Forecasting the Impact of Stellar Activity on Transiting Exoplanet Spectra

Robert T. Zellem, Mark R. Swain, Gael Roudier, Evgenya Shkolnik, Michelle J. Creech-Eakman, David R. Ciardi, Michael Line, Aishwarya R. Iyer, Geoffrey Bryden, Joe Llama, Kristen A. Fahy

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Exoplanet host star activity, in the form of unocculted starspots or faculae, alters the observed transmission and emission spectra of the exoplanet. This effect can be exacerbated when combining data from different epochs if the stellar photosphere varies between observations due to activity. Here, we present a method to characterize and correct for relative changes due to stellar activity by exploiting multi-epoch (≥2 visits/transits) observations to place them in a consistent reference frame. Using measurements from portions of the planet's orbit where negligible planet transmission or emission can be assumed, we determine changes to the stellar spectral amplitude. With the analytical methods described here, we predict the impact of stellar variability on transit observations. Supplementing these forecasts with Kepler-measured stellar variabilities for F-, G-, K-, and M-dwarfs, and predicted transit precisions by the James Webb Space Telescope's (JWST) NIRISS, NIRCam, and MIRI, we conclude that stellar activity does not impact infrared transiting exoplanet observations of most presently known or predicted TESS targets by current or near-future platforms, such as JWST, as activity-induced spectral changes are below the measurement precision.

Original languageEnglish (US)
Article number27
JournalAstrophysical Journal
Volume844
Issue number1
DOIs
StatePublished - Jul 20 2017

Fingerprint

stellar activity
extrasolar planets
forecasting
planet
transit
James Webb Space Telescope
planets
analytical method
time measurement
starspots
faculae
photosphere
emission spectra
platforms
orbits
stars
forecast
effect
method

Keywords

  • methods: analytical
  • planets and satellites: atmospheres
  • planets and satellites: detection
  • stars: activity
  • starspots

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Zellem, R. T., Swain, M. R., Roudier, G., Shkolnik, E., Creech-Eakman, M. J., Ciardi, D. R., ... Fahy, K. A. (2017). Forecasting the Impact of Stellar Activity on Transiting Exoplanet Spectra. Astrophysical Journal, 844(1), [27]. https://doi.org/10.3847/1538-4357/aa79f5

Forecasting the Impact of Stellar Activity on Transiting Exoplanet Spectra. / Zellem, Robert T.; Swain, Mark R.; Roudier, Gael; Shkolnik, Evgenya; Creech-Eakman, Michelle J.; Ciardi, David R.; Line, Michael; Iyer, Aishwarya R.; Bryden, Geoffrey; Llama, Joe; Fahy, Kristen A.

In: Astrophysical Journal, Vol. 844, No. 1, 27, 20.07.2017.

Research output: Contribution to journalArticle

Zellem, RT, Swain, MR, Roudier, G, Shkolnik, E, Creech-Eakman, MJ, Ciardi, DR, Line, M, Iyer, AR, Bryden, G, Llama, J & Fahy, KA 2017, 'Forecasting the Impact of Stellar Activity on Transiting Exoplanet Spectra', Astrophysical Journal, vol. 844, no. 1, 27. https://doi.org/10.3847/1538-4357/aa79f5
Zellem, Robert T. ; Swain, Mark R. ; Roudier, Gael ; Shkolnik, Evgenya ; Creech-Eakman, Michelle J. ; Ciardi, David R. ; Line, Michael ; Iyer, Aishwarya R. ; Bryden, Geoffrey ; Llama, Joe ; Fahy, Kristen A. / Forecasting the Impact of Stellar Activity on Transiting Exoplanet Spectra. In: Astrophysical Journal. 2017 ; Vol. 844, No. 1.
@article{0c57a15730614d35901e65340416cca9,
title = "Forecasting the Impact of Stellar Activity on Transiting Exoplanet Spectra",
abstract = "Exoplanet host star activity, in the form of unocculted starspots or faculae, alters the observed transmission and emission spectra of the exoplanet. This effect can be exacerbated when combining data from different epochs if the stellar photosphere varies between observations due to activity. Here, we present a method to characterize and correct for relative changes due to stellar activity by exploiting multi-epoch (≥2 visits/transits) observations to place them in a consistent reference frame. Using measurements from portions of the planet's orbit where negligible planet transmission or emission can be assumed, we determine changes to the stellar spectral amplitude. With the analytical methods described here, we predict the impact of stellar variability on transit observations. Supplementing these forecasts with Kepler-measured stellar variabilities for F-, G-, K-, and M-dwarfs, and predicted transit precisions by the James Webb Space Telescope's (JWST) NIRISS, NIRCam, and MIRI, we conclude that stellar activity does not impact infrared transiting exoplanet observations of most presently known or predicted TESS targets by current or near-future platforms, such as JWST, as activity-induced spectral changes are below the measurement precision.",
keywords = "methods: analytical, planets and satellites: atmospheres, planets and satellites: detection, stars: activity, starspots",
author = "Zellem, {Robert T.} and Swain, {Mark R.} and Gael Roudier and Evgenya Shkolnik and Creech-Eakman, {Michelle J.} and Ciardi, {David R.} and Michael Line and Iyer, {Aishwarya R.} and Geoffrey Bryden and Joe Llama and Fahy, {Kristen A.}",
year = "2017",
month = "7",
day = "20",
doi = "10.3847/1538-4357/aa79f5",
language = "English (US)",
volume = "844",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "1",

}

TY - JOUR

T1 - Forecasting the Impact of Stellar Activity on Transiting Exoplanet Spectra

AU - Zellem, Robert T.

AU - Swain, Mark R.

AU - Roudier, Gael

AU - Shkolnik, Evgenya

AU - Creech-Eakman, Michelle J.

AU - Ciardi, David R.

AU - Line, Michael

AU - Iyer, Aishwarya R.

AU - Bryden, Geoffrey

AU - Llama, Joe

AU - Fahy, Kristen A.

PY - 2017/7/20

Y1 - 2017/7/20

N2 - Exoplanet host star activity, in the form of unocculted starspots or faculae, alters the observed transmission and emission spectra of the exoplanet. This effect can be exacerbated when combining data from different epochs if the stellar photosphere varies between observations due to activity. Here, we present a method to characterize and correct for relative changes due to stellar activity by exploiting multi-epoch (≥2 visits/transits) observations to place them in a consistent reference frame. Using measurements from portions of the planet's orbit where negligible planet transmission or emission can be assumed, we determine changes to the stellar spectral amplitude. With the analytical methods described here, we predict the impact of stellar variability on transit observations. Supplementing these forecasts with Kepler-measured stellar variabilities for F-, G-, K-, and M-dwarfs, and predicted transit precisions by the James Webb Space Telescope's (JWST) NIRISS, NIRCam, and MIRI, we conclude that stellar activity does not impact infrared transiting exoplanet observations of most presently known or predicted TESS targets by current or near-future platforms, such as JWST, as activity-induced spectral changes are below the measurement precision.

AB - Exoplanet host star activity, in the form of unocculted starspots or faculae, alters the observed transmission and emission spectra of the exoplanet. This effect can be exacerbated when combining data from different epochs if the stellar photosphere varies between observations due to activity. Here, we present a method to characterize and correct for relative changes due to stellar activity by exploiting multi-epoch (≥2 visits/transits) observations to place them in a consistent reference frame. Using measurements from portions of the planet's orbit where negligible planet transmission or emission can be assumed, we determine changes to the stellar spectral amplitude. With the analytical methods described here, we predict the impact of stellar variability on transit observations. Supplementing these forecasts with Kepler-measured stellar variabilities for F-, G-, K-, and M-dwarfs, and predicted transit precisions by the James Webb Space Telescope's (JWST) NIRISS, NIRCam, and MIRI, we conclude that stellar activity does not impact infrared transiting exoplanet observations of most presently known or predicted TESS targets by current or near-future platforms, such as JWST, as activity-induced spectral changes are below the measurement precision.

KW - methods: analytical

KW - planets and satellites: atmospheres

KW - planets and satellites: detection

KW - stars: activity

KW - starspots

UR - http://www.scopus.com/inward/record.url?scp=85026357529&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85026357529&partnerID=8YFLogxK

U2 - 10.3847/1538-4357/aa79f5

DO - 10.3847/1538-4357/aa79f5

M3 - Article

VL - 844

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1

M1 - 27

ER -