Extended stellar systems in the solar neighborhood - II. Discovery of a nearby 120° stellar stream in Gaia DR2

Abstract

We report the discovery of a large, dynamically cold, coeval stellar stream that is currently traversing the immediate solar neighborhood at a distance of only 100 pc. The structure was identified in a wavelet decomposition of the 3D velocity space of all stars within 300 pc to the Sun. Its members form a highly elongated structure with a length of at least 400 pc, while its vertical extent measures only about 50 pc. Stars in the stream are not isotropically distributed but instead form two parallel lanes with individual local overdensities, that may correspond to a remnant core of a tidally disrupted cluster or OB association. Its members follow a very well-defined main sequence in the observational Hertzsprung-Russel diagram and also show a remarkably low 3D velocity dispersion of only 1.3 km s${}^{-1}$. These findings strongly suggest a common origin as a single coeval stellar population. An extrapolation of the present-day mass function indicates a total mass of at least 2000 M${}_{\odot }$, making it larger than most currently known clusters or associations in the solar neighborhood. We estimated the stream's age to be around 1 Gyr based on a comparison with a set of isochrones and giant stars in our member selection and find a mean metallicity of $\left[Fe/H\right]=-0.04$. This structure may very well represent the Galactic disk counterpart to the prominent stellar streams observed in the Milky Way halo. As such, it constitutes a new valuable probe to constrain the Galaxy's mass distribution.

accepted for publication in Astronomy & Astrophysics on 17 Jan 2019

References in corpus (7)

• The NumPy array: a structure for efficient numerical computation
• scikit-image: Image processing in Python
• The Gaia mission
• Detection of a 63 Degree Cold Stellar Stream in the Sloan Digital Sky Survey
• The Age and Age Spread of the Praesepe and Hyades Clusters: a Consistent, ~800 Myr Picture from Rotating Stellar Models
• Extended stellar systems in the solar neighborhood - I. The tidal tails of the Hyades
• LACEwING: A New Moving Group Analysis Code

Cited by in corpus (54)

• Painting a portrait of the Galactic disc with its stellar clusters
• Extended stellar systems in the solar neighborhood -- V. Discovery of coronae of nearby star clusters
• Very regular high-frequency pulsation modes in young intermediate-mass stars
• Orbital Clustering Identifies the Origins of Galactic Stellar Streams
• Stellar clustering shapes the architectures of planetary systems
• Significance Mode Analysis (SigMA) for hierarchical structures. An application to the Sco-Cen OB association
• TESS Hunt for Young and Maturing Exoplanets (THYME) V: A Sub-Neptune Transiting a Young Star in a Newly Discovered 250 Myr Association
• TESS Hunt for Young and Maturing Exoplanets (THYME) IV: Three small planets orbiting a 120 Myr-old star in the Pisces--Eridanus stream
• Wide binaries are rare in open clusters
• A precise asteroseismic age and metallicity for HD 139614: a pre-main-sequence star with a protoplanetary disc in Upper-Centaurus Lupus
• Microarcsecond Astrometry: Science Highlights from Gaia
• Earth as a transducer for dark-photon dark-matter detection
• Rotation and Lithium Confirmation of a 500 Parsec Halo for the Open Cluster NGC 2516
• Via Machinae: Searching for Stellar Streams using Unsupervised Machine Learning
• Extended stellar systems in the solar neighborhood - III. Like ships in the night: the Coma Berenices neighbor moving group
• Direct imaging of sub-Jupiter mass exoplanets with James Webb Space Telescope coronagraphy
• The $\mu$ Tau Association: A 60 Myr-Old Coeval Group at 150 pc from the Sun
• The rotation period distribution of the rich Pleiades-age Southern open cluster NGC 2516. Existence of a representative zero-age main sequence distribution
• TESS Hunt for Young and Maturing Exoplanets (THYME) IX: a 27 Myr extended population of Lower-Centaurus Crux with a transiting two-planet system
• Search for dark-photon dark matter in the SuperMAG geomagnetic field dataset
• The $\rho$ Oph region revisited with Gaia EDR3
• New Coronae and Stellar Associations Revealed by a Clustering Analysis of the Solar Neighborhood
• BEAST begins: Sample characteristics and survey performance of the B-star Exoplanet Abundance Study
• TESS Hunt for Young and Maturing Exoplanets (THYME) VII : Membership, rotation, and lithium in the young cluster Group-X and a new young exoplanet
• Five young $\delta$ Scuti stars in the Pleiades seen with Kepler/K2
• First phase space portrait of a hierarchical stellar structure in the Milky Way
• Stellar Population Astrophysics (SPA) with TNG. The old open clusters Collinder 350, Gulliver 51, NGC 7044, and Ruprecht 171
• A Mini-Neptune from TESS and CHEOPS Around the 120 Myr Old AB Dor member HIP 94235
• The GALAH Survey: Chemically tagging the Fimbulthul stream to the globular cluster $\omega$ Centauri
• The impact of massive stars and black holes on the fate of open star clusters and their tidal streams
• Using the Gaia excess uncertainty as a proxy for stellar variability and age
• A Young, Low-Density Stellar Stream in the Milky Way Disk: Theia 456
• Characterising brown dwarf companions with IRDIS long-slit spectroscopy: HD 1160 B and HD 19467 B
• A Census of the 32 Ori Association with Gaia
• Ongoing hierarchical massive cluster assembly: the LISCA II structure in the Perseus complex
• Disconnecting the Dots: Re-Examining the Nature of Stellar "Strings" in the Milky Way
• The Milky Way, Coming into Focus: Precision Astrometry Probes its Evolution, and its Dark Matter
• Towards a fully consistent Milky Way disk model -- IV. The impact of Gaia DR2 and APOGEE
• Pearls on a String: Numerous Stellar Clusters Strung along the Same Orbit
• Robust Clustering of the Local Milky Way Stellar Kinematic Substructures with Gaia eDR3
• Spatial and Kinematic Clustering of Stars in the Galactic Disk
• Examining the Rotation Period Distribution of the 40 Myr Tucana-Horologium Association with TESS
• An empirical isochrone archive for nearby open clusters
• Estimating the ages of open star clusters from properties of their extended tidal tails
• Exploring the directly imaged HD 1160 system through spectroscopic characterization and high-cadence variability monitoring
• A rotational age for the open cluster NGC 2281
• Stellar streams and dark substructure: the diffusion regime
• The cosmic waltz of Coma Berenices and Latyshev 2 (Group X). Membership, phase-space structure, mass, and energy distributions
• TOI-712: a system of adolescent mini-Neptunes extending to the habitable zone
• Confirming the Tidal Tails of the Young Open Cluster Blanco 1 with TESS Rotation Periods
• J-PLUS: Discovery and characterisation of ultracool dwarfs using Virtual Observatory tools II. Second data release and machine learning methodology
• Toward the fabric of the Milky Way I. The density of disk streams from a local $250^3$ pc${}^3$ volume
• Tidal tails in open clusters: Morphology, binary fraction, dynamics, and rotation
• Transit Hunt for Young and Maturing Exoplanets (THYME) VIII: a Pleiades-age association harboring two transiting planetary systems from Kepler