Search Publications
Identifying Bound Stellar Companions to Kepler Exoplanet Host Stars Using Speckle Imaging
Howell, Steve B.; Everett, Mark E.; Horch, Elliott P. +4 more
The Kepler mission and subsequent ground-based follow-up observations have revealed a number of exoplanet host stars with nearby stellar companions. This study presents speckle observations of 57 Kepler objects of interest (KOIs) that are also double stars, each observed over a 3-8 yr period, which has allowed us to track their relative motions wi…
Understanding the Effects of Systematics in Exoplanetary Atmospheric Retrievals
Kempton, Eliza M. -R.; Ih, Jegug
Retrieval of exoplanetary atmospheric properties from their transmission spectra commonly assumes that the errors in the data are Gaussian and independent. However, non-Gaussian noise can occur due to instrumental or stellar systematics and the merging of discrete data sets. We investigate the effect of correlated noise and constrain the potential…
The Solar Neighborhood. XLVII. Comparing M-dwarf Models with Hubble Space Telescope Dynamical Masses and Spectroscopy
Henry, Todd J.; Jao, Wei-Chun; Dieterich, Serge B. +1 more
We use HST/STIS optical spectroscopy of 10 M dwarfs in five closely separated binary systems to test models of M-dwarf structure and evolution. Individual dynamical masses ranging from 0.083 to 0.405 M⊙ for all stars are known from previous work. We first derive temperature, radius, luminosity, surface gravity, and metallicity by fittin…
Large Adaptive Optics Survey for Substellar Objects around Young, Nearby, Low-mass Stars with Robo-AO
Baranec, Christoph; Duev, Dmitry A.; Jensen-Clem, Rebecca +16 more
We present results from the Large Adaptive optics Survey for Substellar Objects, where the goal is to directly image new substellar companions (<70 MJup) at wide orbital separations (≳50 au) around young (≲300 Myr), nearby (<100 pc), low-mass (≈0.1-0.8 ${M}_{\odot }$ ) stars. We report on 427 young stars imaged in the visible (i')…
Another Superdense Sub-Neptune in K2-182 b and Refined Mass Measurements for K2-199 b and c
Batalha, Natalie M.; Rosenthal, Lee J.; Hirsch, Lea A. +10 more
We combine multiple campaigns of K2 photometry with precision radial velocity measurements from Keck-HIRES to measure the masses of three sub-Neptune-sized planets. We confirm the planetary nature of the massive sub-Neptune K2-182 b (P b = 4.7 days, R b = 2.69 R ⊕) and derive refined parameters for K2-199 b and c (…
The K2 M67 Study: Precise Mass for a Turnoff Star in the Old Open Cluster M67
Vanderburg, Andrew; Latham, David W.; Stello, Dennis +8 more
We present a study of the bright detached eclipsing main-sequence binary WOCS 11028 (Sanders 617) in the open cluster M67. Although the binary has only one eclipse per orbital cycle, we show that the masses of the stars can be derived very precisely thanks to a strong constraint on the orbital inclination: MA = 1.222 ± 0.006M⊙
Outbursting Young Stellar Object PGIR 20dci in the Perseus Arm
De, Kishalay; Kasliwal, Mansi M.; Hillenbrand, Lynne A. +9 more
We report the discovery of a likely outbursting Class I young stellar object, associated with the star-forming region NGC 281-W (distance ∼2.8 kpc). The source is currently seen only at infrared wavelengths, appearing in both the Palomar Gattini InfraRed (1.2 µm) and the Near-Earth Object Wide-field Infrared Survey Explorer (3.4 and 4.6 &mic…
Astrometric and Photometric Investigation of Three Old Age Open Clusters in the Gaia Era: Berkeley 32, Berkeley 98, and King 23
Bisht, D.; Yadav, R. K. S.; Rangwal, G. +2 more
Using the photometric and kinematical data from Gaia Data Release 2, three old open clusters namely Berkeley 32 (Be 32), Berkeley 98 (Be 98), and King 23 are investigated. The latter two of these clusters are poorly studied in the literature. The numbers of the most probable cluster members are 563, 260, and 114 for Be 32, Be 98, and King 23, resp…
β Cephei Pulsations in the High-mass Eclipsing System CW Cephei
Hong, Kyeongsoo; Lee, Jae Woo
CW Cep is an early B-type eclipsing binary with mass measurement precisions better than 1%. We report the discovery of pulsation signatures in the Transiting Exoplanet Survey Satellite time-series data of the system observed during Sectors 17 and 18. Our binary modeling indicates that the target star is a partially eclipsing detached system with m…
WIYN Open Cluster Study. LXXXV. Li in NGC 2243: Implications for Stellar and Galactic Evolution
Twarog, Bruce A.; Anthony-Twarog, Barbara J.; Deliyannis, Constantine P.
High-dispersion spectra in the Li λ6708 region have been obtained and analyzed in the old, metal-deficient cluster NGC 2243. From Hydra spectra for 29 astrometric and radial velocity members, we derive rotational velocities, as well as [Fe/H], [Ca/H], [Si/H], and [Ni/H] based on 17, 1, 1, and 3 lines, respectively. Using ROBOSPECT, an automatic eq…