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Duncan Wright

Publications and source records attributed to Duncan Wright.

39 records · Page 3Linked to original sources

KELT-14b and KELT-15b: An Independent Discovery of WASP-122b and a New Hot Jupiter

We report the discovery of KELT-14b and KELT-15b, two hot Jupiters from the KELT-South survey. KELT-14b, an independent discovery of the recently announced WASP-122b, is an inflated Jupiter mass planet that orbits a $\sim5.0^{+0.3}_{-0.7}$ Gyr, $V$ = 11.0, G2 star that is near the main sequence turnoff. The host star, KELT-14 (TYC 7638-981-1), has an inferred mass $M_{*}$=$1.18_{-0.07}^{+0.05}$$M_{\odot}$ and radius $R_{*}$=$1.37\pm{-0.08}$$R_{\odot}$, and has $T_{eff}$=$5802_{-92}^{+95}$K, $\log{g_*}$=$4.23_{-0.04}^{+0.05}$ and =$0.33\pm{0.09}$. The planet orbits with a period of $1.7100588 \pm 0.0000025$ days ($T_{0}$=2457091.02863$\pm$0.00047) and has a radius R$_{p}$=$1.52_{-0.11}^{+0.12}$$R_{J}$ and mass M$_{p}$=$1.196\pm0.072$$M_{J}$, and the eccentricity is consistent with zero. KELT-15b is another inflated Jupiter mass planet that orbits a $\sim$ $4.6^{+0.5}_{-0.4}$ Gyr, $V$ = 11.2, G0 star (TYC 8146-86-1) that is near the "blue hook" stage of evolution prior to the Hertzsprung gap, and has an inferred mass $M_{*}$=$1.181_{-0.050}^{+0.051}$$M_{\odot}$ and radius $R_{*}$=$1.48_{-0.04}^{+0.09}$$R_{\odot}$, and $T_{eff}$=$6003_{-52}^{+56}$K, $\log{g_*}$=$4.17_{-0.04}^{+0.02}$ and [Fe/H]=$0.05\pm0.03$. The planet orbits on a period of $3.329441 \pm 0.000016$ days ($T_{0}$ = 2457029.1663$\pm$0.0073) and has a radius R$_{p}$=$1.443_{-0.057}^{+0.11}$$R_{J}$ and mass M$_{p}$=$0.91_{-0.22}^{+0.21}$$M_{J}$ and an eccentricity consistent with zero. KELT-14b has the second largest expected emission signal in the K-band for known transiting planets brighter than $K<10.5$. Both KELT-14b and KELT-15b are predicted to have large enough emission signals that their secondary eclipses should be detectable using ground-based observatories.

astro-ph.EP↗

The Weihai Observatory search for close-in planets orbiting giant stars

Planets are known to orbit giant stars, yet there is a shortage of planets orbiting within ~0.5 AU (P<100 days). First-ascent giants have not expanded enough to engulf such planets, but tidal forces can bring planets to the surface of the star far beyond the stellar radius. So the question remains: are tidal forces strong enough in these stars to engulf all the missing planets? We describe a high-cadence observational program to obtain precise radial velocities of bright giants from Weihai Observatory of Shandong University. We present data on the planet host Beta Gem (HD 62509), confirming our ability to derive accurate and precise velocities; our data achieve an rms of 7.3 m/s about the Keplerian orbit fit. This planet-search programme currently receives ~100 nights per year, allowing us to aggressively pursue short-period planets to determine whether they are truly absent.

astro-ph.EP↗

Determination of the inclination of the multi-planet hosting star HR8799 using asteroseismology

Direct imaging of the HR8799 system was a major achievement in the study of exoplanets. HR8799 is a $γ$\,Doradus variable and asteroseismology can provide an independent constraint on the inclination. Using 650 high signal-to-noise, high resolution, full visual wavelength spectroscopic observations obtained over two weeks at Observatoire de Haute Provence (OHP) with the SOPHIE spectrograph we find that the main frequency in the radial velocity data is 1.9875 d$^{-1}$. This frequency corresponds to the main frequency as found in previous photometric observations. Using the FAMIAS software to identify the pulsation modes, we find this frequency is a prograde $\ell$=1 sectoral mode and obtain the constraint that inclination $i\gtrsim$40$^{\circ}$.

astro-ph.SR↗