A Transiting Jupiter Analog (1603.00042v1)

Abstract: Decadal-long radial velocity surveys have recently started to discover analogs to the most influential planet of our solar system, Jupiter. Detecting and characterizing these worlds is expected to shape our understanding of our uniqueness in the cosmos. Despite the great successes of recent transit surveys, Jupiter analogs represent a terra incognita, owing to the strong intrinsic bias of this method against long orbital periods. We here report on the first validated transiting Jupiter analog, Kepler-167e (KOI-490.02), discovered using Kepler archival photometry orbiting the K4-dwarf KIC-3239945. With a radius of $(0.91\pm0.02)$ $R_{\mathrm{Jup}}$, a low orbital eccentricity ($0.06_{-0.04}^{+0.10}$) and an equilibrium temperature of $(131\pm3)$ K, Kepler-167e bears many of the basic haLLMarks of Jupiter. Kepler-167e is accompanied by three Super-Earths on compact orbits, which we also validate, leaving a large cavity of transiting worlds around the habitable-zone. With two transits and continuous photometric coverage, we are able to uniquely and precisely measure the orbital period of this post snow-line planet ($1071.2323\pm0.0006$ d), paving the way for follow-up of this $K=11.8$ mag target.

• The paper validates Kepler-167e as a transiting Jupiter analog using archival Kepler photometry to measure its 1071-day orbit and low eccentricity.
• The study employs multibody asterodensity profiling and Bayesian model selection to robustly confirm the planet's characteristics and rule out false positives.
• The findings reveal a unique system architecture with inner Super-Earths coexisting with an external gas giant, highlighting potential for atmospheric characterization in the infrared.

Analysis of "A Transiting Jupiter Analog"

The paper "A Transiting Jupiter Analog" presented by Kipping et al. offers an insightful paper of the validated transiting Jupiter analog, Kepler-167e, demonstrating significant advancements in the detection and characterization of long-period exoplanets using transit photometry. This paper utilizes archival photometry data from the Kepler mission to identify and validate the planetary nature of Kepler-167e, a compelling Jupiter analog orbiting the K4-dwarf, KIC-3239945.

Summary and Scientific Contributions

This research highlights the discovery of Kepler-167e, which possesses a radius of $0.91 \pm 0.02$, low orbital eccentricity ($0.06_{-0.04}^{+0.10}$), and a remarkably low equilibrium temperature ($131 \pm 3$ K), reflecting essential similarities to Jupiter. These parameters are consistent with a planet that resides beyond the snow line, a characteristic region in planetary systems where volatile compounds condensate into solid ice grains, fostering the formation of gas giants like Jupiter. The planet orbits the host star with an extended orbital period of $1071.2323 \pm 0.0006$ days, making it distinctive among transiting exoplanets due to such a large orbit.

Kepler-167e is part of a system inclusive of three other Super-Earths, which are notable for their compact orbits. The coexistence of these inner planets with an external Jupiter analog provides a unique perspective on system architecture, resembling a configuration of compact inner planetary bodies and a full-scale gas giant occupying external orbits—potentially analogous to a hybrid arrangement of the solar system's terrestrial planets and Jupiter.

Methodological Insights

The paper utilizes multibody asterodensity profiling (MAP), allowing for the determination of eccentricities purely from transit light curves, a significant methodological innovation. This approach considers the mean stellar density derived from transit analyses of multiple planets orbiting the same star, sidestepping the reliance on stellar models alone. The team implements Bayesian model selection to reinforce the validation process, offering robust probabilistic considerations of the planetary scenario versus alternative explanations like brown dwarfs or background binaries.

Implications and Future Prospects

The successful identification of Kepler-167e underscores the potential of transit photometry to explore long-period exoplanets, which are inherently challenging to detect due to low transit probabilities and lengthy orbital intervals. The existence of such planets opens a pathway to interrogating the prevalence of Jupiter-like bodies beyond the classical detection methods like radial velocities.

Practically, Kepler-167e offers opportunities for atmospheric characterization, albeit challenging due to the star's faintness in optical wavelengths. However, its deeper infrared brightness could render the planet accessible to near- and mid-infrared observational campaigns, potentially illuminating atmospheric compositions analogous to Jupiter.

Looking forward, these findings suggest that compact planetary systems identified by transit surveys might hide additional long-period giants akin to Kepler-167e, warranting further investigations through advanced transit surveys and precise radial velocity follow-ups.

Ultimately, this research presents a significant stride in confirming transiting Jupiter analogs, enhancing our understanding of planetary formation and system evolution, and opening new avenues for comprehensive atmospheric studies as telescope technologies evolve.