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Direct-imaging Discovery of a Substellar Companion Orbiting the Accelerating Variable Star HIP 39017
DOI: 10.3847/1538-3881/ad3077 Bibcode: 2024AJ....167..205T

Salama, Maïssa; Currie, Thayne; Lewis, Briley L. +23 more

We present the direct-imaging discovery of a substellar companion (a massive planet or low-mass brown dwarf) to the young, γ Doradus (γ Dor)-type variable star HIP 39017 (HD 65526). The companion's SCExAO/CHARIS JHK (1.1–2.4 µm) spectrum and Keck/NIRC2 $L^{\prime} $ photometry indicate that it is an L/T transition object. A comparison of the…

2024 The Astronomical Journal
Gaia Hipparcos 8
Observations with the Differential Speckle Survey Instrument. XI. First Year of Observations from Apache Point Observatory
DOI: 10.3847/1538-3881/ad1ff6 Bibcode: 2024AJ....167..117D

Majewski, Steven R.; Henry, Todd J.; Chanover, Nancy J. +18 more

The Differential Speckle Survey Instrument (DSSI) was relocated to the Astrophysical Research Consortium 3.5 m telescope at Apache Point Observatory (APO) in early 2022. Here we present results from the first year of observations along with an updated instrument description for DSSI at APO, including a detailed description of a new internal slit m…

2024 The Astronomical Journal
Gaia Hipparcos 7
Dynamical Architectures of S-type Transiting Planets in Binaries. I. Target Selection Using Hipparcos and Gaia Proper Motion Anomalies
DOI: 10.3847/1538-3881/ad1189 Bibcode: 2024AJ....167...89Z

Tan, Thiam-Guan; Huber, Daniel; Weiss, Lauren M. +16 more

The effect of stellar multiplicity on planetary architecture and orbital dynamics provides an important context for exoplanet demographics. We present a volume-limited catalog of up to 300 pc of 66 stars hosting planets and planet candidates from Kepler, K2, and TESS with significant Hipparcos-Gaia proper motion anomalies, which indicates the pres…

2024 The Astronomical Journal
Gaia Hipparcos eHST 6
VLTI/GRAVITY Provides Evidence the Young, Substellar Companion HD 136164 Ab Formed Like a "Failed Star"
DOI: 10.3847/1538-3881/ad1689 Bibcode: 2024AJ....167...64B

Lutz, D.; Genzel, R.; Sturm, E. +94 more

Young, low-mass brown dwarfs orbiting early-type stars, with low mass ratios (q ≲ 0.01), appear to be intrinsically rare and present a formation dilemma: could a handful of these objects be the highest-mass outcomes of "planetary" formation channels (bottom up within a protoplanetary disk), or are they more representative of the lowest-mass "faile…

2024 The Astronomical Journal
Gaia Hipparcos 4
A Testbed for Tidal Migration: The 3D Architecture of an Eccentric Hot Jupiter HD 118203 b Accompanied by a Possibly Aligned Outer Giant Planet
DOI: 10.3847/1538-3881/ad86c4 Bibcode: 2024AJ....168..295Z

Huber, Daniel; Claytor, Zachary R.; Saunders, Nicholas +32 more

Characterizing outer companions to hot Jupiters plays a crucial role in deciphering their origins. We present the discovery of a long-period giant planet, HD 118203 c ( , au) exterior to a close-in eccentric hot Jupiter HD 118203 b (P b = 6.135 days, m b

2024 The Astronomical Journal
Hipparcos 2
Verification of Astrometrically Accelerating Stars from Hipparcos and Gaia. I. Methodology and Application to HIP 44842
DOI: 10.3847/1538-3881/ad4d8f Bibcode: 2024AJ....168...18M

Tokovinin, Andrei; Makarov, Valeri V.

A large number of candidate binary stars with apparent acceleration on the sky has emerged from analysis of astrometric data collected by the Hipparcos, Tycho-2, and Gaia space missions. Although the apparent acceleration can serve as a relatively reliable indicator of binarity, it provides scarce information about the orbital and physical paramet…

2024 The Astronomical Journal
Gaia Hipparcos 0
Two Long-period Giant Planets around Two Giant Stars: HD 112570 and HD 154391
DOI: 10.3847/1538-3881/ad11de Bibcode: 2024AJ....167...59X

Zhao, Gang; Wang, Wei; Song, Nan +24 more

We present the discoveries of two giant plants orbiting the red-giant-branch star HD 112570 and the red-clump star HD 154391, based on the radial-velocity (RV) measurements from the Xinglong station and Okayama Astrophysical Observatory. Spectroscopic and asteroseismic analyses suggest that HD 112570 has a mass of 1.15 ± 0.12 M , a rad…

2024 The Astronomical Journal
Gaia Hipparcos 0