![\"Astrometric](\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2026\/05\/Astrometric-exoplanet.png\")
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\n A demonstration of the limitations of the PSPT data processing pipeline, which did not process the limb uniformly with the rest of the Solar disc. The solid blue line is the stated extent of the solar disk in the original dataset, and the dashed red line is the extent to which the data has been cleaned. Note between the red and blue lines there exists a slight intensity increase \u2014 an example of the difference between the processed and unprocessed data separated by this boundary. \u2014 astro-ph.SR <\/p>\n
Astrometric monitoring of stars provides a promising method for discovery of low-mass planets around nearby Sun-like stars.<\/p>\n
The astronomical community has proposed several telescopes designed to perform high-precision astrometric observations. One limiting factor intrinsic to stars is the astrometric noise \u2013 or \u201cjitter\u201d \u2013 induced by surface stellar activity such as starspots and faculae. Despite previous estimates, the relative size of this signal has not been empirically measured from direct photometric observations.<\/p>\n
We analyse high-resolution images of the Sun to quantify the photometric centroid jitter across three narrow wavelength regions over nearly a decade, spanning high and low activity periods of the Solar cycle. We compare our findings to previous theoretical estimates.<\/p>\n
We scale this jitter to simulate how a Solar-twin would appear at various distances, establishing an astrometric noise floor below which detection is significantly complicated by stellar activity. We also introduce starspot simulations that augment our data. We find the typical astrometric jitter of the Sun at \ud835\udf06 = 607.2 \u00b1 0.25nm to be 0.342\ud835\udf07as pc, ranging between 0.058\ud835\udf07as pc and 1.294\ud835\udf07as pc for low and high activity periods, respectively.<\/p>\n
This is lower than the expected \u2248 3\ud835\udf07as astrometric signal that an Earth-like planet would produce around a Sun-like star, at 1 pc. Therefore, the astrometric noise floor imposed by intrinsic stellar activity sets a detection limit below one Earth but greater than Mars around Solar-analog stars, making instrument precision the limiting factor for Earth-like exoplanet searches.<\/p>\n
Conaire Deagan, Benjamin T. Montet, P. Tuthill, M. Ferraro, R. Lyu, E. Sheehan<\/p>\n
Comments: 20 pages, 14 Figures Astrobiology,<\/p>\n","protected":false},"excerpt":{"rendered":"A demonstration of the limitations of the PSPT data processing pipeline, which did not process the limb uniformly…\n","protected":false},"author":2,"featured_media":499711,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_share_on_mastodon":"0"},"categories":[77],"tags":[163975,217297,18,11511,203954,19,17,133,14001,17097,217298,184540,22916],"class_list":["post-499710","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-astro-ph-ep","tag-astrometric","tag-eire","tag-heliophysics","tag-https-astrobiology-com-2026-05-astronomy","tag-ie","tag-ireland","tag-science","tag-space-weather","tag-spectroscopy","tag-starspot","tag-stellar-cartography","tag-sun-like-star"],"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@ie\/116626470752044037","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/499710","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/comments?post=499710"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/499710\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media\/499711"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media?parent=499710"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/categories?post=499710"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/tags?post=499710"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Cite as: arXiv:2605.18953 [astro-ph.SR] (or arXiv:2605.18953v1 [astro-ph.SR] for this version)
https:\/\/doi.org\/10.48550\/arXiv.2605.18953<\/a>
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Submission history
From: Conaire Deagan
[v1] Mon, 18 May 2026 18:00:03 UTC (4,002 KB)
https:\/\/arxiv.org\/abs\/2605.18953<\/a><\/p>\n