Search Publications
Stellar Rotation in the K2 Sample: Evidence for Modified Spin-down
Davenport, James R. A.; Angus, Ruth; Foreman-Mackey, Daniel +5 more
We analyze light curves of 284,834 unique K2 targets using a Gaussian process model with a quasi-periodic kernel function. By cross-matching K2 stars to observations from Gaia Data Release 2, we have identified 69,627 likely main-sequence stars. From these we select a subsample of 8977 stars on the main sequence with highly precise rotation period…
TESS Observations of the Luhman 16 AB Brown Dwarf System: Rotational Periods, Lightcurve Evolution, and Zonal Circulation
Apai, Dániel; Bedin, Luigi R.; Nardiello, Domenico
Brown dwarfs were recently found to display rotational modulations, commonly attributed to cloud cover of varying thickness, possibly modulated by planetary-scale waves. However, the long-term, continuous, high-precision monitoring data to test this hypothesis for more objects is lacking. By applying our novel photometric approach to Transiting Ex…
Eridanus IV: an Ultra-faint Dwarf Galaxy Candidate Discovered in the DECam Local Volume Exploration Survey
Zenteno, A.; James, D. J.; Kuropatkin, N. +30 more
We present the discovery of a candidate ultra-faint Milky-Way satellite, Eridanus IV (DELVE J0505-0931), detected in photometric data from the DECam Local Volume Exploration survey (DELVE). Eridanus IV is a faint (MV = - 4.7 ± 0.2), extended ( ${r}_{1/2}={75}_{-13}^{+16}\,\mathrm{pc}$ ), and elliptical (ϵ = 0.54 ± 0.1) system at a helio…
METAL: The Metal Evolution, Transport, and Abundance in the Large Magellanic Cloud Hubble Program. II. Variations of Interstellar Depletions and Dust-to-gas Ratio within the LMC
Jenkins, Edward B.; Yanchulova Merica-Jones, Petia; Gordon, Karl D. +9 more
A key component of the baryon cycle in galaxies is the depletion of metals from the gas to the dust phase in the neutral interstellar medium (ISM). The METAL (Metal Evolution, Transport, and Abundance in the Large Magellanic Cloud) program on the Hubble Space Telescope acquired UV spectra toward 32 sight lines in the half-solar metallicity LMC, fr…
Coronal Hole Detection and Open Magnetic Flux
Temmer, Manuela; Vršnak, Bojan; Pinto, Rui F. +14 more
Many scientists use coronal hole (CH) detections to infer open magnetic flux. Detection techniques differ in the areas that they assign as open, and may obtain different values for the open magnetic flux. We characterize the uncertainties of these methods, by applying six different detection methods to deduce the area and open flux of a near-disk …
A Massive Quiescent Galaxy Confirmed in a Protocluster at z = 3.09
Tamura, Yoichi; Kohno, Kotaro; Steidel, Charles C. +10 more
We report a massive quiescent galaxy at ${z}_{\mathrm{spec}}={3.0922}_{-0.004}^{+0.008}$ spectroscopically confirmed at a protocluster in the SSA22 field by detecting the Balmer and Ca II absorption features with the multi-object spectrometer for infrared exploration on the Keck I telescope. This is the most distant quiescent galaxy confirmed in a…
A Duality in the Origin of Bulges and Spheroidal Galaxies
Pérez-González, Pablo G.; Costantin, Luca; Koekemoer, Anton M. +11 more
Studying the resolved stellar populations of the different structural components that build massive galaxies directly unveils their assembly history. We aim at characterizing the stellar population properties of a representative sample of bulges and pure spheroids in massive galaxies (M⋆ > 1010 M⊙) in the GOODS-…
From Starspots to Stellar Coronal Mass Ejections—Revisiting Empirical Stellar Relations
Papaioannou, Athanasios; Herbst, Konstantin; Airapetian, Vladimir S. +1 more
Upcoming missions, including the James Webb Space Telescope, will soon characterize the atmospheres of terrestrial-type exoplanets in habitable zones around cool K- and M-type stars by searching for atmospheric biosignatures. Recent observations suggest that the ionizing radiation and particle environment from active cool planet hosts may be detri…
An Isolated White Dwarf with a 70 s Spin Period
Bergeron, P.; Kilic, Mukremin; Moss, Adam G. +2 more
We report the discovery of an isolated white dwarf with a spin period of 70 s. We obtained high-speed photometry of three ultramassive white dwarfs within 100 pc and discovered significant variability in one. SDSS J221141.80+113604.4 is a 1.27 M ⊙ (assuming a CO core) magnetic white dwarf that shows 2.9% brightness variations in the BG4…
Three-dimensional Distribution of the Interstellar Dust in the Milky Way
Huang, Y.; Chen, B. -Q.; Yuan, H. -B. +6 more
We present a three-dimensional (3D) extinction map of the southern sky. The map covers the SkyMapper Southern Survey (SMSS) area of ∼14,000 deg2 and has spatial resolutions between 6'9 and 27'. Based on the multi-band photometry of SMSS, the Two Micron All Sky Survey, the Wide-Field Infrared Survey Explorer Survey, and the Gaia mission,…