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The First Dynamical Mass Measurement in the HR 8799 System
Dupuy, Trent J.; Brandt, Timothy D.; Brandt, G. Mirek +2 more
HR 8799 hosts four directly imaged giant planets, but none has a mass measured from first principles. We present the first dynamical mass measurement in this planetary system, finding that the innermost planet HR 8799 e has a mass of ${9.6}_{-1.8}^{+1.9}\,{M}_{\mathrm{Jup}}$ . This mass results from combining the well-characterized orbits of all f…
The McDonald Accelerating Stars Survey (MASS): Discovery of a Long-period Substellar Companion Orbiting the Old Solar Analog HD 47127
Cochran, William D.; Endl, Michael; Crepp, Justin R. +12 more
Brown dwarfs with well-determined ages, luminosities, and masses provide rare but valuable tests of low-temperature atmospheric and evolutionary models. We present the discovery and dynamical mass measurement of a substellar companion to HD 47127, an old (≈7-10 Gyr) G5 main-sequence star with a mass similar to the Sun. Radial velocities of the hos…
X-Ray AGB Stars in the 4XMM-DR9 Catalog: Further Evidence for Companions
Guerrero, M. A.; Ortiz, R.
Single AGB stars are not normally expected to be X-ray emitters due to the lack of a corona capable of powering a hot plasma. Therefore, the detection of X-ray emission in AGB stars by the ROSAT, Chandra, and XMM-Newton observatories has been interpreted as evidence for binarity. The number of X-ray-emitting AGB stars is, however, very small, and …
14 Her: A Likely Case of Planet-Planet Scattering
Gelino, Christopher R.; Faherty, Jacqueline K.; Bardalez Gagliuffi, Daniella C. +4 more
In this Letter, we measure the full orbital architecture of the two-planet system around the nearby K0 dwarf 14 Herculis. 14 Her (HD 145675, HIP 79248) is a middle-aged ( ${4.6}_{-1.3}^{+3.8}$ Gyr) K0 star with two eccentric giant planets identified in the literature from radial velocity (RV) variability and long-term trends. Using archival RV dat…