Search Publications
The Solar Neighborhood. XLV. The Stellar Multiplicity Rate of M Dwarfs Within 25 pc
Henry, Todd J.; Winters, Jennifer G.; Jao, Wei-Chun +6 more
We present results of the largest, most comprehensive study ever done of the stellar multiplicity of the most common stars in the Galaxy, the red dwarfs. We have conducted an all-sky volume-limited survey for stellar companions to 1120 M dwarf primaries known to lie within 25 pc of the Sun via trigonometric parallaxes. In addition to a comprehensi…
The Hubble Space Telescope PanCET Program: Exospheric Mg II and Fe II in the Near-ultraviolet Transmission Spectrum of WASP-121b Using Jitter Decorrelation
Nikolov, Nikolay; Mikal-Evans, Thomas; Sing, David K. +18 more
We present Hubble Space Telescope (HST) near-ultraviolet (NUV) transits of the hot Jupiter WASP-121b, acquired as part of the PanCET program. Time-series spectra during two transit events were used to measure the transmission spectra between 2280 and 3070 Å at a resolution of 30,000. Using HST data from 61 Space Telescope Imaging Spectrograph visi…
Three Red Suns in the Sky: A Transiting, Terrestrial Planet in a Triple M-dwarf System at 6.9 pc
Barclay, Thomas; Latham, David W.; Berlind, Perry +40 more
We present the discovery from Transiting Exoplanet Survey Satellite (TESS) data of LTT 1445Ab. At a distance of 6.9 pc, it is the second nearest transiting exoplanet system found to date, and the closest one known for which the primary is an M dwarf. The host stellar system consists of three mid-to-late M dwarfs in a hierarchical configuration, wh…
Disentangling the Planet from the Star in Late-Type M Dwarfs: A Case Study of TRAPPIST-1g
Bourrier, V.; Wakeford, H. R.; Lewis, N. K. +10 more
The atmospheres of late M stars represent a significant challenge in the characterization of any transiting exoplanets because of the presence of strong molecular features in the stellar atmosphere. TRAPPIST-1 is an ultracool dwarf, host to seven transiting planets, and contains its own molecular signatures that can potentially be imprinted on pla…
Compositions of Planetary Debris around Dusty White Dwarfs
Zuckerman, B.; Dufour, Patrick; Xu, Siyi +5 more
The photospheres of some white dwarfs (WDs) are “polluted” by accretion of material from their surrounding planetary debris. WDs with dust disks are often heavily polluted and high-resolution spectroscopic observations of these systems can be used to infer the chemical compositions of extrasolar planetary material. Here, we report spectroscopic ob…
LRG-BEASTS: Transmission Spectroscopy and Retrieval Analysis of the Highly Inflated Saturn-mass Planet WASP-39b
Kirk, James; López-Morales, Mercedes; Espinoza, Néstor +5 more
We present a ground-based transmission spectrum and comprehensive retrieval analysis of the highly inflated Saturn-mass planet WASP-39b. We obtained low-resolution spectra (R ≈ 400) of a transit of WASP-39b using the ACAM instrument on the 4.2 m William Herschel Telescope as part of the LRG-BEASTS survey. Our transmission spectrum is in good agree…
HyDRA-H: Simultaneous Hybrid Retrieval of Exoplanetary Emission Spectra
Madhusudhan, Nikku; Gandhi, Siddharth; Hawker, George +1 more
High-resolution Doppler spectroscopy has been used to detect several chemical species in exoplanetary atmospheres. Such detections have traditionally relied on cross correlation of observed spectra against spectral model templates, an approach that is successful for detecting chemical species but not optimized for constraining abundances. Recent w…
A Hubble PanCET Study of HAT-P-11b: A Cloudy Neptune with a Low Atmospheric Metallicity
Nikolov, Nikolay; Mikal-Evans, Thomas; Sing, David K. +14 more
We present the first comprehensive look at the 0.35-5 µm transmission spectrum of the warm (∼800 K) Neptune HAT-P-11b derived from 13 individual transits observed using the Hubble and Spitzer Space Telescopes. Along with the previously published molecular absorption feature in the 1.1-1.7 µm bandpass, we detect a distinct absorption fe…
On the Ubiquity and Stellar Luminosity Dependence of Exocometary CO Gas: Detection around M Dwarf TWA 7
Bayo, A.; Wilner, D. J.; Olofsson, J. +2 more
Millimeter observations of CO gas in planetesimal belts show a high detection rate around A stars, but few detections for later type stars. We present the first CO detection in a planetesimal belt around an M star, TWA 7. The optically thin CO (J = 3-2) emission is colocated with previously identified dust emission from the belt, and the emission …
Distant Comet C/2017 K2 and the Cohesion Bottleneck
Mutchler, Max; Jewitt, David; Agarwal, Jessica +3 more
The distant long-period comet C/2017 K2 (PANSTARRS) has been outside the planetary region of the solar system for ∼3 Myr, negating the possibility that heat retained from the previous perihelion could be responsible for its activity. This inbound comet is also too cold for water ice to sublimate and too cold for amorphous water ice, if present, to…