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At least 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

60 Candidate High-velocity Stars Originating from the Sagittarius Dwarf Spheroidal Galaxy in Gaia EDR3

Using proper motions from Gaia Early Data Release 3 (Gaia EDR3) and radial velocities from several surveys, we identify 60 candidate high-velocity stars with a total velocity greater than 75% of the escape velocity that probably originated from the Sagittarius dwarf spheroidal galaxy (Sgr) by orbital analysis. Sgr’s gravity has little effect on the results and the Large Magellanic Cloud’s gravity has a nonnegligible effect on only a few stars. The closest approach of these stars to the Sgr occurred when the Sgr passed its pericenter (~38.2 Myr ago), which suggests they were tidally stripped from the Sgr. The positions of these stars in the Hertzsprung–Russell diagram and the chemical properties of 19 of them with available [Fe/H] are similar to the Sgr stream member stars. This is consistent with the assumption of their accretion origin. Two of the 60 are hypervelocity stars, which may also be produced by the Hills mechanism.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2026

Multi-sensor Observations of a High-velocity Fireball over the South Atlantic on 2026 April 1

A high-velocity fireball was detected over the South Atlantic (41.9°S, 54.7°W) on 2026 April 1 at 02:13:14 UTC by U.S. Government (USG) sensors, with peak brightness at 90.5 km altitude. The event was well-observed from geostationary orbit by two civilian lightning imagers with near-orthogonal geometry, the Geostationary Operational Environmental Satellite-East Geostationary Lightning Mapper (GLM) and the Exploitation of Meteorological Satellites Meteosat Third Generation Imager 1 Lightning Imager, and it produced low-frequency acoustic signatures. The GLM measured a total radiated energy of 2.4 × 10 10 J, corresponding to a calculated impact energy of 0.086 kt TNT equivalent. Stereoscopic triangulation of the imager tracks yields an independent pre-atmospheric velocity of ~57 km s −1 , some 18% below the USG-reported value. Because orbital provenance is acutely sensitive to the entry velocity, whose reported uncertainty could be substantial, this discrepancy is notable. We document the multi-sensor record and identify the analysis required to assess provenance, which a subsequent study will present.

Silber, Elizabeth Allaryce [Sandia National Lab. (↗
DOE OSTI2025

XRISM high-resolution X-ray spectroscopy of Cygnus X-1: Highly ionized iron absorption structures

We present the first high-resolution X-ray spectral analysis of Cygnus X-1 using XRISM. The observation wa3s carried out from 2024 April 7 to 10, covering the orbital phase range 0.65–0.17 during its low/hard state. Taking advantage of the exceptional energy resolution of the Resolve instrument, we examined highly ionized iron absorption lines and characterized the ionization states, column densities, and line-of-sight velocities of the absorbing plasma. Spectral analysis revealed an ionization parameter of $\xi \sim 3$, column densities of a few $\times 10^{21}$ cm$^{-2}$, and a blueshifted velocity of $\sim$100 km s$^{-1}$. The observation was divided into two phases: before and after orbital phase $\phi _{\rm {orb}} = 0.9$, corresponding to non-dipping and dipping intervals. While only weak absorption features were present before $\phi _{\rm {orb}} = 0.9$, strong absorption by He-like and H-like Fe appeared during the dipping phase. We measured equivalent widths of 2.3, 0.4, and 1.2 eV for He-like Fe K$\alpha$ and H-like Ly$\alpha _1$ and Ly$\alpha _2$, respectively—demonstrating the capability of XRISM Resolve to securely detect narrow absorption features of only a few eV. These measurements trace the motion of the absorbing material and offer insight into the kinematics and spatial distribution of the wind in the vicinity of the black hole. These findings enhance our understanding of wind-fed accretion in Cygnus X-1 and highlight the importance of continued high-resolution X-ray observations to further constrain the physical properties of winds and accretion flows in high-mass X-ray binaries.

Astronomy and AstroPhysics↗
DOE OSTI2021

Orbits and Masses of Binaries from Speckle Interferometry at SOAR

We present results from Speckle inteferometric observations of 15 visual binaries and one double-line spectroscopic binary, carried out with the HRCam Speckle camera of the SOAR 4.1 m telescope. These systems were observed as a part of an on-going survey to characterize the binary population in the solar vicinity, out to a distance of 250 pc. We obtained orbital elements and mass sums for our sample of visual binaries. The orbits were computed using a Markov Chain Monte Carlo algorithm that delivers maximum likelihood estimates of the parameters, as well as posterior probability density functions that allow us to evaluate their uncertainty. Their periods cover a range from 5 yr to more than 500 yr; and their spectral types go from early A to mid M, implying total system masses from slightly more than 4M{sub ⊙} down to 0.2M {sub ⊙}. They are located at distances between approximately 12 and 200 pc, mostly at low Galactic latitude. For the double-line spectroscopic binary YSC8, we present the first combined astrometric/radial-velocity orbit resulting from a self-consistent fit, leading to individual component masses of 0.897 ± 0.027 M {sub ⊙} and 0.857 ± 0.026 M {sub ⊙}; and an orbital parallax of 26.61 ± 0.29 mas, which compares very well with the Gaia DR2 trigonometric parallax (26.55 ± 0.27 mas). In combination with published photometry and trigonometric parallaxes, we place our objects on an H-R diagram and discuss their evolutionary status. We also present a thorough analysis of the precision and consistency of the photometry available for them.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2020

Clarissa Family Age from the Yarkovsky Effect Chronology

The Clarissa family is a small collisional family composed of primitive C-type asteroids. It is located in a dynamically stable zone of the inner asteroid belt. In this work we determine the formation age of the Clarissa family by modeling planetary perturbations as well as thermal drift of family members due to the Yarkovsky effect. Simulations were carried out using the SWIFT-RMVS4 integrator modified to account for the Yarkovsky and Yarkovsky–O’Keefe–Radzievskii–Paddack (YORP) effects. We ran multiple simulations starting with different ejection velocity fields of fragments, varying proportion of initially retrograde spins, and also tested different Yarkovsky/YORP models. Our goal was to match the observed orbital structure of the Clarissa family which is notably asymmetrical in the proper semimajor axis, a {sub p}. The best fits were obtained with the initial ejection velocities ≲20 m s{sup −1} of diameter D ≃ 2 km fragments, ∼4:1 preference for spin-up by YORP, and assuming that ≃80% of small family members initially had retrograde rotation. The age of the Clarissa family was found to be t {sub age} = 56 ± 6 Myr for the assumed asteroid density ρ = 1.5 g cm{sup −3}. Small variation of density to smaller or larger value would lead to slightly younger or older age estimates. This is the first case where the Yarkovsky effect chronology has been successfully applied to an asteroid family younger than 100 Myr.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2024

Polarization phenomenon in heavy-ion collisions

The strongly interacting system created in ultrarelativistic nuclear collisions behaves almost as an ideal fluid with rich patterns of the velocity field exhibiting strong vortical structure. Vorticity of the fluid, via spin-orbit coupling, leads to particle spin polarization. Due to the finite orbital momentum of the system, the polarization on average is not zero. It depends on the particle momenta reflecting the spatial variation of the local vorticity. In the last few years, this field experienced a rapid growth due to experimental discoveries of the global and local polarizations. Recent measurements triggered further development of the theoretical description of the spin dynamics and suggestions of several new mechanisms for particle polarization. In this review, we focus mostly on the experimental results. We compare the measurements with the existing theoretical calculations but try to keep the discussion of possible underlying physics at the qualitative level. Future measurements and how they can help to answer open theoretical questions are also discussed. We pay a special attention to the employed experimental methods, as well as to the detector effects and associated corrections to the measurements.

Physics↗
DOE OSTI2023

Pegasus IV: Discovery and Spectroscopic Confirmation of an Ultra-faint Dwarf Galaxy in the Constellation Pegasus

We report the discovery of Pegasus IV, an ultra-faint dwarf galaxy found in archival data from the Dark Energy Camera processed by the DECam Local Volume Exploration Survey. Pegasus IV is a compact, ultra-faint stellar system ( pc; M $_{V}$ = −4.25 ± 0.2 mag) located at a heliocentric distance of . Based on spectra of seven nonvariable member stars observed with Magellan/IMACS, we confidently resolve Pegasus IV’s velocity dispersion, measuring km s$^{−1}$ (after excluding three velocity outliers); this implies a mass-to-light ratio of for the system. From the five stars with the highest signal-to-noise spectra, we also measure a systemic metallicity of [Fe/H] = dex, making Pegasus IV one of the most metal-poor ultra-faint dwarfs. We tentatively resolve a nonzero metallicity dispersion for the system. These measurements provide strong evidence that Pegasus IV is a dark-matter-dominated dwarf galaxy, rather than a star cluster. We measure Pegasus IV’s proper motion using data from Gaia Early Data Release 3, finding (μ $_{α*}$, μ $_{δ}$) = (0.33 ± 0.07, −0.21 ± 0.08) mas yr$^{−1}$. When combined with our measured systemic velocity, this proper motion suggests that Pegasus IV is on an elliptical, retrograde orbit, and is currently near its orbital apocenter. Lastly, we identify three potential RR Lyrae variable stars within Pegasus IV, including one candidate member located more than 10 half-light radii away from the system’s centroid. The discovery of yet another ultra-faint dwarf galaxy strongly suggests that the census of Milky Way satellites is still incomplete, even within 100 kpc.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2025

The Cocytos Stream: A Disrupted Globular Cluster from our Last Major Merger?

The census of stellar streams and dwarf galaxies in the Milky Way provides direct constraints on galaxy formation models and the nature of dark matter. The DESI Milky Way survey (with a footprint of 14,000$~deg{^2}$ and a depth of $r<19$ mag) delivers the largest sample of distant metal-poor stars compared to previous optical fiber-fed spectroscopic surveys. This makes DESI an ideal survey to search for previously undetected streams and dwarf galaxies. We present a detailed characterization of the Cocytos stream, which was re-discovered using a clustering analysis with a catalog of giants in the DESI year 3 data, supplemented with Magellan/MagE spectroscopy. Our analysis reveals a relatively metal-rich ([Fe/H]$=-1.3$) and thick stream (width$=1.5^\circ$) at a heliocentric distance of $\approx 25$ kpc, with an internal velocity dispersion of 6.5-9 km s$^{-1}$. The stream's metallicity, radial orbit, and proximity to the Virgo stellar overdensities suggest that it is most likely a disrupted globular cluster that came in with the Gaia-Enceladus merger. We also confirm its association with the Pyxis globular cluster. Our result showcases the ability of wide-field spectroscopic surveys to kinematically discover faint disrupted dwarfs and clusters, enabling constraints on the dark matter distribution in the Milky Way.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

Mobile orbitons in Ca 2 CuO 3 : Crucial role of Hund's exchange

We investigate the Cu L 3 edge resonant inelastic x-ray scattering (RIXS) spectra of a quasi-1D antiferromagnet Ca 2 CuO 3 . In addition to the magnetic excitations, which are well-described by the two-spinon continuum, we observe two dispersive orbital excitations, the 3d xy and the 3d yz orbitons. We carry out a quantitative comparison of the RIXS spectra, obtained with two distinct incident polarizations, with a theoretical model. We show that any realistic spin-orbital model needs to include a finite, but realistic, Hund's exchange J H ≈ 0.5 eV . Its main effect is an increase in orbiton velocities, so that their theoretically calculated values match those observed experimentally. Even though Hund's exchange also mediates some interaction between spinon and orbiton, the picture of spin-orbit separation remains intact and describes orbiton motion in this compound.

1-dimensional spin chains↗
DOE OSTI2020

Cluster Difference Imaging Photometric Survey. II. TOI 837: A Young Validated Planet in IC 2602

We report the discovery of TOI 837b and its validation as a transiting planet. We characterize the system using data from the NASA Transiting Exoplanet Survey Satellite mission, the ESA Gaia mission, ground-based photometry from El Sauce and ASTEP400, and spectroscopy from CHIRON, FEROS, and Veloce. We find that TOI 837 is a T = 9.9 mag G0/F9 dwarf in the southern open cluster IC 2602. The star and planet are therefore 35$_{-5}^{+11}$ million years old. Combining the transit photometry with a prior on the stellar parameters derived from the cluster color–magnitude diagram, we find that the planet has an orbital period of 8.3 days and is slightly smaller than Jupiter (R p =0.77$_{-0.07}^{+0.09}$ R Jup ). From radial velocity monitoring, we limit M p sin i to less than 1.20 M Jup (3σ). The transits either graze or nearly graze the stellar limb. Grazing transits are a cause for concern, as they are often indicative of astrophysical false-positive scenarios. Our follow-up data show that such scenarios are unlikely. Our combined multicolor photometry, high-resolution imaging, and radial velocities rule out hierarchical eclipsing binary scenarios. Background eclipsing binary scenarios, though limited by speckle imaging, remain a 0.2% possibility. TOI 837b is therefore a validated adolescent exoplanet. The planetary nature of the system can be confirmed or refuted through observations of the stellar obliquity and the planetary mass. Such observations may also improve our understanding of how the physical and orbital properties of exoplanets change in time.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2021

Dissecting the Quadruple Binary Hyad vA 351 Masses for Three M Dwarfs and a White Dwarf

We extend results first announced by Franz et al., that identified vA 351 = H346 in the Hyades as a multiple star system containing a white dwarf. With Hubble Space Telescope Fine Guidance Sensor fringe tracking and scanning, and more recent speckle observations, all spanning 20.7 years, we establish a parallax, relative orbit, and mass fraction for two components, with a period, P=2.70 yr and total mass 2.1 M{sub ⊙}. With ground-based radial velocities from the McDonald Observatory Otto Struve 2.1 m Telescope Sandiford Spectrograph, and Center for Astrophysics Digital Speedometers, spanning 37 years, we find that component B consists of BC, two M dwarf stars orbiting with a very short period (P{sub BC}=0.749 days), having a mass ratio M{sub C}/M{sub B} = 0.95. We confirm that the total mass of the system can only be reconciled with the distance and component photometry by including a fainter, higher-mass component. The quadruple system consists of three M dwarfs (A, B, C) and one white dwarf (D). We determine individual M dwarf masses M{sub A} = 0.53 ± 0.10 M{sub ⊙}, M{sub B} = 0.43 ± 0.04 M{sub ⊙}, and M{sub C} = 0.41 ± 0.04 M{sub ⊙}. The white dwarf mass, 0.54 ± 0.04 M{sub ⊙}, comes from cooling models, an assumed Hyades age of 670 Myr, and consistency with all previous and derived astrometric, photometric, and radial velocity results. Velocities from Hα and He i emission lines confirm the BC period derived from absorption lines, with similar (He i) and higher (Hα) velocity amplitudes. We ascribe the larger Hα amplitude to emission from a region each component shadows from the other, depending on the line of sight.

47 OTHER INSTRUMENTATION↗
DOE OSTI2023

TESS giants transiting giants V – two hot Jupiters orbiting red giant hosts

ABSTRACT In this work, we present the discovery and confirmation of two hot Jupiters orbiting red giant stars, TOI-4377 b and TOI-4551 b, observed by Transiting Exoplanet Survey Satellite in the Southern ecliptic hemisphere and later followed-up with radial-velocity (RV) observations. For TOI-4377 b, we report a mass of $0.957^{+0.089}_{-0.087} \ M_\mathrm{J}$ and a inflated radius of 1.348 ± 0.081 RJ orbiting an evolved intermediate-mass star (1.36 M⊙ and 3.52 R⊙; TIC 394918211) on a period of of 4.378 d. For TOI-4551 b, we report a mass of 1.49 ± 0.13 MJ and a radius that is not obviously inflated of $1.058^{+0.110}_{-0.062} \ R_\mathrm{J}$, also orbiting an evolved intermediate-mass star (1.31 M⊙ and 3.55 R⊙; TIC 204650483) on a period of 9.956 d. We place both planets in context of known systems with hot Jupiters orbiting evolved hosts, and note that both planets follow the observed trend of the known stellar incident flux-planetary radius relation observed for these short-period giants. Additionally, we produce planetary interior models to estimate the heating efficiency with which stellar incident flux is deposited in the planet’s interior, estimating values of $1.91 \pm 0.48~{{\ \rm per\ cent}}$ and $2.19 \pm 0.45~{{\ \rm per\ cent}}$ for TOI-4377 b and TOI-4551 b, respectively. These values are in line with the known population of hot Jupiters, including hot Jupiters orbiting main-sequence hosts, which suggests that the radii of our planets have re-inflated in step with their parent star’s brightening as they evolved into the post-main sequence. Finally, we evaluate the potential to observe orbital decay in both systems.

Pereira, Filipe (ORCID:0000000221577146)↗
DOE OSTI2020

Experimental investigation of turbulent wake flows in a helically wrapped rod bundle in presence of localized blockages

In nuclear sodium fast reactors, bundles of rods are tightly packed into a triangular lattice, enclosed in a hexagonal duct, and each pin is spirally wrapped with a thin wire. Flow blockages can potentially impact the local flow characteristics and heat transfer mechanisms in the bundle due to its small subchannel size. The effects of the blockage on the flow structures and heat transfer mechanisms are important aspects that require an accurate investigation. In this study, the flow-field characteristics in the vicinity of a blockage located in the exterior subchannel of rod bundles with helically wrapped wires were experimentally investigated. The velocity fields in the exterior subchannel were acquired by applying matched-index-of-refraction and time-resolved particle image velocimetry (TR-PIV) techniques for Reynolds numbers of Re 1 = 4000 and Re 2 = 17 000, i.e., equivalent to Rew 1 = 19 600 and Rew 2 = 83 200, respectively, based on the blockage width. The results from the TR-PIV measurements revealed an arch-shaped vortex with a large flow recirculation and a pair of counter-rotating vortices in the wake region downstream of the blockage, which is commonly observed in the wake flow of bluff bodies. The relative lateral distance and angle between the two vortices decreased when the Reynolds numbers increased. Profiles of maximum turbulence intensity along the shear layers illustrated the transition process including the growth, peak, and decay along the flow direction. From the spectral analysis of the turbulent velocities extracted at points along the shear layer, the Strouhal numbers ( St ) representing the vortex shedding frequency were found to be St = 0.25 and St = 0.56 for the left and right shear layers, respectively. Characteristics of shear layers generated by the blockage in the exterior subchannel were investigated via the two-point cross correlation of fluctuating velocities. The patiotemporal cross correlations of turbulent velocities, computed at points in the region where the left shear layer exhibited rolling effects and vortex breakdowns, were considerably wider and longer. The convection velocity U c was estimated to be ~0.82 U m to 0.93 U m . Proper orthogonal decomposition (POD) analysis was applied to the instantaneous velocity fields to extract the statistically dominant flow structures. It was found that POD modes 2–3 and 4–5 formed the pair modes when the corresponding POD temporal coefficients depicted sinusoidal shapes and exhibited nearly circular orbits in the phase space. Spectral analysis of the POD temporal coefficients confirmed the vortex shedding frequencies detected in the analysis of turbulent velocities.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2020

TOI-677b: A Warm Jupiter (P = 11.2 days) on an Eccentric Orbit Transiting a Late F-type Star

We report the discovery of TOI-677 b, first identified as a candidate in light curves obtained within Sectors 9 and 10 of the Transiting Exoplanet Survey Satellite (TESS) mission and confirmed with radial velocities. TOI-677 b has a mass of M{sub p} = 1.236{sub −0.067}{sup +0.069} M{sub J}, a radius of R{sub P} = 1.170±0.03 R{sub J}, and orbits its bright host star (V = 9.8 mag) with an orbital period of 11.23660±0.00011 d, on an eccentric orbit with e=0.435±0.024. The host star has a mass of M{sub ⋆} = 1.181±0.058 M{sub ⊙}, a radius of R{sub ⋆} = 1.28{sub −0.03}{sup +0.03} R{sub ⊙}, an age of 2.92{sub −0.73}{sup +0.80} Gyr and solar metallicity, properties consistent with a main-sequence late-F star with T{sub eff}=6295±77 K. We find evidence in the radial velocity measurements of a secondary long-term signal, which could be due to an outer companion. The TOI-677 b system is a well-suited target for Rossiter–Mclaughlin observations that can constrain migration mechanisms of close-in giant planets.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

A Highly Eccentric Warm Jupiter Orbiting TIC 237913194

The orbital parameters of warm Jupiters serve as a record of their formation history, providing constraints on formation scenarios for giant planets on close and intermediate orbits. Here, we report the discovery of TIC 237913194b, detected in full-frame images from Sectors 1 and 2 of the Transiting Exoplanet Survey Satellite (TESS), ground-based photometry (Chilean–Hungarian Automated Telescope, Las Cumbres Observatory Global Telescope), and Fiber-fed Extended Range Optical Spectrograph radial velocity time series. We constrain its mass to M P = 1.942 -0.091 +0.091 M J and its radius to R P = 1.117 -0.047 +0.054 R J , implying a bulk density similar to Neptune’s. It orbits a G-type star (M &lowast; = 1.026 -0.055 +0.057 M ⊙ , V = 12.1 mag) with a period of 15.17 days on one of the most eccentric orbits of all known warm giants (e ≈ 0.58). This extreme dynamical state points to a past interaction with an additional, undetected massive companion. A tidal evolution analysis showed a large tidal dissipation timescale, suggesting that the planet is not a progenitor for a hot Jupiter caught during its high-eccentricity migration. TIC 237913194b further represents an attractive opportunity to study the energy deposition and redistribution in the atmosphere of a warm Jupiter with high eccentricity.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2023

Characterization of Low-mass Companions to Kepler Objects of Interest Observed with APOGEE-N

We report the characterization of 28 low-mass (0.02 M ⊙ ≤ M 2 ≤ 0.25 M ⊙ ) companions to Kepler objects of interest (KOIs), eight of which were previously designated confirmed planets. These objects were detected as transiting companions to Sunlike stars (G and F dwarfs) by the Kepler mission and are confirmed as single-lined spectroscopic binaries in the current work using the northern multiplexed Apache Point Observatory Galactic Evolution Experiment near-infrared spectrograph (APOGEE-N) as part of the third and fourth Sloan Digital Sky Surveys. We have observed hundreds of KOIs using APOGEE-N and collected a total of 43,175 spectra with a median of 19 visits and a median baseline of ~1.9 yr per target. We jointly model the Kepler photometry and APOGEE-N radial velocities to derive fundamental parameters for this subset of 28 transiting companions. The radii for most of these low-mass companions are overinflated (by ~10%) when compared to theoretical models. Tidally locked M dwarfs on short-period orbits show the largest amount of inflation, but inflation is also evident for companions that are well separated from the host star. We demonstrate that APOGEE-N data provide reliable radial velocities when compared to precise high-resolution spectrographs that enable detailed characterization of individual systems and the inference of orbital elements for faint (H > 12) KOIs. The data from the entire APOGEE-KOI program are public and present an opportunity to characterize an extensive subset of the binary population observed by Kepler.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2023

Orbital evolution of satellite galaxies in self-interacting dark matter models

Dark matter self-interactions can leave distinctive signatures on the properties of satellite galaxies around Milky Way–like hosts through their impact on tidal stripping, ram pressure, and gravothermal collapse. We delineate the regions of self-interacting dark matter parameter space—specified by interaction cross section and a velocity scale—where each of these effects dominates and show how the relative mass loss depends on the satellite’s initial mass, density profile, and orbit. We obtain novel, conservative constraints in this parameter space using Milky Way satellite galaxies with notably high central densities and small pericenter distances. Furthermore, our results for self-interacting dark matter models, in combination with constraints from clusters of galaxies, favor either velocity-dependent cross sections that lead to gravothermal core collapse in the densest satellites or small cross sections which more closely resemble cold and collisionless dark matter.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2022

S $^{5}$: The Orbital and Chemical Properties of One Dozen Stellar Streams

We report the kinematic, orbital, and chemical properties of 12 stellar streams with no evident progenitors using line-of-sight velocities and metallicities from the Southern Stellar Stream Spectroscopic Survey (S $^{5}$), proper motions from Gaia EDR3, and distances derived from distance tracers or the literature. This data set provides the largest homogeneously analyzed set of streams with full 6D kinematics and metallicities. All streams have heliocentric distances between ∼10 and 50 kpc. The velocity and metallicity dispersions show that half of the stream progenitors were disrupted dwarf galaxies (DGs), while the other half originated from disrupted globular clusters (GCs), hereafter referred to as DG and GC streams. Based on the mean metallicities of the streams and the mass–metallicity relation, the luminosities of the progenitors of the DG streams range between those of Carina and Ursa Major I (−9.5 ≲ M $_{V}$ ≲ −5.5). Four of the six GC streams have mean metallicities of Fe/H < −2, more metal poor than typical Milky Way (MW) GCs at similar distances. Interestingly, the 300S and Jet GC streams are the only streams on retrograde orbits in our dozen-stream sample. Finally, we compare the orbital properties of the streams with known DGs and GCs in the MW, finding several possible associations. Some streams appear to have been accreted with the recently discovered Gaia–Enceladus–Sausage system, and others suggest that GCs were formed in and accreted together with the progenitors of DG streams whose stellar masses are similar to those of Draco to Carina (∼10$^{5}$–10$^{6}$ M $_{⊙}$).

79 ASTRONOMY AND ASTROPHYSICS↗