bRing: An observatory dedicated to monitoring the β Pictoris b Hill sphere transit

¹ Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
e-mail: stuik@strw.leidenuniv.nl
² Department of Physics & Astronomy, University of Rochester, 500 Wilson Blvd., Rochester, NY 14627-0171, USA
³ South African Astronomical Observatory, Observatory Rd, Observatory Cape Town, 7700 Cape Town, South Africa
⁴ University of Cape Town, Rondebosch, 7700 Cape Town, South Africa
⁵ Jet Propulsion Laboratory, California Institute of Technology, M/S 321-100, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
⁶ Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611, Australia

Received: 31 July 2017
Accepted: 29 August 2017

Abstract

Aims. We describe the design and first light observations from the β Pictoris b Ring (“bRing”) project. The primary goal is to detect photometric variability from the young star β Pictoris due to circumplanetary material surrounding the directly imaged young extrasolar gas giant planet β Pictoris b.

Methods. Over a nine month period centred on September 2017, the Hill sphere of the planet will cross in front of the star, providing a unique opportunity to directly probe the circumplanetary environment of a directly imaged planet through photometric and spectroscopic variations. We have built and installed the first of two bRing monitoring stations (one in South Africa and the other in Australia) that will measure the flux of β Pictoris, with a photometric precision of 0.5% over 5 min. Each station uses two wide field cameras to cover the declination of the star at all elevations. Detection of photometric fluctuations will trigger spectroscopic observations with large aperture telescopes in order to determine the gas and dust composition in a system at the end of the planet-forming era.

Results. The first three months of operation demonstrate that bRing can obtain better than 0.5% photometry on β Pictoris in five minutes and is sensitive to nightly trends enabling the detection of any transiting material within the Hill sphere of the exoplanet.