CaltechAUTHORS
Published March 2019 | Version Accepted Version + Published
Journal Article Open

Bright Opportunities for Atmospheric Characterization of Small Planets: Masses and Radii of K2-3 b, c, d and GJ3470 b from Radial Velocity Measurements and Spitzer Transits

Creators

  • 1. ROR icon University of California, Santa Cruz
  • 2. ROR icon Massachusetts Institute of Technology
  • 3. ROR icon University of Toledo
  • 4. ROR icon University of Tokyo
  • 5. ROR icon University of Montreal
  • 6. ROR icon Tennessee State University
  • 7. ROR icon University of North Carolina at Chapel Hill
  • 8. ROR icon California Institute of Technology
  • 9. ROR icon University of California, Berkeley
  • 10. ROR icon University of Hawaii at Manoa
  • 11. ROR icon Institut de Planétologie et d'Astrophysique de Grenoble
  • 12. ROR icon Goddard Space Flight Center
  • 13. ROR icon Jet Propulsion Lab
  • 14. ROR icon Moorpark College
  • 15. ROR icon California State University, Northridge
  • 16. ROR icon University of Geneva
  • 17. ROR icon Instituto de Astrofísica de Canarias
  • 18. ROR icon University of La Laguna
  • 19. ROR icon University of Porto
  • 20. ROR icon University of Barcelona

Abstract

We report improved masses, radii, and densities for four planets in two bright M-dwarf systems, K2-3 and GJ3470, derived from a combination of new radial velocity and transit observations. Supplementing K2 photometry with follow-up Spitzer transit observations refined the transit ephemerides of K2-3 b, c, and d by over a factor of 10. We analyze ground-based photometry from the Evryscope and Fairborn Observatory to determine the characteristic stellar activity timescales for our Gaussian Process fit, including the stellar rotation period and activity region decay timescale. The stellar rotation signals for both stars are evident in the radial velocity data and is included in our fit using a Gaussian process trained on the photometry. We find the masses of K2-3 b, K2-3 c, and GJ3470 b to be 6.48^(+0.99)_(-0.93), 2.14^(+1.08)_(-1.04), and 12.58^(+1.31)_(-1.28) M⊕, respectively. K2-3 d was not significantly detected and has a 3σ upper limit of 2.80 M⊕. These two systems are training cases for future TESS systems; due to the low planet densities (ρ < 3.7 g cm^(−3)) and bright host stars (K < 9 mag), they are among the best candidates for transmission spectroscopy in order to characterize the atmospheric compositions of small planets.

Additional Information

© 2019 The American Astronomical Society. Received 2018 March 13; revised 2018 November 21; accepted 2018 December 6; published 2019 February 5. M.R.K. acknowledges support from the NSF Graduate Research Fellowship, grant No. DGE 1339067. I.J.M.C. acknowledges support from NASA through K2GO grant 80NSSC18K0308 and from NSF through grant AST-1824644. G.W.H. acknowledges long-term support from NASA, NSF, Tennessee State University, and the State of Tennessee through its Centers of Excellence program. O.F. acknowledges funding support by the grant MDM-2014-0369 of the ICCUB (Unidad de Excelencia "María de Maeztu"). This work is based [in part] on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. This research has made use of the Exoplanet Follow-up Observing Program (ExoFOP), which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. Facilities: Keck:I - KECK I Telescope, Spitzer - Spitzer Space Telescope satellite, TNG - Telescopio Nazionale Galileo.

Attached Files

Published - Kosiarek_2019_AJ_157_97.pdf

Accepted Version - 1812.08241.pdf

Files

1812.08241.pdf

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Additional details

Identifiers

Eprint ID
92458
Resolver ID
CaltechAUTHORS:20190124-122603169

Related works

Describes
https://arxiv.org/abs/1812.08241 (URL)

Funding

NSF Graduate Research Fellowship
DGE-1339067
NASA
80NSSC18K0308
NSF
AST-1824644
Tennessee State University
State of Tennessee Centers of Excellence program
Ministerio de Economía, Industria y Competitividad (MINECO)
MDM-2014-0369
NASA/JPL/Caltech

Dates

Created
2019-01-25
Created from EPrint's datestamp field
Updated
2021-11-16
Created from EPrint's last_modified field

Caltech Custom Metadata

Caltech groups
Infrared Processing and Analysis Center (IPAC) , Astronomy Department , Division of Geological and Planetary Sciences (GPS)