[1107.5325] The HARPS search for southern extra-solar planets. XXXI. Magnetic activity cycles in solar-type stars: statistics and impact on precise radial velocities

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Magnetic activity cycles in solar-type stars: statistics and impact on precise radial velocities</title> <meta name="viewport" content="width=device-width, initial-scale=1"> <link rel="apple-touch-icon" sizes="180x180" href="/static/browse/0.3.4/images/icons/apple-touch-icon.png"> <link rel="icon" type="image/png" sizes="32x32" href="/static/browse/0.3.4/images/icons/favicon-32x32.png"> <link rel="icon" type="image/png" sizes="16x16" href="/static/browse/0.3.4/images/icons/favicon-16x16.png"> <link rel="manifest" href="/static/browse/0.3.4/images/icons/site.webmanifest"> <link rel="mask-icon" href="/static/browse/0.3.4/images/icons/safari-pinned-tab.svg" color="#5bbad5"> <meta name="msapplication-TileColor" content="#da532c"> <meta name="theme-color" content="#ffffff"> <link rel="stylesheet" type="text/css" media="screen" href="/static/browse/0.3.4/css/arXiv.css?v=20240822" /> <link rel="stylesheet" type="text/css" media="print" href="/static/browse/0.3.4/css/arXiv-print.css?v=20200611" /> <link rel="stylesheet" type="text/css" media="screen" href="/static/browse/0.3.4/css/browse_search.css" /> <script language="javascript" src="/static/browse/0.3.4/js/accordion.js" /></script> <link rel="canonical" href="https://arxiv.org/abs/1107.5325"/> <meta name="description" content="Abstract page for arXiv paper 1107.5325: The HARPS search for southern extra-solar planets. XXXI. Magnetic activity cycles in solar-type stars: statistics and impact on precise radial velocities"><meta property="og:type" content="website" /> <meta property="og:site_name" content="arXiv.org" /> <meta property="og:title" content="The HARPS search for southern extra-solar planets. XXXI. Magnetic activity cycles in solar-type stars: statistics and impact on precise radial velocities" /> <meta property="og:url" content="https://arxiv.org/abs/1107.5325v1" /> <meta property="og:image" content="/static/browse/0.3.4/images/arxiv-logo-fb.png" /> <meta property="og:image:secure_url" content="/static/browse/0.3.4/images/arxiv-logo-fb.png" /> <meta property="og:image:width" content="1200" /> <meta property="og:image:height" content="700" /> <meta property="og:image:alt" content="arXiv logo"/> <meta property="og:description" content="Context. Searching for extrasolar planets through radial velocity measurements relies on the stability of stellar photospheres. Aims. We aim at characterizing the statistical properties of magnetic activity cycles, and studying their impact on spectroscopic measurements such as radial velocities, line bisectors and line shapes. Methods. We use data from the HARPS high-precision planet-search sample comprising 304 FGK stars followed over about 7 years. We obtain high-precision Ca II H&K chromospheric activity measurements and convert them to R'HK indices using an updated calibration taking into account stellar metallicity. We study R'HK variability as a function of time and search for possible correlations with radial velocities and line shape parameters. Results. We classify stars according to the magnitude and timescale of the Ca II H&K variability, and identify activity cycles whenever possible. We find that 39+/-8% of old solar-type stars in the solar neighborhood do not show any activity cycles (or only very weak ones), while 61+/-8% do have one. Non-cycling stars are almost only found among G dwarfs and at mean activity levels log R'HK < -4.95. Magnetic cycle amplitude generally decreases with decreasing activity level. A significant fraction of stars exhibit small variations in radial velocities and line shape parameters that are correlated with activity cycles. The sensitivity of radial velocities to magnetic cycles increases towards hotter stars, while late K dwarfs are almost insensitive. Conclusions. Activity cycles do induce long-period, low-amplitude radial velocity variations, at levels up to ~25 m/s. Caution is therefore mandatory when searching for long-period exoplanets. However, these effects can be corrected to high precision by detrending the radial velocity data using simultaneous measurements of Ca II H&K flux and line shape parameters. 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We aim at characterizing the statistical properties of..."/> <meta name="twitter:image" content="https://static.arxiv.org/icons/twitter/arxiv-logo-twitter-square.png"/> <meta name="twitter:image:alt" content="arXiv logo"/> <link rel="stylesheet" media="screen" type="text/css" href="/static/browse/0.3.4/css/tooltip.css"/><link rel="stylesheet" media="screen" type="text/css" href="https://static.arxiv.org/js/bibex-dev/bibex.css?20200709"/> <script src="/static/browse/0.3.4/js/mathjaxToggle.min.js" type="text/javascript"></script> <script src="//code.jquery.com/jquery-latest.min.js" type="text/javascript"></script> <script src="//cdn.jsdelivr.net/npm/js-cookie@2/src/js.cookie.min.js" type="text/javascript"></script> <script src="//cdn.jsdelivr.net/npm/dompurify@2.3.5/dist/purify.min.js"></script> <script src="/static/browse/0.3.4/js/toggle-labs.js?20241022" type="text/javascript"></script> <script src="/static/browse/0.3.4/js/cite.js" type="text/javascript"></script><meta name="citation_title" content="The HARPS search for southern extra-solar planets. XXXI. Magnetic activity cycles in solar-type stars: statistics and impact on precise radial velocities" /><meta name="citation_author" content="Lovis, C." /><meta name="citation_author" content="Dumusque, X." /><meta name="citation_author" content="Santos, N. C." /><meta name="citation_author" content="Bouchy, F." /><meta name="citation_author" content="Mayor, M." /><meta name="citation_author" content="Pepe, F." /><meta name="citation_author" content="Queloz, D." /><meta name="citation_author" content="S茅gransan, D." /><meta name="citation_author" content="Udry, S." /><meta name="citation_date" content="2011/07/26" /><meta name="citation_online_date" content="2011/07/26" /><meta name="citation_pdf_url" content="http://arxiv.org/pdf/1107.5325" /><meta name="citation_arxiv_id" content="1107.5325" /><meta name="citation_abstract" content="Context. Searching for extrasolar planets through radial velocity measurements relies on the stability of stellar photospheres. Aims. We aim at characterizing the statistical properties of magnetic activity cycles, and studying their impact on spectroscopic measurements such as radial velocities, line bisectors and line shapes. Methods. We use data from the HARPS high-precision planet-search sample comprising 304 FGK stars followed over about 7 years. We obtain high-precision Ca II H&K chromospheric activity measurements and convert them to R'HK indices using an updated calibration taking into account stellar metallicity. We study R'HK variability as a function of time and search for possible correlations with radial velocities and line shape parameters. Results. We classify stars according to the magnitude and timescale of the Ca II H&K variability, and identify activity cycles whenever possible. We find that 39+/-8% of old solar-type stars in the solar neighborhood do not show any activity cycles (or only very weak ones), while 61+/-8% do have one. Non-cycling stars are almost only found among G dwarfs and at mean activity levels log R'HK < -4.95. Magnetic cycle amplitude generally decreases with decreasing activity level. A significant fraction of stars exhibit small variations in radial velocities and line shape parameters that are correlated with activity cycles. The sensitivity of radial velocities to magnetic cycles increases towards hotter stars, while late K dwarfs are almost insensitive. Conclusions. Activity cycles do induce long-period, low-amplitude radial velocity variations, at levels up to ~25 m/s. Caution is therefore mandatory when searching for long-period exoplanets. However, these effects can be corrected to high precision by detrending the radial velocity data using simultaneous measurements of Ca II H&K flux and line shape parameters. 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XXXI. Magnetic activity cycles in solar-type stars: statistics and impact on precise radial velocities</h1> <div class="authors"><span class="descriptor">Authors:</span><a href="https://arxiv.org/search/astro-ph?searchtype=author&query=Lovis,+C" rel="nofollow">C. Lovis</a>, <a href="https://arxiv.org/search/astro-ph?searchtype=author&query=Dumusque,+X" rel="nofollow">X. Dumusque</a>, <a href="https://arxiv.org/search/astro-ph?searchtype=author&query=Santos,+N" rel="nofollow">N.C. Santos</a>, <a href="https://arxiv.org/search/astro-ph?searchtype=author&query=Bouchy,+F" rel="nofollow">F. Bouchy</a>, <a href="https://arxiv.org/search/astro-ph?searchtype=author&query=Mayor,+M" rel="nofollow">M. Mayor</a>, <a href="https://arxiv.org/search/astro-ph?searchtype=author&query=Pepe,+F" rel="nofollow">F. Pepe</a>, <a href="https://arxiv.org/search/astro-ph?searchtype=author&query=Queloz,+D" rel="nofollow">D. Queloz</a>, <a href="https://arxiv.org/search/astro-ph?searchtype=author&query=S%C3%A9gransan,+D" rel="nofollow">D. S茅gransan</a>, <a href="https://arxiv.org/search/astro-ph?searchtype=author&query=Udry,+S" rel="nofollow">S. Udry</a></div> <div id="download-button-info" hidden>View a PDF of the paper titled The HARPS search for southern extra-solar planets. XXXI. Magnetic activity cycles in solar-type stars: statistics and impact on precise radial velocities, by C. Lovis and 8 other authors</div> <a class="mobile-submission-download" href="/pdf/1107.5325">View PDF</a> <blockquote class="abstract mathjax"> <span class="descriptor">Abstract:</span>Context. Searching for extrasolar planets through radial velocity measurements relies on the stability of stellar photospheres. Aims. We aim at characterizing the statistical properties of magnetic activity cycles, and studying their impact on spectroscopic measurements such as radial velocities, line bisectors and line shapes. Methods. We use data from the HARPS high-precision planet-search sample comprising 304 FGK stars followed over about 7 years. We obtain high-precision Ca II H&K chromospheric activity measurements and convert them to R'HK indices using an updated calibration taking into account stellar metallicity. We study R'HK variability as a function of time and search for possible correlations with radial velocities and line shape parameters. Results. We classify stars according to the magnitude and timescale of the Ca II H&K variability, and identify activity cycles whenever possible. We find that 39+/-8% of old solar-type stars in the solar neighborhood do not show any activity cycles (or only very weak ones), while 61+/-8% do have one. Non-cycling stars are almost only found among G dwarfs and at mean activity levels log R'HK < -4.95. Magnetic cycle amplitude generally decreases with decreasing activity level. A significant fraction of stars exhibit small variations in radial velocities and line shape parameters that are correlated with activity cycles. The sensitivity of radial velocities to magnetic cycles increases towards hotter stars, while late K dwarfs are almost insensitive. Conclusions. Activity cycles do induce long-period, low-amplitude radial velocity variations, at levels up to ~25 m/s. Caution is therefore mandatory when searching for long-period exoplanets. However, these effects can be corrected to high precision by detrending the radial velocity data using simultaneous measurements of Ca II H&K flux and line shape parameters. (Abridged) </blockquote>  <div class="metatable"> <table summary="Additional metadata"> <tr> <td class="tablecell label">Comments:</td> <td class="tablecell comments mathjax">25 pages, 19 figures, submitted to A&A</td> </tr> <tr> <td class="tablecell label">Subjects:</td> <td class="tablecell subjects"> <span class="primary-subject">Solar and Stellar Astrophysics (astro-ph.SR)</span>; Earth and Planetary Astrophysics (astro-ph.EP)</td> </tr><tr> <td class="tablecell label">Cite as:</td> <td class="tablecell arxivid"><span class="arxivid"><a href="https://arxiv.org/abs/1107.5325">arXiv:1107.5325</a> [astro-ph.SR]</span></td> </tr> <tr> <td class="tablecell label"> </td> <td class="tablecell arxividv">(or <span class="arxivid"> <a href="https://arxiv.org/abs/1107.5325v1">arXiv:1107.5325v1</a> [astro-ph.SR]</span> for this version) </td> </tr> <tr> <td class="tablecell label"> </td> <td class="tablecell arxivdoi"> <a href="https://doi.org/10.48550/arXiv.1107.5325" id="arxiv-doi-link">https://doi.org/10.48550/arXiv.1107.5325</a><div class="button-and-tooltip"> <button class="more-info" aria-describedby="more-info-desc-1"> <svg height="15" role="presentation" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><path fill="currentColor" d="M256 8C119.043 8 8 119.083 8 256c0 136.997 111.043 248 248 248s248-111.003 248-248C504 119.083 392.957 8 256 8zm0 110c23.196 0 42 18.804 42 42s-18.804 42-42 42-42-18.804-42-42 18.804-42 42-42zm56 254c0 6.627-5.373 12-12 12h-88c-6.627 0-12-5.373-12-12v-24c0-6.627 5.373-12 12-12h12v-64h-12c-6.627 0-12-5.373-12-12v-24c0-6.627 5.373-12 12-12h64c6.627 0 12 5.373 12 12v100h12c6.627 0 12 5.373 12 12v24z" class=""></path></svg> <span class="visually-hidden">Focus to learn more</span> </button>  <div role="tooltip" id="more-info-desc-1"> <span class="left-corner"></span> arXiv-issued DOI via DataCite</div> </div> </td> </tr></table> </div> </div> </div> <div class="submission-history"> <h2>Submission history</h2> From: Christophe Lovis [<a href="/show-email/e48ad2f1/1107.5325" rel="nofollow">view email</a>] <br/> <strong>[v1]</strong> Tue, 26 Jul 2011 20:36:33 UTC (350 KB)<br/> </div> </div>  <div class="extra-services"> <div class="full-text"> <a name="other"></a> <span class="descriptor">Full-text links:</span> <h2>Access Paper:</h2> <ul> <div id="download-button-info" hidden> View a PDF of the paper titled The HARPS search for southern extra-solar planets. 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[1107.5325] The HARPS search for southern extra-solar planets. XXXI. Magnetic activity cycles in solar-type stars: statistics and impact on precise radial velocities