Search Publications
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}<…
Dancing Twins: Stellar Hierarchies That Formed Sequentially?
Tokovinin, Andrei
This paper draws attention to the class of resolved triple stars with moderate ratios of inner and outer periods (possibly in a mean motion resonance) and nearly circular, mutually aligned orbits. Moreover, stars in the inner pair are twins with almost identical masses, while the mass sum of the inner pair is comparable to the mass of the outer co…
A New Hyper-runaway Star Discovered from LAMOST and Gaia: Ejected Almost in the Galactic Rotation Direction
Zhao, Gang; Zhao, Jing-Kun; Huang, Yang +11 more
In this paper, we report the discovery of a new late-B-type unbound hyper-runaway star (LAMOST-HVS4) from the LAMOST spectroscopic surveys. According to its atmospheric parameters, it is either a B-type main-sequence (MS) star or a blue horizontal branch (BHB) star. Its Galactocentric distance and velocity are 30.3 ± 1.6 kpc and 586 ± 7 km s-…