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Variability in a Young, L/T Transition Planetary-Mass Object

Research output: Contribution to journalArticle

  • Beth A. Biller
  • Johanna Vos
  • Mariangela Bonavita
  • Esther Buenzli
  • Claire Baxter
  • Ian J. M. Crossfield
  • Katelyn Allers
  • Michael C. Liu
  • Mickaël Bonnefoy
  • Niall Deacon
  • Wolfgang Brandner
  • Joshua E. Schlieder
  • Trent Dupuy
  • Taisiya Kopytova
  • Elena Manjavacas
  • France Allard
  • Derek Homeier
  • Thomas Henning

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Original languageEnglish
JournalAstrophysical Journal
Publication statusPublished - 30 Oct 2015


As part of our ongoing NTT SoFI survey for variability in young free-floating planets and low mass brown dwarfs, we detect significant variability in the young, free-floating planetary mass object PSO J318.5-22, likely due to rotational modulation of inhomogeneous cloud cover. A member of the 23$\pm$3 Myr $\beta$ Pic moving group, PSO J318.5-22 has T$_\mathrm{eff}$ = 1160$^{+30}_{-40}$ K and a mass estimate of 8.3$\pm$0.5 M$_{Jup}$ for a 23$\pm$3 Myr age. PSO J318.5-22 is intermediate in mass between 51 Eri b and $\beta$ Pic b, the two known exoplanet companions in the $\beta$ Pic moving group. With variability amplitudes from 7-10$\%$ in J$_{S}$ at two separate epochs over 3-5 hour observations, we constrain the rotational period of this object to $>$5 hours. In K$_{S}$, we marginally detect a variability trend of up to 3$\%$ over a 3 hour observation. This is the first detection of weather on an extrasolar planetary mass object. Among L dwarfs surveyed at high-photometric precision ($

    Research areas

  • astro-ph.EP

ID: 57878155