Abstract
We present the first ground-based CCD (lambda <1 mu m) image of an extrasolar planet. Using the Magellan Adaptive Optics system's VisAO camera, we detected the extrasolar giant planet beta Pictoris b in Y-short (Y-S, 0.985 mu m), at a separation of 0.470 +/- 0 ''.010 and a contrast of (1.63 +/- 0.49) Chi 10(-5). This detection has a signal-to-noise ratio of 4.1 with an empirically estimated upper limit on false alarm probability of 1.0%. We also present new photometry from the Gemini Near-Infrared Coronagraphic Imager instrument on the Gemini South telescope, in CH4S, 1% (1.58 mu m), K-S (2.18 mu m), and K-cont (2.27 mu m). A thorough analysis of our photometry combined with previous measurements yields an estimated near-IR spectral type of L2.5 +/- 1.5, consistent with previous estimates. We estimate log(L-bol/L-circle dot) = -3.86 +/- 0.04, which is consistent with prior estimates for beta Pic b and with field early-L brown dwarfs (BDs). This yields a hot-start mass estimate of 11.9 +/- 0.7 M-Jup for an age of 21 +/- 4Myr, with an upper limit below the deuterium burning mass. Our L-bol-based hot-start estimate for temperature is T-eff = 1643 +/- 32 K (not including model-dependent uncertainty). Due to the large corresponding model-derived radius of R = 1.43 +/- 0.02 R-Jup, this T-eff is similar to 250 K cooler than would be expected for a field L2.5 BD. Other young, low-gravity (large-radius), ultracool dwarfs and directly imaged EGPs also have lower effective temperatures than are implied by their spectral types. However, such objects tend to be anomalously red in the near-IR compared to field BDs. In contrast, beta Pic b has near-IR colors more typical of an early-L dwarf despite its lower inferred temperature.
Original language | English |
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Article number | 32 |
Number of pages | 22 |
Journal | Astrophysical Journal |
Volume | 786 |
Issue number | 1 |
DOIs | |
Publication status | Published - 1 May 2014 |
Keywords / Materials (for Non-textual outputs)
- brown dwarfs
- instrumentation: adaptive optics
- planetary systems
- planets and satellites: detection
- planets and satellites: individual (beta Pictoris b)
- stars: individual (beta Pictoris)
- PLANET-FINDING CAMPAIGN
- LOW-MASS STARS
- EXTRASOLAR GIANT PLANETS
- PICTORIS MOVING GROUP
- ORION TRAPEZIUM CLUSTER
- DIRECTLY IMAGED PLANET
- L DWARF COMPANION
- ORBITING HR 8799
- EDGE-ON DISK
- MID-T DWARFS