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Radial Velocities from the N2K Project: Six New Cold Gas Giant Planets Orbiting HD 55696, HD 98736, HD 148164, HD 203473, and HD 211810
Howard, Andrew W.; Fischer, Debra A.; Ment, Kristo +2 more
The N2K planet search program was designed to exploit the planet-metallicity correlation by searching for gas giant planets orbiting metal-rich stars. Here, we present the radial velocity measurements for 378 N2K target stars that were observed with the HIRES spectrograph at Keck Observatory between 2004 and 2017. With this data set, we announce t…
Community Targets of JWST’s Early Release Science Program: Evaluation of WASP-63b
Deming, Drake; Madhusudhan, Nikku; Burrows, Adam +21 more
We present observations of WASP-63b by the Hubble Space Telescope (HST) as part of “A Preparatory Program to Identify the Single Best Transiting Exoplanet for James Webb Space Telescope (JWST) Early Release Science (ERS).” WASP-63b is one of the community targets under consideration for the JWST ERS program. We present a spectrum derived from a si…
Dynamics and Formation of the Near-resonant K2-24 System: Insights from Transit-timing Variations and Radial Velocities
Deming, Drake; Gorjian, Varoujan; Fulton, Benjamin J. +8 more
While planets between the size of Uranus and Saturn are absent within the solar system, the star K2-24 hosts two such planets, K2-24b and c, with radii equal to 5.4 {R}\oplus and 7.5 {R}\oplus , respectively. The two planets have orbital periods of 20.9 days and 42.4 days, residing only 1% outside the nominal 2:1 mean-motion…
The Taurus Boundary of Stellar/Substellar (TBOSS) Survey. II. Disk Masses from ALMA Continuum Observations
Pinte, C.; Ménard, F.; van der Plas, G. +9 more
We report 885 µm ALMA continuum flux densities for 24 Taurus members spanning the stellar/substellar boundary with spectral types from M4 to M7.75. Of the 24 systems, 22 are detected at levels ranging from 1.0 to 55.7 mJy. The two nondetections are transition disks, though other transition disks in the sample are detected. Converting ALMA co…
Shedding Light on the Isolation of Luminous Blue Variables
Drout, Maria R.; Aadland, Erin; Massey, Philip +1 more
In the standard view of massive star evolution, luminous blue variables (LBVs) are transitional objects between the most massive O-type stars and Wolf-Rayet (WR) stars. With short lifetimes, these stars should all be found near one another. A recent study of LBVs in the Large Magellanic Cloud (LMC) found instead that LBVs are considerably more iso…
KELT-21b: A Hot Jupiter Transiting the Rapidly Rotating Metal-poor Late-A Primary of a Likely Hierarchical Triple System
Cargile, Phillip A.; Bieryla, Allyson; Latham, David W. +65 more
We present the discovery of KELT-21b, a hot Jupiter transiting the V = 10.5 A8V star HD 332124. The planet has an orbital period of P = 3.6127647 ± 0.0000033 days and a radius of {1.586}-0.040+0.039 {R}{{J}}. We set an upper limit on the planetary mass of {M}P< 3.91 {M}{{J}} at 3σ confidenc…
Plausible Home Stars of the Interstellar Object ‘Oumuamua Found in Gaia DR2
Buie, Marc W.; Bailer-Jones, Coryn A. L.; Chakrabarti, Sukanya +5 more
The first detected interstellar object, ‘Oumuamua, which passed within 0.25 au of the Sun on 2017 September 9, was presumably ejected from a stellar system. We use its newly determined non-Keplerian trajectory together with the reconstructed Galactic orbits of 7 million stars from Gaia DR2 to identify past close encounters. Such an “encounter” cou…
More Rapidly Rotating PMS M Dwarfs with Light Curves Suggestive of Orbiting Clouds of Material
Cody, Ann Marie; Rebull, Luisa; Hillenbrand, Lynne A. +8 more
In a previous paper, using data from K2 Campaign 2, we identified 11 very low mass members of the ρ Oph and Upper Scorpius star-forming region as having periodic photometric variability and phased light curves showing multiple scallops or undulations. All of the stars with the “scallop-shell” light curve morphology are mid-to-late M dwarfs without…
Cloud Atlas: Discovery of Rotational Spectral Modulations in a Low-mass, L-type Brown Dwarf Companion to a Star
Schneider, Glenn; Apai, Dániel; Burgasser, Adam J. +11 more
Observations of rotational modulations of brown dwarfs and giant exoplanets allow the characterization of condensate cloud properties. As of now, rotational spectral modulations have only been seen in three L-type brown dwarfs. We report here the discovery of rotational spectral modulations in LP261-75B, an L6-type intermediate surface gravity com…
A Significant Overluminosity in the Transiting Brown Dwarf CWW 89Ab
Burrows, Adam; Davenport, James R. A.; Montet, Benjamin T. +3 more
We observed eclipses of the transiting brown dwarf CWW 89Ab at 3.6 and 4.5 µm using Spitzer/IRAC. The CWW 89 binary system is a member of the 3.0 ± 0.25 Gyr old open cluster Ruprecht 147 and is composed of a Sun-like primary and an early M-dwarf secondary separated by a projected distance of 25 au. CWW 89Ab has a radius of 0.937 ± 0.042 {R}<…