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A Larger Extent for the Ophiuchus Stream
Caldwell, Nelson; Price-Whelan, Adrian M.; Bonaca, Ana +2 more
We present new kinematic data for the Ophiuchus stellar stream. Spectra have been taken of member candidates at the MMT telescope using Hectospec, Hectochelle, and Binospec, which provide more than 1800 new velocities. Combined with proper-motion measurements of stars in the field by the Gaia—DR2 catalog, we have derived stream membership probabil…
The Big Sibling of AU Mic: A Cold Dust-rich Debris Disk around CP-72 2713 in the β Pic Moving Group
Pascucci, Ilaria; Pál, András; Hughes, A. Meredith +8 more
Analyzing Spitzer and Herschel archival measurements we identified a debris disk around the young K7/M0 star CP-72 2713. The system belongs to the 24 Myr old β Pic moving group. Our new 1.33 mm continuum observation, obtained with the Atacama Large Millimeter/submillimeter Array 7 m array, revealed an extended dust disk with a peak radius of 140 a…
A Multiwavelength Search for Intrinsic Linear Polarization in Wolf-Rayet Winds
Moffat, Anthony F. J.; Fullard, Andrew G.; Manset, Nadine +3 more
Wolf-Rayet stars have strong, hot winds, with mass-loss rates at least a factor of 10 greater than their O-star progenitors, although their terminal wind speeds are similar. In this paper, we use the technique of multiband linear polarimetry to extract information on the global asymmetry of the wind in a sample of 47 bright Galactic WR stars. Our …
Low-activity Main-belt Comet 133P/Elst-Pizarro: New Constraints on Its Albedo, Temperature, and Active Mechanism from a Thermophysical Perspective
Ip, Wing-Huen; Hsia, Chih Hao; Yu, Liang Liang
133P/Elst-Pizarro is the first recognized main-belt comet, but we still know little about its nucleus. First we use mid-infrared data of Spitzer MIPS, Spitzer IRS, and the Wide-field Infrared Survey Explorer to estimate its effective diameter, ${D}_{\mathrm{eff}}={3.9}_{-0.3}^{+0.4}$ km, geometric albedo, ${p}_{{\rm{v}}}=0.074\pm 0.013$ , and mean…
Imaging the 44 au Kuiper Belt Analog Debris Ring around HD 141569A with GPI Polarimetry
Matthews, Brenda C.; Duchêne, Gaspard; Esposito, Thomas M. +54 more
We present the first polarimetric detection of the inner disk component around the pre-main-sequence B9.5 star HD 141569A. Gemini Planet Imager H-band (1.65 µm) polarimetric differential imaging reveals the highest signal-to-noise ratio detection of this ring yet attained and traces structure inward to 0.″25 (28 au at a distance of 111 pc). …
Statistical Analysis of Binary Stars from the Gaia Catalog Data Release 2
Zavada, Petr; Píška, Karel
We have developed a general statistical procedure for analysis of 2D and 3D finite patterns, which is applied to the data from recently released Gaia-ESA catalog DR2. The 2D analysis clearly confirms our former results on the presence of binaries in the former DR1 catalog. Our main objective is the statistical 3D analysis of DR2. For this, it is e…
PTFO 8-8695: Two Stars, Two Signals, No Planet
Winn, J. N.; Collins, K. A.; Jenkins, J. M. +13 more
PTFO 8-8695 (CVSO 30) is a star in the 7-10 million year old Orion OB1a cluster that shows brightness dips that resemble planetary transits. Although strong evidence against the planet hypothesis has been presented, the possibility remains debated in the literature. To obtain further clues, we inspected data from the NASA Transiting Exoplanet Surv…
ALMA Observations of the Extraordinary Carina Pillars: HH 901/902
Ho, Paul T. P.; Mesa-Delgado, Adal; Toalá, Jesús A. +4 more
We present Atacama Large Millimeter/Submillimeter Array 1.3 mm continuum and C18O(2-1), N2D+(3-2), 13CS(5-4), and 12CO(2-1) line sensitive and high angular resolution (∼0"3) observations of the famous Carina pillars and protostellar objects HH 901/902. Our observations reveal for the first tim…
The Relation of the Alpha Persei Star Cluster with the Nearby Stellar Stream
Carraro, Giovanni; Seleznev, Anton F.; Kulesh, Maxim V. +1 more
A map of 100° on a side extracted from Gaia DR2 and centered on Alpha Persei reveals two distinct structures—the Alpha Persei star cluster and a conspicuous stellar stream, as widely documented in recent literature. In this work we employ DBSCAN to assess individual stars' membership and attempt at separating stars belonging to the cluster and to …
High-resolution Spectral Discriminants of Ocean Loss for M-dwarf Terrestrial Exoplanets
Lustig-Yaeger, Jacob; Meadows, Victoria S.; Leung, Michaela
In the near future, extremely large ground-based telescopes may conduct some of the first searches for life beyond the solar system. High spectral resolution observations of reflected light from nearby exoplanetary atmospheres could be used to search for the biosignature oxygen. However, while Earth's abundant O2 is photosynthetic, earl…