Warm ice giant GJ 3470b - II. Revised planetary and stellar parameters from optical to near-infrared transit photometry

Biddle, L. I.; Pearson, K. A.; Crossfield, I. J. M.; Fulton, B. J.; Ciceri, S.; Eastman, J.; Barman, T.; Mann, A. W.; Henry, G. W.; Howard, A. W.; Williamson, M. H.; Sinukoff, E.; Dragomir, D.; Vican, L.; Mancini, L.; Southworth, J.; Greenberg, A.; Turner, J. D.; Thompson, R.; Taylor, B. W.; Levine, S. E.; Webber, M. W.

Abstract

It is important to explore the diversity of characteristics of low-mass, low-density planets to understand the nature and evolution of this class of planets. We present a homogeneous analysis of 12 new and 9 previously published broad-band photometric observations of the Uranus-sized extrasolar planet GJ 3470b, which belongs to the growing sample of sub-Jovian bodies orbiting M dwarfs. The consistency of our analysis explains some of the discrepancies between previously published results and provides updated constraints on the planetary parameters. Our data are also consistent with previous transit observations of this system. The physical properties of the transiting system can only be constrained as well as the host star is characterized, so we provide new spectroscopic measurements of GJ 3470 from 0.33 to 2.42 μm to aid our analysis. We find R* = 0.48 ± 0.04 R⊙, M* = 0.51 ± 0.06 M⊙, and Teff = 3652 ± 50K for GJ 3470, along with a rotation period of 20.70 ± 0.15 d and an R-band amplitude of 0.01 mag, which is small enough that current transit measurements should not be strongly affected by stellar variability. However, to report definitively whether stellar activity has a significant effect on the light curves, this requires future multiwavelength, multi-epoch studies of GJ 3470. We also present the most precise orbital ephemeris for this system: To = 2455983.70472 ± 0.00021BJDTDB, P = 3.336 6487

Citation

Biddle, L. I., Pearson, K. A., Crossfield, I. J. M., Fulton, B. J., Ciceri, S., Eastman, J., Barman, T., Mann, A. W., Henry, G. W., Howard, A. W., Williamson, M. H., Sinukoff, E., Dragomir, D., Vican, L., Mancini, L., Southworth, J., Greenberg, A., Turner, J. D., Thompson, R., Taylor, B. W., …Webber, M. W. (2014). Warm ice giant GJ 3470b - II. Revised planetary and stellar parameters from optical to near-infrared transit photometry. Monthly Notices of the Royal Astronomical Society, 443(2), 1810-1820. https://doi.org/10.1093/mnras/stu1199

• Journal Article Type: Article
• Acceptance Date: Jun 17, 2014
• Online Publication Date: Jul 25, 2014
• Publication Date: Jul 25, 2014
• Deposit Date: Jun 16, 2023
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 443
• Issue: 2
• Pages: 1810-1820
• DOI: https://doi.org/10.1093/mnras/stu1199
• Keywords: Space and Planetary Science, Astronomy and Astrophysics, techniques: photometric, techniques: spectroscopic, eclipses, planets and satellites: atmospheres, stars: individual: GJ 3470– infrared stars
• Public URL: https://keele-repository.worktribe.com/output/473715