First Results From VLT NACO Apodizing Phase Plate: 4-micron Images of the Exoplanet beta Pictoris b

TL;DR

This paper reports the first scientific results using the VLT/NACO Apodizing Phase Plate coronagraph to image the exoplanet beta Pictoris b at 4 microns, confirming its position and properties with high contrast imaging.

Contribution

First application of the VLT/NACO APP coronagraph for direct imaging of an exoplanet, demonstrating its effectiveness in high contrast, high resolution observations of beta Pictoris b.

Findings

Detected beta Pictoris b at 4.05 micron with good positional agreement

Estimated the planet's mass as 7-10 Jupiter masses for a 12 Myr old system

Suggested an effective temperature of approximately 1700 K for the planet

Abstract

Direct imaging of exoplanets requires both high contrast and high spatial resolution. Here, we present the first scientific results obtained with the newly commissioned Apodizing Phase Plate coronagraph (APP) on VLT/NACO. We detected the exoplanet beta Pictoris b in the narrow band filter centered at 4.05 micron (NB4.05). The position angle (209.13 +- 2.12 deg) and the projected separation to its host star (0."354 +- 0".012, i.e., 6.8 +- 0.2 AU at a distance of 19.3 pc) are in good agreement with the recently presented data from Lagrange et al. (2010). Comparing the observed NB4.05 magnitude of 11.20 +- 0.23 mag to theoretical atmospheric models we find a best fit with a 7-10 M_Jupiter object for an age of 12 Myr, again in agreement with previous estimates. Combining our results with published L' photometry we can compare the planet's [L' - NB4.05] color to that of cool field dwarfs of higher surface gravity suggesting an effective temperature of ~1700 K. The best fit theoretical model predicts an effective temperature of ~1470 K, but this difference is not significant given our photometric uncertainties. Our results demonstrate the potential of NACO/APP for future planet searches and provides independent confirmation as well as complementary data for beta Pictoris b.