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dc.contributor.authorFrance, Kevin
dc.contributor.authorParke Loyd, R. O.
dc.contributor.authorYoungblood, Allison
dc.contributor.authorBrown, Alexander
dc.contributor.authorSchneider, P. Christian
dc.contributor.authorHawley, Suzanne L.
dc.contributor.authorFroning, Cynthia S.
dc.contributor.authorLinsky, Jeffrey L.
dc.contributor.authorRoberge, Aki
dc.contributor.authorBuccino, Andrea P.
dc.contributor.authorDavenport, James R. A.
dc.contributor.authorFontenla, Juan M.
dc.contributor.authorKaltenegger, Lisa
dc.contributor.authorKowalski, Adam F.
dc.contributor.authorMauas, Pablo J. D.
dc.contributor.authorMiguel, Yamila
dc.contributor.authorRedfield, Seth
dc.contributor.authorRugheimer, Sarah
dc.contributor.authorTian, Feng
dc.contributor.authorVieytes, Mariela C.
dc.contributor.authorWalkowicz, Lucianne M.
dc.contributor.authorWeisenburger, Kolby L.
dc.date.accessioned2016-05-03T16:30:07Z
dc.date.available2016-05-03T16:30:07Z
dc.date.issued2016-03-22
dc.identifier.citationFrance , K , Parke Loyd , R O , Youngblood , A , Brown , A , Schneider , P C , Hawley , S L , Froning , C S , Linsky , J L , Roberge , A , Buccino , A P , Davenport , J R A , Fontenla , J M , Kaltenegger , L , Kowalski , A F , Mauas , P J D , Miguel , Y , Redfield , S , Rugheimer , S , Tian , F , Vieytes , M C , Walkowicz , L M & Weisenburger , K L 2016 , ' The MUSCLES Treasury Survey. I. Motivation and overview ' , Astrophysical Journal , vol. 820 , no. 2 , pp. 1-24 . https://doi.org/10.3847/0004-637X/820/2/89en
dc.identifier.issn0004-637X
dc.identifier.otherPURE: 242339487
dc.identifier.otherPURE UUID: aaf29856-5783-47a3-854c-b9264963640b
dc.identifier.otherBibtex: urn:aa70cdd537a0f52d26bcfd8281c99d72
dc.identifier.otherScopus: 84962909750
dc.identifier.otherORCID: /0000-0003-1620-7658/work/27162478
dc.identifier.otherWOS: 000373741300008
dc.identifier.urihttps://hdl.handle.net/10023/8719
dc.description.abstractGround- and space-based planet searches employing radial velocity techniques and transit photometry have detected thousands of planet-hosting stars in the Milky Way. With so many planets discovered, the next step toward identifying potentially habitable planets is atmospheric characterization. While the Sun–Earth system provides a good framework for understanding the atmospheric chemistry of Earth-like planets around solar-type stars, the observational and theoretical constraints on the atmospheres of rocky planets in the habitable zones (HZs) around low-mass stars (K and M dwarfs) are relatively few. The chemistry of these atmospheres is controlled by the shape and absolute flux of the stellar spectral energy distribution (SED), however, flux distributions of relatively inactive low-mass stars are poorly understood at present. To address this issue, we have executed a panchromatic (X-ray to mid-IR) study of the SEDs of 11 nearby planet-hosting stars, the Measurements of the Ultraviolet Spectral Characteristics of Low-mass Exoplanetary Systems (MUSCLES) Treasury Survey. The MUSCLES program consists visible observations from Hubble and ground-based observatories. Infrared and astrophysically inaccessible wavelengths (EUV and Lyα ) are reconstructed using stellar model spectra to fill in gaps in the observational data. In this overview and the companion papers describing the MUSCLES survey, we show that energetic radiation (X-ray and ultraviolet) is present from magnetically active stellar atmospheres at all times for stars as late as M6. The emission line luminosities of C iv and Mg ii are strongly correlated with band-integrated luminosities and we present empirical relations that can be used to estimate broadband FUV and XUV (≡X-ray + EUV) fluxes from individual stellar emission line measurements. We find that while the slope of the SED, FUV/NUV, increases by approximately two orders of magnitude form early K to late M dwarfs (≈0.01–1), the absolute FUV and XUV flux levels at their corresponding HZ distances are constant to within factors of a few, spanning the range 10–70 erg cm−2 s−1 in the HZ. Despite the lack of strong stellar activity indicators in their optical spectra, several of the M dwarfs in our sample show spectacular UV flare emission in their light curves. We present an example with flare/quiescent ultraviolet flux ratios of the order of 100:1 where the transition region energy output during the flare is comparable to the total quiescent luminosity of the star Eflare(UV) ∼ 0.3 L*Δt (Δt = 1 s). Finally, we interpret enhanced L(line)/LBol ratios for C iv and N v as tentative observational evidence for the interaction of planets with large planetary mass-to-orbital distance ratios (Mplan/aplan) with the transition regions of their host stars.
dc.format.extent24
dc.language.isoeng
dc.relation.ispartofAstrophysical Journalen
dc.rights© 2016. The American Astronomical Society. All rights reserved. This work is made available online in accordance with the publisher’s policies. This is the final published version of the work, which was originally published at: https://dx.doi.org/10.3847/0004-637X/2/89en
dc.subjectPlanetary systemsen
dc.subjectStars: activityen
dc.subjectStars: low-massen
dc.subjectQB Astronomyen
dc.subjectQC Physicsen
dc.subjectNDASen
dc.subject.lccQBen
dc.subject.lccQCen
dc.titleThe MUSCLES Treasury Survey. I. Motivation and overviewen
dc.typeJournal articleen
dc.description.versionPublisher PDFen
dc.contributor.institutionUniversity of St Andrews. Earth and Environmental Sciencesen
dc.identifier.doihttps://doi.org/10.3847/0004-637X/820/2/89
dc.description.statusPeer revieweden


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