arXiv subjects

Cristián Cortés

Publications and source records attributed to Cristián Cortés.

4 recordsLinked to original sources

arXiv2018

K2-287b: an Eccentric Warm Saturn transiting a G-dwarf

We report the discovery of K2-287b, a Saturn mass planet orbiting a G-dwarf with a period of $P \approx 15$ days. First uncovered as a candidate using K2 campaign 15 data, follow-up photometry and spectroscopy were used to determine a mass of $M_P = 0.317 \pm 0.026$ $M_J$, radius $R_P = 0.833 \pm 0.013$ $R_J$, period $P = 14.893291 \pm 0.000025$ days and eccentricity $e = 0.476 \pm 0.026$. The host star is a metal-rich $V=11.410 \pm 0.129$ mag G dwarf for which we estimate a mass $M_* = 1.056$ $M_\odot$, radius $R_* = 1.07 \pm 0.01$ $R_\odot$, metallicity [Fe/H] = $0.20 \pm 0.05$ and $T_{eff} = 5673 \pm 75$ K. This warm eccentric planet with a time-averaged equilibrium temperature of $T_{eq} \approx 800$ K adds to the small sample of giant planets orbiting nearby stars whose structure is not expected to be affected by stellar irradiation. Follow-up studies on the K2-287 system could help in constraining theories of migration of planets in close-in orbits.

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arXiv2018

EPIC 201498078b: A low density Super Neptune on an eccentric orbit

We report the discovery of EPIC 201498078b, which was first identified as a planetary candidate from Kepler K2 photometry of Campaign 14, and whose planetary nature and orbital parameters were then confirmed with precision radial velocities. EPIC 201498078b is half as massive as Saturn ($\rm M_P$=$0.179 \pm 0.021$ $\rm M_J$), and has a radius of $\rm R_P$=$0.840 \pm 0.011$ $\rm R_J$, which translates into a bulk density of $ \rm ρ_P$=$0.37 \pm 0.05$ g cm$^{-3}$. EPIC 201498078b transits its slightly evolved G-type host star ($\rm M_{\star}$=$1.105 \pm 0.019$ $\rm M_{\odot}$, $\rm R_P$=$1.669 \pm 0.022$ $\rm R_{\odot}$) every $11.63364 \pm 0.00010$ days and presents a significantly eccentric orbit ($e=0.420 \pm 0.034$). We estimate a relatively short circularization timescale of 1.8 Gyr for the planet, but given the advanced age of the system we expect the planet to be engulfed by its evolving host star in $\sim 1$ Gyr before the orbit circularizes. The low density of the planet coupled to the brightness of the host star ($J=9.4$) makes this system one of the best candidates known to date in the super-Neptune regime for atmospheric characterization via transmission spectroscopy, and to further study the transition region between ice and gas giant planets.

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arXiv2017

K2-113b: A dense hot-Jupiter transiting a solar analogue

We present the discovery of K2-113b, a dense hot-Jupiter discovered using photometry from Campaign 8 of the Kepler-2 (K2) mission and high-resolution spectroscopic follow up obtained with the FEROS spectrograph. The planet orbits a $V=13.68$ solar analogue in a $P=5.81760^{+0.00003}_{-0.00003}$ day orbit, has a radius of $0.93^{+0.10}_{-0.07}R_J$ and a mass of $1.29^{+0.13}_{-0.14}M_J$. With a density of $1.97^{+0.60}_{-0.53}$ gr/cm$^3$, the planet is among the densest systems known having masses below 2 $M_J$ and $T_{eq} > 1000$, and is just above the temperature limit at which inflation mechanisms are believed to start being important. Based on its mass and radius, we estimate that K2-113b should have a heavy element content on the order of $\sim$ 110 $M_{\oplus}$ or greater.

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arXiv2016

An independent discovery of two hot Jupiters from the K2 mission

We report the discovery of two hot Jupiters using photometry from Campaigns 4 and 5 of the two-wheeled Kepler (K2) mission. K2-30b has a mass of $ 0.65 \pm 0.14 M_J$, a radius of $1.070 \pm 0.018 R_J$ and transits its G dwarf ($T_{eff} = 5675 \pm 50$ K), slightly metal rich ([Fe/H]$=+0.06\pm0.04$ dex) host star in a 4.1 days circular orbit. K2-34b has a mass of $ 1.63 \pm 0.12 M_J$, a radius of $1.38 \pm 0.014 R_J$ and has an orbital period of 3.0 days in which it orbits a late F dwarf ($T_{eff} = 6149 \pm 55$ K) solar metallicity star. Both planets were validated probabilistically and confirmed via precision radial velocity (RV) measurements. They have physical and orbital properties similar to the ones of the already uncovered population of hot Jupiters and are well-suited candidates for further orbital and atmospheric characterization via detailed follow-up observations. Given that the discovery of both systems was recently reported by other groups we take the opportunity of refining the planetary parameters by including the RVs obtained by these independent studies in our global analysis.

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