Skip to content

Research at St Andrews

The MUSCLES Treasury Survey. I. Motivation and overview

Research output: Contribution to journalArticle

Author(s)

Kevin France, R. O. Parke Loyd, Allison Youngblood, Alexander Brown, P. Christian Schneider, Suzanne L. Hawley, Cynthia S. Froning, Jeffrey L. Linsky, Aki Roberge, Andrea P. Buccino, James R. A. Davenport, Juan M. Fontenla, Lisa Kaltenegger, Adam F. Kowalski, Pablo J. D. Mauas, Yamila Miguel, Seth Redfield, Sarah Rugheimer, Feng Tian, Mariela C. Vieytes & 2 others Lucianne M. Walkowicz, Kolby L. Weisenburger

Abstract

Ground- 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 Ltt = 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.
Close

Details

Original languageEnglish
Pages (from-to)1-24
Number of pages24
JournalAstrophysical Journal
Volume820
Issue number2
DOIs
Publication statusPublished - 22 Mar 2016

    Research areas

  • Planetary systems, Stars: activity, Stars: low-mass

Discover related content
Find related publications, people, projects and more using interactive charts.

View graph of relations

Related by journal

  1. A cancellation nanoflare model for solar chromospheric and coronal heating. II. 2D theory and simulations

    Syntelis, P., Priest, E. R. & Chitta, L. P., 7 Feb 2019, In : Astrophysical Journal. 872, 1, 15 p., 32.

    Research output: Contribution to journalArticle

  2. Heating effects from driven transverse and Alfvén waves in coronal loops

    Guo, M., Van Doorsselaere, T., Karampelas, K., Li, B., Antolin, P. & De Moortel, I., 10 Jan 2019, In : Astrophysical Journal. 870, 2, 10 p., 55.

    Research output: Contribution to journalArticle

  3. The Sloan Digital Sky Survey Reverberation Mapping Project: systematic investigations of short-timescale CIV broad absorption line variability

    Hemler, Z. S., Grier, C. J., Brandt, W. N., Hall, P. B., Horne, K., Shen, Y., Trump, J. R., Schneider, D. P., Vivek, M., Bizyaev, D., Oravetz, A., Oravetz, D. & Pan, K., 6 Feb 2019, In : Astrophysical Journal. 872, 1, 21.

    Research output: Contribution to journalArticle

  4. The rotation-disk connection in young brown dwarfs: strong evidence for early rotational braking

    Moore, K., Scholz, A. & Jayawardhana, R., 20 Feb 2019, In : Astrophysical Journal. 872, 2, 20 p., 159.

    Research output: Contribution to journalArticle

  5. A comparison of simulated JWST observations derived from equilibrium and non-equilibrium chemistry models of giant exoplanets

    Blumenthal, S. D., Mandell, A. M., Hébrard, E., Batalha, N. E., Cubillos, P. E., Rugheimer, S. & Wakeford, H. R., 30 Jan 2018, In : Astrophysical Journal. 853, 2, 138.

    Research output: Contribution to journalArticle

Related by journal

  1. Astrophysical Journal (Journal)

    Carolin Villforth (Reviewer)
    2011 → …

    Activity: Publication peer-review and editorial work typesPeer review of manuscripts

  2. Astrophysical Journal (Journal)

    Christiane Helling (Reviewer)
    1 Jan 200631 Dec 2017

    Activity: Publication peer-review and editorial work typesPeer review of manuscripts

  3. Astrophysical Journal (Journal)

    Duncan Hendry Mackay (Editor)
    1997 → …

    Activity: Publication peer-review and editorial work typesEditor of research journal

  4. Astrophysical Journal (Journal)

    Alan William Hood (Editor)
    1980 → …

    Activity: Publication peer-review and editorial work typesEditor of research journal

ID: 242339487