderson, L. Buchhave, D. Ciardi, L. Walkowicz, W. Sherry, E. Horch, H. Isaacson, M. E. Everett, D. Fischer, G. Torres, J. A. Johnson, M. Endl, P. MacQueen, S. T. Bryson, J. Dotson, M. Haas, J. Kolodziejczak, J. Van Cleve, H. Chandrasekaran, J. D. Twicken, E. V. Quintana, B. D. Clarke, C. Allen, J. Li, H. Wu, P. Tenenbaum, E. Verner, F. Bruhweiler, J. Barnes, A. Prsa, Kepler planet-detection mission: Introduction and first results. Science 327, 977–980 (2010).
17
R. L. Gilliland, W. J. Chaplin, E. W. Dunham, V. S. Argabright, W. J. Borucki, G. Basri, S. T. Bryson, D. L. Buzasi, D. A. Caldwell, Y. P. Elsworth, J. M. Jenkins, D. G. Koch, J. Kolodziejczak, A. Miglio, J. van Cleve, L. M. Walkowicz, W. F. Welsh, Kepler mission stellar and instrument noise properties. Astrophys. J. Suppl. Ser. 197, 6 (2011).
18
D. Huber, V. S. Aguirre, J. M. Matthews, M. H. Pinsonneault, E. Gaidos, R. A. García, S. Hekker, S. Mathur, B. Mosser, G. Torres, F. A. Bastien, S. Basu, T. R. Bedding, W. J. Chaplin, B.-O. Demory, S. W. Fleming, Z. Guo, A. W. Mann, J. F. Rowe, A. M. Serenelli, M. A. Smith, D. Stello, Revised stellar properties of Kepler targets for the quarter 1-16 transit detection run. Astrophys. J. Suppl. Ser. 211, 2 (2014).
19
S. Mathur, D. Huber, N. M. Batalha, D. R. Ciardi, F. A. Bastien, A. Bieryla, L. A. Buchhave, W. D. Cochran, M. Endl, G. A. Esquerdo, E. Furlan, A. Howard, S. B. Howell, H. Isaacson, D. W. Latham, P. J. MacQueen, D. R. Silva, Revised stellar properties of Kepler targets for the Q1-17 (DR25) transit detection run. Astrophys. J. Suppl. Ser. 229, 30 (2017).
20
T. Reinhold, A. Reiners, G. Basri, Rotation and differential rotation of active Kepler stars. Astron. Astrophys. 560, A4 (2013).
21
A. McQuillan, T. Mazeh, S. Aigrain, Rotation periods of 34,030 Kepler main-sequence stars: The full autocorrelation sample. Astrophys. J. Suppl. Ser. 211, 24 (2014).
22
Gaia Collaboration, , Gaia data release 1: The Gaia mission. Astron. Astrophys. 595, A1 (2016).
23
C. A. L. Bailer-Jones, J. Rybizki, M. Fouesneau, G. Mantelet, R. Andrae, Estimating distance from parallaxes. IV. Distances to 1.33 billion stars in Gaia data release 2. Astron. J. 156, 58 (2018).
24
Gaia Collaboration, , Gaia data release 2: Summary of the contents and survey properties. Astron. Astrophys. 616, A1 (2018).
25
G. Basri, L. M. Walkowicz, N. Batalha, R. L. Gilliland, J. Jenkins, W. J. Borucki, D. Koch, D. Caldwell, A. K. Dupree, D. W. Latham, S. Meibom, S. Howell, T. Brown, Photometric variability in Kepler target stars: The sun among stars—a first look. Astrophys. J. 713, L155–L159 (2010).
26
J. C. Smith, M. C. Stumpe, J. E. Van Cleve, J. M. Jenkins, T. S. Barclay, M. N. Fanelli, F. R. Girouard, J. J. Kolodziejczak, S. D. McCauliff, R. L. Morris, J. D. Twicken, Kepler presearch data conditioning II: A Bayesian approach to systematic error correction. Publ. Astron. Soc. Pac. 124, 1000–1014 (2012).
27
S. Aigrain, J. Llama, T. Ceillier, M. L. Chagas, J. R. A. Davenport, R. A. García, K. L. Hay, A. F. Lanza, A. McQuillan, T. Mazeh, J. R. de Medeiros, M. B. Nielsen, T. Reinhold, Testing the recovery of stellar rotation signals from Kepler light curves using a blind hare-and-hounds exercise. Mon. Not. R. Astron. Soc. 450, 3211–3226 (2015).
28
A. I. Shapiro, S. K. Solanki, N. A. Krivova, R. H. Cameron, K. L. Yeo, W. K. Schmutz, The nature of solar brightness variations. Nat. Astron. 1, 612–616 (2017).
29
T. Reinhold, K. J. Bell, J. Kuszlewicz, S. Hekker, A. I. Shapiro, Transition from spot to faculae domination. Astron. Astrophys. 621, A21 (2019).
30
H. Maehara, T. Shibayama, S. Notsu, Y. Notsu, T. Nagao, S. Kusaba, S. Honda, D. Nogami, K. Shibata, Superflares on solar-type stars. Nature 485, 478–481 (2012).
31
Y. Notsu, H. Maehara, S. Honda, S. L. Hawley, J. R. A. Davenport, K. Namekata, S. Notsu, K. Ikuta, D. Nogami, K. Shibata, Do Kepler superflare stars really include slowly rotating sun-like stars? Results using APO 3.5 m telescope spectroscopic observations and Gaia-DR2 data. Astrophys. J. 876, 58 (2019).
32
T. S. Metcalfe, R. Egeland, J. van Saders, Stellar evidence that the solar dynamo may be in transition. Astrophys. J. 826, L2 (2016).
33
T. S. Metcalfe, J. van Saders, Magnetic evolution and the disappearance of sun-like activity cycles. Sol. Phys. 292, 126 (2017).
34
A. Bressan, P. Marigo, L. Girardi, B. Salasnich, C. Dal Cero, S. Rubele, A. Nanni, PARSEC: Stellar tracks and isochrones with the PAdova and TRieste stellar evolution code. Mon. Not. R. Astron. Soc. 427, 127–145 (2012).
35
Y. Chen, L. Girardi, A. Bressan, P. Marigo, M. Barbieri, X. Kong, Improving PARSEC models for very low mass stars. Mon. Not. R. Astron. Soc. 444, 2525–2543 (2014).
36
Y. Chen, A. Bressan, L. Girardi, P. Marigo, X. Kong, A. Lanza, PARSEC evolutionary tracks of massive stars up to 350 M☉ at metallicities 0.0001 ≤ Z ≤ 0.04. Mon. Not. R. Astron. Soc. 452, 1068–1080 (2015).
37
J. Tang, A. Bressan, P. Rosenfield, A. Slemer, P. Marigo, L. Girardi, L. Bianchi, New PARSEC evolutionary tracks of massive stars at low metallicity: Testing canonical stellar evolution in nearby star-forming dwarf galaxies. Mon. Not. R. Astron. Soc. 445, 4287–4305 (2014).
38
P. Marigo, L. Girardi, A. Bressan, P. Rosenfield, B. Aringer, Y. Chen, M. Dussin, A. Nanni, G. Pastorelli, T. S. Rodrigues, M. Trabucchi, S. Bladh, J. Dalcanton, M. A. T. Groenewegen, J. Montalbán, P. R. Wood, A new generation of PARSEC–COLIBRI stellar isochrones including the TP-AGB phase. Astrophys. J. 835, 77 (2017).
39
G. Pastorelli, P. Marigo, L. Girardi, Y. Chen, S. Rubele, M. Trabucchi, B. Aringer, S. Bladh, A. Bressan, J. Montalbán, M. L. Boyer, J. J. Dalcanton, K. Eriksson, M. A. T. Groenewegen, S. Höfner, T. Lebzelter, A. Nanni, P. Rosenfield, P. R. Wood, M.-R. L. Cioni, Constraining the thermally pulsing asymptotic giant branch phase with resolved stellar populations in the Small Magellanic Cloud. Mon. Not. R. Astron. Soc. 485, 5666–5692 (2019).
40
M. Weiler, Revised Gaia Data Release 2 passbands. Astron. Astrophys. 617, A138 (2018).
41
Y. Chen, L. Girardi, X. Fu, A. Bressan, B. Aringer, P. Dal Tio, G. Pastorelli, P. Marigo, G. Costa, X. Zhang, YBC: A stellar bolometric corrections database with variable extinction coefficients. Astron. Astrophys. 632, A105 (2019).
42
M. A. T. Groenewegen, The mid- and far-infrared colours of AGB and post-AGB stars. Astron. Astrophys. 448, 181–187 (2006).
43
P. Kroupa, On the variation of the initial mass function. Mon. Not. R. Astron. Soc. 322, 231–246 (2001).
44
P. Kroupa, The initial mass function of stars: Evidence for uniformity in variable systems. Science 295, 82–91 (2002).
45
K. Kinemuchi, M. Fanelli, J. Pepper, M. Still, S. B. Howell, Demystifying Kepler data: A primer for systematic artifact mitigation. Publ. Astron. Soc. Pac. 124, 963–984 (2012).
46
M. C. Stumpe, J. C. Smith, J. E. Van Cleve, J. D. Twicken, T. S. Barclay, M. N. Fanelli, F. R. Girouard, J. M. Jenkins, J. J. Kolodziejczak, S. D. McCauliff, R. L. Morris, Kepler presearch data conditioning I: Architecture and algorithms for error correction in Kepler light curves. Publ. Astron. Soc. Pac. 124, 985–999 (2012).
47
M. C. Stumpe, J. C. Smith, J. H. Catanzarite, J. E. Van Cleve, J. M. Jenkins, J. D. Twicken, F. R. Girouard, Multiscale systematic error correction via wavelet-based bandsplitting in Kepler data. Publ. Astron. Soc. Pac. 126, 100–114 (2014).
48
M. R. Haas, N. M. Batalha, S. T. Bryson, D. A. Caldwell, J. L. Dotson, J. Hall, J. M. Jenkins, T. C. Klaus, D. G. Koch, J. Kolodziejczak, C. Middour, M. Smith, C. K. Sobeck, J. Stober, R. S. Thompson, J. E. Van Cleve, Kepler science operations. Astrophys. J. 713, L115–L119 (2010).
49
A. D. Feinstein, B. T. Montet, D. Foreman-Mackey, M. E. Bedell, N. Saunders, J. L. Bean, J. L. Christiansen, C. Hedges, R. Luger, D. Scolnic, J. V. M. Cardoso, Eleanor: An open-source tool for extracting light curves from the TESS full-frame images. Publ. Astron. Soc. Pac. 131, 094502 (2019).
50
W. Zong, J.-N. Fu, P. D. Cat, J. Shi, A. Luo, H. Zhang, A. Frasca, C. J. Corbally, J. M. Żakowicz, G. Catanzaro, R. O. Gray, J. Wang, Y. Pan, A. Ren, R. Zhang, M. Jin, Y. Wu, S. Dong, J.-W. Xie, W. Zhang, Y. Hou, LAMOST observations in the Kepler field. II. Database of the low-resolution spectra from the five-year regular survey. Astrophys. J. Suppl. Ser. 238, 30 (2018).
51
T. M. Brown, D. W. Latham, M. E. Everett, G. A. Esquerdo, Kepler input catalog: Photometric calibration and stellar classification. Astron. J. 142, 112 (2011).
52
M. H. Pinsonneault, D. An, J. Molenda-Żakowicz, W. J. Chaplin, T. S. Metcalfe, H. Bruntt, A revised effective temperature scale for the Kepler input catalog. Astrophys. J. Suppl. Ser. 199, 30 (2012).
53
L. Casagrande, I. Ramírez, J. Meléndez, M. Bessell, M. Asplund, An absolutely calibrated Teff scale from the infrared flux method. Astron. Astrophys. 512, A54 (2010).
54
G. Basri, L. M. Walkowicz, N. Batalha, R. L. Gilliland, J. Jenkins, W. J. Borucki, D. Koch, D. Caldwell, A. K. Dupree, D. W. Latham, G. W. Marcy, S. Meibom, T. Brown, Photometric variability in Kepler target stars. II. An overview of amplitude, periodicity, and rotation in first quarter data. Astron. J. 141, 20 (2011).
55
D. H. Hathaway, The solar cycle. Living Rev. Sol. Phys. 12, 4 (2015).
56
C. Fröhlich, J. Romero, H. Roth, C. Wehrli, B. N. Andersen, T. Appourchaux, V. Domingo, U. Telljohann, G. Berthomieu, P. Delache, J. Provost, T. Toutain, D. A. Crommelynck, A. Chevalier, A. Fichot, W. Däppen, D. Gough, T. Hoeksema, A. Jiménez, M. F. Gómez, J. M. Herreros, T. Roca Cortés, A. R. Jones, J. M. Pap, R. C. Willson, VIRGO: Experiment for helioseismology and solar irradiance monitoring. Sol. Phys. 162, 101 (1995).
57
N.-E. Nèmec, A. I. Shapiro, N. A. Krivova, S. K. Solanki, R. V. Tagirov, R. H. Cameron, S. Dreizler, Power spectra of solar brightness variations at different inclinations. arXiv:2002.10895 [astro-ph.SR] (25 February 2020).
58
S. Mathur, R. A. García, J. Ballot, T. Ceillier, D. Salabert, T. S. Metcalfe, C. Régulo, A. Jiménez, S. Bloemen, Magnetic activity of F stars observed by Kepler. Astron. Astrophys. 562, A124 (2014).
59
R. W. Noyes, L. W. Hartmann, S. L. Baliunas, D. K. Duncan, A. H. Vaughan, Rotation, convection, and magnetic activity in lower main-sequence stars. Astrophys. J. 279, 763 (1984).
60
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. Saders, R. Egeland, M. S. Cunha, T. L. Campante, W. J. Chaplin, N. Krivova, S. K. Solanki, M. Stritzinger, M. F. Knudsen, The influence of metallicity on stellar differential rotation and magnetic activity. Astrophys. J. 852, 46 (2018).
61
A. I. Shapiro, S. K. Solanki, N. A. Krivova, K. L. Yeo, W. K. Schmutz, Are solar brightness variations faculae- or spot-dominated? Astron. Astrophys. 589, A46 (2016).
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Published In
Science
Volume 368 • Issue 6490 • 1 May 2020
Pages: 518 - 521
History
Received: 13 June 2019
Accepted: 18 March 2020
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Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.
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http://dx.doi.org/10.13039/501100000781European Research Council: 715947
National Research Fundation of Korea: BK21
