EPIC 219388192 b - an inhabitant of the brown dwarf desert in the Ruprecht 147 open cluster

We report the discovery of EPIC 219388192 b, a transiting brown dwarf in a 5.3-day orbit around a member star of Ruprecht-147, the oldest nearby open cluster association, which was photometrically monitored by K2 during its Campaign 7. We combine the K2 time-series data with ground-based adaptive optics imaging and high resolution spectroscopy to rule out false positive scenarios and determine the main parameters of the system. EPIC 219388192 b has a radius of $R_\mathrm{b}$=$0.937\pm0.042$~$\mathrm{R_{Jup}}$ and mass of $M_\mathrm{b}$=$36.50\pm0.09$~$\mathrm{M_{Jup}}$, yielding a mean density of $59.0\pm8.1$~$\mathrm{g\,cm^{-3}}$. The host star is nearly a Solar twin with mass $M_\star$=$0.99\pm0.05$~$\mathrm{M_{\odot}}$, radius $R_\star$=$1.01\pm0.04$~$\mathrm{R_{\odot}}$, effective temperature $\mathrm{T_{eff}}$=$5850\pm85$~K and iron abundance [Fe/H]=$0.03\pm0.08$~dex. Its age, spectroscopic distance, and reddening are consistent with those of Ruprecht-147, corroborating its cluster membership. EPIC 219388192 b is the first brown dwarf with precise determinations of mass, radius and age, and serves as benchmark for evolutionary models in the sub-stellar regime.Comment: 13 pages, 11 figures, 4 tables, submitted to AAS Journal

The K2-ESPRINT Project II: Spectroscopic follow-up of three exoplanet systems from Campaign 1 of K2

We report on Doppler observations of three transiting planet candidates that were detected during Campaign 1 of the K2 mission. The Doppler observations were conducted with FIES, HARPS-N, and HARPS. We measure the mass of EPIC 201546283b, and provide constraints and upper limits for EPIC 201295312b and EPIC 201577035b. EPIC 201546283b is a warm Neptune orbiting its host star in 6.77 days and has a radius of 4.45_(-0.33)^(+0.33)R_⊕ and a mass of 29.1_(-7.4)^(+7.5)M_⊕, which leads to a mean density of 1.80_(-0.55)^(+0.70) cm^(-3). EPIC 201295312b is smaller than Neptune with an orbital period of 5.66 days, a radius of 2.75_(-0.22^)(0.24)R_⊕, and we constrain the mass to be below 12 M_⊕ at 95% confidence. We also find a long-term trend indicative of another body in the system. EPIC 201577035b, which was previously confirmed as the planet K2-10b, is smaller than Neptune, orbiting its host star in 19.3 days, with a radius of 3.84_(-0.34)^(+0.35)R_⊕. We determine its mass to be 27_(-16)^(+17)M_⊕, with a 95% confidence upper limit at 57M_⊕, and a mean density of 2.6_(-1.6)^(+2.1)g cm^(-3). These measurements join the relatively small collection of planets smaller than Neptune with measurements or constraints of the mean density. Our code for performing K2 photometry and detecting planetary transits is now publicly available

Doppler monitoring of five k2 transiting planetary systems

In an effort to measure the masses of planets discovered by the NASA K2 mission, we have conducted precise Doppler observations of five stars with transiting planets. We present the results of a joint analysis of these new data and previously published Doppler data. The first star, an M dwarf known as K2-3 or EPIC 201367065, has three transiting planets (“b,” with radius 2.1 R⊕; “c,” 1.7 R⊕; and “d,” 1.5 R⊕). Our analysis leads to the mass constraints: Mb = 8.1 -1.9 to +2.0 M⊕ and Mc < 4.2 M⊕ (95% confidence). The mass of planet d is poorly constrained because its orbital period is close to the stellar rotation period, making it difficult to disentangle the planetary signal from spurious Doppler shifts due to stellar activity. The second star, a G dwarf known as K2-19 or EPIC 201505350, has two planets (“b,” 7.7 R⊕; and “c,” 4.9 R⊕) in a 3:2 mean-motion resonance, as well as a shorter period planet (“d,” 1.1 R⊕). We find Mb = 28.5 -5.0 to +5.4 M⊕, Mc = 25.6 -7.1 to + 7.1 M⊕ and Md < 14.0M⊕ (95% conf.). The third star, a G dwarf known as K2-24 or EPIC 203771098, hosts two transiting planets (“b,” 5.7 R⊕; and “c,” 7.8 R⊕) with orbital periods in a nearly 2:1 ratio. We find Mb = 19.8 -4.4 to +4.5 M⊕ and Mc = 26.0 -6.1 to +5.8 M⊕. The fourth star, a G dwarf known as EPIC 204129699, hosts a hot Jupiter for which we measured the mass to be 1.857 +0.081 to -0.081 MJup. The fifth star, a G dwarf known as EPIC 205071984, contains three transiting planets (“b,” 5.4 R⊕; “c,” 3.5 R⊕; and “d,” 3.8 R⊕), the outer two of which have a nearly 2:1 period ratio. We find Mb = 21.1 -5.9 to +5.9 M⊕, Mc < 8.1 M⊕ (95% conf.) and Md < 35M⊕ (95% conf.)

Faisabilite de controle de production par camera video couplee a un micro-systeme informatique de prise de decision

CNRS AR 12150 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc

DOPPLER MONITORING OF FIVE K2 TRANSITING PLANETARY SYSTEMS

In an effort to measure the masses of planets discovered by the NASA K2 mission, we have conducted precise Doppler observations of five stars with transiting planets. We present the results of a joint analysis of these new data and previously published Doppler data. The first star, an M dwarf known as K2-3 or EPIC 201367065, has three transiting planets ("b," with radius "c," and "d," ). Our analysis leads to the mass constraints: M[subscript b] = 8.1[superscript =+2.0][subscript -1.9] M[subscript ⊕] And M[subscript c] < 4.2 M[subscript ⊕] (95% confidence). The mass of planet d is poorly constrained because its orbital period is close to the stellar rotation period, making it difficult to disentangle the planetary signal from spurious Doppler shifts due to stellar activity. The second star, a G dwarf known as K2-19 or EPIC 201505350, has two planets ("b," 7.7 R[subscript ⊕]; and "c," 4.9 R[subscript ⊕]) in a 3:2 mean-motion resonance, as well as a shorter-period planet ("d," 1.1 R[subscript ⊕]). We find M[subscript b] = 28.5[superscript +5.4][subscript -5.0]M[subscript ⊕], M[subscript c] = 25.6[superscript +7.1][subscript -7.1] and M[subscript d] < 14.0 M[subscript ⊕] (95% conf.). The third star, a G dwarf known as K2-24 or EPIC 203771098, hosts two transiting planets ("b," 5.7 R[subscript ⊕]; and "c," 7.8 R[subscript ⊕]) with orbital periods in a nearly 2:1 ratio. We find M[subscript b] = 19.8[superscript +4.5][subscript -4.4] and M[subscript c] = 26.0[superscript +5.8][subscript -6.1]. The fourth star, a G dwarf known as EPIC 204129699, hosts a hot Jupiter for which we measured the mass to be 1.857[superscript +0.081][subscript -0.081]M[subscript Jup]. The fifth star, a G dwarf known as EPIC 205071984, contains three transiting planets ("b," 5.4 R[subscript ⊕]; "c," 3.5 R[subscript ⊕]; and "d," 3.8 R[subscript ⊕]), the outer two of which have a nearly 2:1 period ratio. We find M[subscript b] = 21.1[superscript +5.9][subscript -5.9]M[subscript ⊕], M[subscript c] < 8.1 M[subscript ⊕] (95% conf.) and M[subscript d] < 35 M[subscript ⊕] (95% conf.)