We use high dynamic range, high-resolution L-band spectroscopy to measure the radial velocity variations of the hot Jupiter in the τ Boötis planetary system. The detection of an exoplanet by the shift in the stellar spectrum alone provides a measure of the planet's minimum mass, with the true mass degenerate with the unknown orbital inclination. Treating the τ Boo system as a high flux ratio double-lined spectroscopic binary permits the direct measurement of the planet's true mass as well as its atmospheric properties. After removing telluric absorption and cross-correlating with a model planetary spectrum dominated by water opacity, we measure a 6-σ detection of the planet at K p = 111 ± 5 km/s, with a 1-σ upper limit on the spectroscopic flux ratio of 10 −4 . This radial velocity leads to a planetary orbital inclination of i = 45 +3 −4 degrees and a mass of M P = 5.90 +0.35 −0.20 M Jup . We report the first detection of water vapor in the atmosphere of a non-transiting hot Jupiter, τ Boo b.

The James Webb Space Telescope (JWST) Early Release Observations (EROs) is a set of public outreach products created to mark the end of commissioning and the beginning of science operations for JWST. Colloquially known as the “Webb First Images and Spectra,” these products were intended to demonstrate to the worldwide public that JWST is ready for science, and is capable of producing spectacular results. The package was released on 2022 July 12 and included images and spectra of the galaxy cluster SMACS J0723.3-7327 and distant lensed galaxies, the interacting galaxy group Stephan’s Quintet, NGC 3324 in the Carina star-forming complex, the Southern Ring planetary nebula NGC 3132, and the transiting hot Jupiter WASP-96b. This paper describes the ERO technical design, observations, and scientific processing of data underlying the colorful outreach products.

This paper characterizes the actual science performance of the James Webb Space Telescope (JWST), as determined from the six month commissioning period. We summarize the performance of the spacecraft, telescope, science instruments, and ground system, with an emphasis on differences from pre-launch expectations. Commissioning has made clear that JWST is fully capable of achieving the discoveries for which it was built. Moreover, almost across the board, the science performance of JWST is better than expected; in most cases, JWST will go deeper faster than expected. The telescope and instrument suite have demonstrated the sensitivity, stability, image quality, and spectral range that are necessary to transform our understanding of the cosmos through observations spanning from near-earth asteroids to the most distant galaxies.

The Upsilon Andromedae system was the first multi-planet system discovered orbiting a main-sequence star. We describe the detection of water vapor in the atmosphere of the innermost non-transiting gas giant upsAndb by treating the star-planet system as a spectroscopic binary with high-resolution, ground-based spectroscopy. We resolve the signal of the planet's motion and break the mass-inclination degeneracy for this non-transiting planet via deep combined flux observations of the star and the planet. In total, seven epochs of Keck NIRSPEC L band observations, three epochs of Keck NIRSPEC short-wavelength K band observations, and three epochs of Keck NIRSPEC long wavelength K band observations of the upsAndsystem were obtained. We perform a multi-epoch cross-correlation of the full data set with an atmospheric model. We measure the radial projection of the Keplerian velocity (K P =55 ± 9kms M J ), and orbital inclination (i b 24°± 4°), and determine that the planet's opacity structure is dominated by water vapor at the probed wavelengths. Dynamical simulations of the planets in the upsAndsystem with these orbital elements for upsAndb show that stable, long-term (100Myr) orbital configurations exist. These measurements will inform future studies of the stability and evolution of the upsAndsystem, as well as the atmospheric structure and composition of the hot Jupiter.

We describe the detection of water vapor in the atmosphere of the transiting hot Jupiter KELT-2Ab by treating the star-planet system as a spectroscopic binary with high-resolution, ground-based spectroscopy. We resolve the signal of the planet's motion with deep combined flux observations of the star and the planet. In total, six epochs of Keck NIRSPEC L-band observations were obtained, and the full data set was subjected to a cross correlation analysis with a grid of self-consistent atmospheric models. We measure a radial projection of the Keplerian velocity, K P , of 148 ± 7 km s −1 , consistent with transit measurements, and detect water vapor at 3.8σ. We combine NIRSPEC L-band data with Spitzer IRAC secondary eclipse data to further probe the metallicity and carbon-to-oxygen ratio of KELT-2Ab's atmosphere. While the NIRSPEC analysis provides few extra constraints on the Spitzer data, it does provide roughly the same constraints on metallicity and carbon-to-oxygen ratio. This bodes well for future investigations of the atmospheres of non-transiting hot Jupiters.