WASP-16b: A New Jupiter-Like Planet Transiting a Southern Solar Analog

in Astrophysical Journal (2009), 703

We report the discovery from WASP-South of a new Jupiter-like extrasolar planet, WASP-16b, which transits its solar analog host star every 3.12 days. Analysis of the transit photometry and radial velocity ... [more ▼]

We report the discovery from WASP-South of a new Jupiter-like extrasolar planet, WASP-16b, which transits its solar analog host star every 3.12 days. Analysis of the transit photometry and radial velocity spectroscopic data leads to a planet with R [SUB]p[/SUB] = 1.008 ± 0.071 R [SUB]Jup[/SUB] and M [SUB]p[/SUB] = 0.855 ± 0.059 M [SUB]Jup[/SUB], orbiting a host star with R [SUB]*[/SUB] = 0.946 ± 0.054 R [SUB]sun[/SUB] and M [SUB]*[/SUB] = 1.022 ± 0.101 M [SUB]sun[/SUB]. Comparison of the high resolution stellar spectrum with synthetic spectra and stellar evolution models indicates the host star is a near-solar metallicity ([Fe/H] =0.01 ± 0.10) solar analog (T [SUB]eff[/SUB] = 5700 ± 150 K and log g = 4.5 ± 0.2) of intermediate age (tau = 2.3[SUP]+5.8[/SUP] [SUB]--2.2[/SUB] Gyr). [less ▲]

Discovery and characterization of WASP-6b, an inflated sub-Jupiter mass planet transiting a solar-type star

in Astronomy and Astrophysics (2009), 501

We report the discovery of WASP-6b, an inflated sub-Jupiter mass planet transiting every 3.3610060[SUP]+ 0.0000022 [/SUP][SUB]- 0.0000035 [/SUB] days a mildly metal-poor solar-type star of magnitude V ... [more ▼]

We report the discovery of WASP-6b, an inflated sub-Jupiter mass planet transiting every 3.3610060[SUP]+ 0.0000022 [/SUP][SUB]- 0.0000035 [/SUB] days a mildly metal-poor solar-type star of magnitude V = 11.9. A combined analysis of the WASP photometry, high-precision followup transit photometry and radial velocities yield a planetary mass M[SUB]p[/SUB] = 0.503[SUP]+0.019[/SUP][SUB]-0.038[/SUB] M[SUB]J[/SUB] and radius R[SUB]p[/SUB] = 1.224[SUP]+0.051[/SUP][SUB]-0.052[/SUB] R_J, resulting in a density rho[SUB]p[/SUB] = 0.27 ± 0.05 rho_J. The mass and radius for the host star are M_ast = 0.88[SUP]+0.05[/SUP][SUB]-0.08[/SUB] M_o and R_ast = 0.870[SUP]+0.025[/SUP][SUB]-0.036[/SUB] R_o. The non-zero orbital eccentricity e = 0.054^+0.018[SUB]-0.015[/SUB] that we measure suggests that the planet underwent a massive tidal heating 1 Gyr ago that could have contributed to its inflated radius. High-precision radial velocities obtained during a transit allow us to measure a sky-projected angle between the stellar spin and orbital axis beta = 11[SUP]+14[/SUP][SUB]-18[/SUB] deg. In addition to similar published measurements, this result favors a dominant migration mechanism based on tidal interactions with a protoplanetary disk. Based on data collected with the HARPS spectrograph at ESO La Silla Observatory in the programs 082.C-0040(E) and 082.C-0608. The photometric time-series and radial velocities (Tables 4, 5) used in this work are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/501/785 [less ▲]

Improved parameters for the transiting hot Jupiters WASP-4b and WASP-5b

in Astronomy and Astrophysics (2009), 496

The gaseous giant planets WASP-4b and WASP-5b are transiting 12-magnitude solar-type stars in the Southern hemisphere. The aim of the present work is to refine the parameters of these systems using high ... [more ▼]

The gaseous giant planets WASP-4b and WASP-5b are transiting 12-magnitude solar-type stars in the Southern hemisphere. The aim of the present work is to refine the parameters of these systems using high cadence VLT/FORS2 z-band transit photometry and high-resolution VLT/UVES spectroscopy. For WASP-4, the new estimates for the planet radius and mass from a combined analysis of our VLT data with previously published transit photometry and radial velocities are R[SUB]p[/SUB] = 1.30[SUP]+0.05[/SUP][SUB]-0.04[/SUB] R[SUB]J[/SUB] and M[SUB]p[/SUB] = 1.21[SUP]+0.13[/SUP][SUB]-0.08[/SUB] M_J, resulting in a density rho[SUB]p[/SUB] = 0.55[SUP]+0.04[/SUP][SUB]-0.02[/SUB] rho_J. The radius and mass for the host star are R_* = 0.87[SUP]+0.04[/SUP][SUB]-0.03[/SUB] R_o and M_* = 0.85[SUP]+0.11[/SUP][SUB]-0.07[/SUB] M_o. Our ground-based photometry reaches 550 ppm at time sampling of ~50 s. Nevertheless, we also report the presence of an instrumental effect on the VLT that degraded our photometry for the WASP-5 observations. This effect could be a major problem for similar programs. Our new estimates for the parameters of the WASP-5 system are R[SUB]p[/SUB] = 1.09 ± 0.07 R_J, M[SUB]p[/SUB] = 1.58[SUP]+0.13[/SUP][SUB]-0.10[/SUB] M_J, rho[SUB]p[/SUB] = 1.23 [SUP]+0.26[/SUP][SUB]-0.16[/SUB] rho_J, R_* = 1.03[SUP]+0.06[/SUP][SUB]-0.07[/SUB] R_o, and M_* = 0.96[SUP]+0.13[/SUP][SUB]-0.09[/SUB] M_o. The measured size of WASP-5b agrees well with the basic models of irradiated planets, while WASP-4b is clearly an ``anomalously'' large planet. Based on data collected with the FORS2 imager at the VLT-UT4 telescope and with the UVES spectrograph at the VLT-UT2 telescope (Paranal Observatory, ESO, Chile) in the programme 280.C-5003. [less ▲]

The Masses and Radii of HD186753B and TYC7096-222-1B: The First M-dwarfs known to Eclipse A-type Stars

in Astronomy and Astrophysics (2009)

We present observations of two new single-lined eclipsing binaries, both consisting of an Am star and an M-dwarf, discovered by the Wide Angle Search for Planets transit photometry survey. Using WASP ... [more ▼]

We present observations of two new single-lined eclipsing binaries, both consisting of an Am star and an M-dwarf, discovered by the Wide Angle Search for Planets transit photometry survey. Using WASP photometry and spectroscopic measurements we find that HD186753B has an orbital period of $P=1.9194$ days, a mass of $M=0.24\pm0.02 M_{\odot}$ and radius of $R=0.31^{+0.06}_{-0.06} R_{\odot}$; and that TCY7096-222-1B has an orbital period of $P=8.9582$ days, a mass of between 0.29 and 0.54 $M_{\odot}$ depending on eccentricity and radius of $R=0.263^{+0.02}_{-0.07} R_{\odot}$. We find that the Am stars have relatively low rotational velocities that closely match the orbital velocities of the M-dwarfs, suggesting that they have been "spun-down" by the M-dwarfs. [less ▲]

WASP-4b: A 12th Magnitude Transiting Hot Jupiter in the Southern Hemisphere

in Astrophysical Journal (2008), 675

We report the discovery of WASP-4b, a large transiting gas-giant planet with an orbital period of 1.34 days. This is the first planet to be discovered by the SuperWASP-South observatory and CORALIE ... [more ▼]

We report the discovery of WASP-4b, a large transiting gas-giant planet with an orbital period of 1.34 days. This is the first planet to be discovered by the SuperWASP-South observatory and CORALIE collaboration and the first planet orbiting a star brighter than 16th magnitude to be discovered in the southern hemisphere. A simultaneous fit to high-quality light curves and precision radial velocity measurements leads to a planetary mass of 1.22[SUP]+0.09[/SUP][SUB]-0.08[/SUB] M[SUB]Jup[/SUB] and a planetary radius of 1.42[SUP]+0.07[/SUP][SUB]-0.04[/SUB] R[SUB]Jup[/SUB]. The host star is USNO-B1.0 0479-0948995, a G7 V star of visual magnitude 12.5. As a result of the short orbital period, the predicted surface temperature of the planet is 1761 K, making it an ideal candidate for detections of the secondary eclipse at infrared wavelengths. [less ▲]