Direct Imaging of a Cold Jovian Exoplanet in Orbit Around the Sun-Like Star Gj 504

Abstract

Direct Imaging of a Cold Jovian Exoplanet in Orbit around the Sun-like Star GJ 504Kuzuhara, M.; et al., [Unknown]; Thalmann, C.D. General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Download date: 13 May 2018The Astrophysical Journal, 774:11 (18pp) ABSTRACT Several exoplanets have recently been imaged at wide separations of >10 AU from their parent stars. These span a limited range of ages (<50 Myr) and atmospheric properties, with temperatures of 800-1800 K and very red colors (J − H > 0.5 mag), implying thick cloud covers. Furthermore, substantial model uncertainties exist at these young ages due to the unknown initial conditions at formation, which can lead to an order of magnitude of uncertainty in the modeled planet mass. Here, we report the direct-imaging discovery of a Jovian exoplanet around the Sun-like star GJ 504, detected as part of the SEEDS survey. The system is older than all other known directly imaged planets; as a result, its estimated mass remains in the planetary regime independent of uncertainties related to choices of initial conditions in the exoplanet modeling. Using the most common exoplanet cooling model, and given the system age of 160 +350 −60 Myr, GJ 504b has an estimated mass of 4 +4.5 −1.0 Jupiter masses, among the lowest of directly imaged planets. Its projected separation of 43.5 AU exceeds the typical outer boundary of ∼30 AU predicted for the core accretion mechanism. GJ 504b is also significantly cooler (510 +30 −20 K) and has a bluer color (J − H = −0.23 mag) than previously imaged exoplanets, suggesting a largely cloud-free atmosphere accessible to spectroscopic characterization. Thus, it has the potential of providing novel insights into the origins of giant planets as well as their atmospheric properties.

The VLT/NaCo large program to probe the occurrence of exoplanets and brown dwarfs in wide orbits

“…the introduction of angular differential imaging, Marois et al 2006) allowed the detection of the first objects that were likely formed in protoplanetary disks, such as the four-planet system orbiting HR 8799 (Marois et al 2008(Marois et al , 2010 and the giant planet orbiting at 8 AU from the well known star-disk system β Pic ). In the last year, several additional discoveries of directly-imaged planets have been reported (Rameau et al 2013;Kuzuhara et al 2013;Currie et al 2014).…”

The LEECH Exoplanet Imaging Survey. Further constraints on the planet architecture of the HR 8799 system

“…Optimized observing strategy and data analysis are required to overcome the high contrasts ( 10 4 ) and the small separations (a few tenths of an arcsecond) between a star and a planet. The development of adaptive optics systems, coronagraphic devices, and differential imaging techniques in the past fifteen years allowed detection of planetary-mass objects in favorable situations: young and nearby host star, large orbital separation, and/or low star/planet mass ratio (e.g., Chauvin et al 2005;Marois et al 2008Marois et al , 2010bLagrange et al 2010;Lafrenière et al 2010;Kuzuhara et al 2013;Rameau et al 2013;Bailey et al 2014). A new generation of instruments dedicated to the search and characterization of young exoplanets down to the Jupiter mass has started operations (Tamura & SEEDS Team 2010;Hinkley et al 2011;Close et al 2013;Skemer et al 2014a;Macintosh et al 2014;Beuzit et al 2012).…”

Performance of the VLT Planet Finder SPHERE

“…Moreover, this technique allows us to obtain photometric, spectroscopic, and astrometric measurements of the detected companions, and for this reason it is a fundamental technique to study the atmosphere of the known objects, their mass-luminosity function and their orbits (see, e.g, Rameau et al 2013a;Kuzuhara et al 2013;Esposito et al 2013;Currie et al 2013) . However, direct detection of extrasolar planets is challenging for two reasons: (1) the large luminosity contrast with respect to the star, which is of the order of 10 −6 for giant young planets with high intrinsic luminosity, and 10 −8 -10 −9 for old planets seen in reflected and intrinsic light; and (2) the small separation between the star and the planet, of the order of a few tenths of arcsec for planets at few AUs around stars at a distance up to 100 pc from the Sun.…”