Gaia DR2 Data Research Articles

The Initial-Final Mass Relation from Carbon Stars in Open Clusters

Recently, Marigo et al, identified a kink in the initial-final mass relation around initial masses of Mini≈1.65−2.10M⊙, based on Gaia DR2 and EDR3 data for white dwarfs in open clusters aged 1.5–2.5 Gyr. Notably, the white dwarfs associated with this kink, all from NGC 7789, exhibit masses of ∼0.70–0.74 M⊙, usually associated with stars of Mini∼ 3–4 M⊙. This kink in the Mini mass range coincides with the theoretically accepted solar metallicity lowest-mass stars evolving into carbon stars during the AGB phase. According to Marigo et al., these carbon stars likely experienced shallow third dredge-up events, resulting in low photospheric C/O ratios and, consequently, middle stellar winds. Under such conditions, the AGB phase is prolonged, allowing for further core mass growth beyond typical predictions. If this occurs, it might provoke other anomalies, such as a non-standard surface chemical composition. We have conducted a chemical analysis of several carbon stars belonging to open clusters within the above cluster ages. Our chemical analysis reveals that the carbon stars found within the kink exhibit C/O ratios only slightly above the unity and the typical chemical composition expected for carbon stars of near solar metallicity, partially validating the above theoretical predictions. We also show that this kink in the IMFR strongly depends on the method used to derived the distances (luminosity) of these carbon stars.

Verification of Hypervelocity Bulge Red Clump Stars

We verify candidate hypervelocity red clump stars located in the Galactic bulge that were selected based on the VVV and the Gaia DR2 data by Luna et al. To do so, we analyze data from the OGLE-IV survey: difference images and astrometric time series. We have data for 30 stars out of 34 hypervelocity candidates. We confirmed the high proper motion of only one of these stars and find out that it is a nearby one, hence, not a hypervelocity star. To sum up, we do not confirm the candidate stars as hypervelocity ones. Hence, we disprove the production rate of hypervelocity red clump stars by the central supermassive black hole provided by Luna et al.

Gaia uncovers difference in B and Be star binarity at small scales: evidence for mass transfer causing the Be phenomenon

ABSTRACT Be stars make up almost 20 per cent of the B star population, and are rapidly rotating stars surrounded by a disc; however the origin of this rotation remains unclear. Mass transfer within close binaries provides the leading hypothesis, with previous detections of stripped companions to Be stars supporting this. Here, we exploit the exquisite astrometric precision of Gaia to carry out the largest to date comparative study into the binarity of matched samples of nearby B and Be stars from the Bright Star Catalogue. By utilizing new ‘proper motion anomaly’ values, derived from Gaia DR2 and DR3 astrometric data alongside previous values calculated using Hipparcos and Gaia data, and the Gaia-provided RUWE, we demonstrate that we can identify unresolved binaries down to separations of 0.02 arcsec. Using these measures, we find that the binary fractions of B and Be stars are similar between 0.04 and 10 arcsec, but the Be binary fraction is significantly lower than that of the B stars for separations below 0.04 arcsec. As the separation range of these ‘missing’ binaries is too large for mass transfer, and stripped companions are not retrieved by these measures, we suggest the companions migrate inwards via binary hardening within a triple system. This confirms statistically for the first time the hypothesis that binary interaction causes the Be phenomenon, with migration causing the dearth of Be binaries between 0.02 and 0.04 arcsec. Furthermore, we suggest that triplicity plays a vital role in this migration, and thus in the formation of Be stars as a whole.

Statistical Analysis of the Probability of Interaction of Globular Clusters with Each Other and with the Galactic Center on the Cosmological Time Scale According to Gaia DR2 Data

This study is aimed at investigating the dynamic evolution of the orbits of stellar globular clusters (GCs). To integrate the orbits backward in time, the authors use models of the time-varying potentials derived from cosmological simulations, which are closest to the potential of the Galaxy. This allows for estimating the probability of close passages (collisions) of GCs with respect to each other and the Galactic center (GalC) in the Galaxy undergoing dynamic changes in the past. To reproduce the dynamics of the Galaxy in time, five potentials selected from the IllustrisTNG-100 large-scale cosmological database, which are similar in their characteristics to the current physical parameters of the Milky Way, are used. With these time-varying potentials, we have reproduced the orbital trajectories of 143 GCs 10 Gyr back in time using our original phi-GPU N-body code. Each GC was treated as a single physical particle with the assigned position and velocity of the cluster center from the Gaia DR2 observations. For each of the potentials, 1000 initial conditions were generated with randomized initial velocities of GCs within the errors of the observational data. In this study, we consider close passages to be passages with a relative distance of less than 100 pc and a relative speed of less than 250 km/s. To select clusters that pass at close distances from the GalC, the following criterion is applied based only on the relative distance: it must be less than 100 pc. Applying the above criteria, the authors obtained statistically significant rates of close passages of GCs with respect to each other and to the GalC. It has been determined that GCs during their evolution have approximately 10 intersecting trajectories with each other on the average and approximately 3 to 4 close passages near the GalC in 1 Gyr at a distance of 50 pc for each of the chosen potentials.

Statistical analysis of the probability of globular clusters interactions with each other and with the galactic centre according to Gaia DR2 data on the cosmological time scale

Statistical analysis of the probability of globular clusters interactions with each other and with the galactic centre according to Gaia DR2 data on the cosmological time scale

Extremely Low-mass White Dwarf Stars Observed in Gaia DR2 and LAMOST DR8

We present the first results from our ongoing project to study extremely low-mass (ELM) white dwarfs (WDs) (M ≤ 0.3M ☉) with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) spectra. Based on the LAMOST DR8 spectral database, we analyzed 136 ELM WD candidates selected from Gaia DR2 data and 12 known objects previously identified by the ELM Survey. The atmospheric parameters and radial velocities of these stars were obtained by fitting the LAMOST low-resolution spectra. After comparing the atmospheric parameters of the 12 known objects from this work to the results reported by the ELM Survey, we demonstrated the potential of LAMOST spectra in probing into the nature of ELM WDs. Based on the atmospheric parameters and Gaia EDR3 data, we identified 21 new high-probability ELM WDs with masses M ≤ 0.3M ☉ and parallax estimates that agree to within a factor of 3. Two of them, J0338+4134 and J1129+4715, show significant radial velocity variability and are very likely to be binary systems containing at least one ELM WD.

Chemo-kinematics of the Milky Way spiral arms and bar resonances: Connection to ridges and moving groups in the solar vicinity

Making use of a new high-resolution spiral galaxy simulation as well as Gaia DR2 and EDR3 data complemented by chemical abundances from the Galah DR3, APOGEE DR16, and LAMOST DR5 surveys, we explore the possible link between the Milky Way (MW) spiral arms, (R, vϕ) ridges, and moving groups in local vR-vϕ space. We show that the tightly wound main spiral arms in the N-body simulation can be successfully identified using overdensities in angular momentum (AM) or guiding space and also in the distribution of dynamically cold stars close to their guiding centres. Stars in the AM overdensities that travel over many kiloparsec in radius trace extended density ridges in (R, vϕ) space and overdensities in the vR-vϕ plane of a solar neighbourhood (SNd)-like region, similar to those observed in the Gaia data. Similarly, the AM space of the MW contains several overdensities that correlate with a wave-like radial velocity pattern; this pattern is also reproduced by stars well beyond the SNd. We find that the fraction of Gaia stars located near their guiding centres shows three large-scale structures that approximately coincide with the MW spiral arms traced by distributions of maser sources in the Sagittarius, Local, and Perseus arms. This approach does not work for the Scutum arm near the end of the bar. Similar to the simulation, the stars in the AM overdensities follow the main (R, vϕ) density ridges with nearly constant angular momentum. When these ridges cross the SNd, they can be matched with the main vR-vϕ features. Thus we suggest that the Hat is the inner tail of the Perseus arm, one of the Hercules components is the Sagittarius arm, and the Arcturus stream is likely to be the outermost tail of the Scutum-Centaurus arm. Based on previous work, the bar corotation is suggested to coincide with the second, vϕ ≈ −55 km s−1 Hercules stream ridge, and the OLR with the Sirius stream. The latter is supported by a sharp decrease in mean metallicity beyond the Sirius stream, which is an expected behaviour of the OLR, limiting migration of the metal-rich stars from the inner MW. In various phase-space coordinates, the AM overdensity stars have a mean metallicity that is systematically higher by about 0.05 dex than the metallicity of the surrounding stars. This is a predicted behaviour of the spiral arms. We show that the wave-like metallicity pattern can be traced at least up to |z|≈1 kpc. It is linked to radial velocity variations seen even farther (|z|≈2 kpc) from the Galactic mid-plane.

Gaia-predicted brown dwarf detection rates around FGK stars in astrometry, radial velocity, and photometric transits

Context. After more than two decades of relevant radial velocity surveys, the current sample of known brown dwarfs (BDs) around FGK stars is only of the order of 100, limiting our understanding of their occurrence rate, properties, and formation. The ongoing ESA mission Gaia has already collected more than its nominal 5 years of mission data, and is expected to operate for up to 10 years in total. Its exquisite astrometric precision allows for the detection of (unseen) companions down to the Jupiter-mass level, allowing the efficient detection of large numbers of BDs. Additionally, its low-accuracy multi-epoch radial velocity measurements for GRVS < 12 can provide additional detections or constraints for the more massive BDs, while a further small sample will have detectable transits in Gaia photometry. Aims. Using detailed simulations, we provide an assessment of the number of BDs that could be discovered using Gaia astrometry, radial velocity, and photometric transits around main sequence (V) and subgiant (IV) FGK host stars for the nominal five-year and extended ten-year mission. Methods. Using a robust Δχ2 statistic we analyse the BD companion detectability from the Besançon Galaxy population synthesis model for G = 10.5 − 17.5 mag, complemented by Gaia DR2 data for G < 10.5, using the latest Gaia performance and scanning law, and literature-based BD-parameter distributions. Results. We report here only reliable detection numbers with Δχ2 > 50 for a five-year mission, and those in square brackets are for a ten-year mission. For astrometry alone, we expect 28 000–42 000 [45 000–55 000] detections out to several hundred parsecs [up to more than a kiloparsec]. The majority of these have G ∼ 14 − 15 [14 − 16] and periods of greater than 200 d, extending up to the longest simulated periods of 5 yr. Gaia radial velocity time-series for GRVS < 12 (G ≲ 12.7), should allow the detection of 830–1100 [1500–1900] BDs, most having orbital periods of < 10 days, and being amongst the most massive BDs (55 − 80MJ), though several tens will extend down to the ‘desert’ and lowest BD masses. Systems with at least three photometric transits with S/N > 3 are expected for 720–1100 [1400–2300] BDs, averaging at 4–5 [5–6] transits per source. The combination of astrometric and radial velocity detections should yield some 370–410 [870–950] detections. Perhaps 17–27 [35–56] BDs will have both transit and radial velocity detections, while both transits and astrometric detection will lead to a meagre 1–3 [4–6] detection(s). Conclusions. Though the above numbers are affected by ±50% uncertainty due to the uncertain occurrence rate and period distribution of BDs around FGK host stars, detections of BDs with Gaia will number in the tens of thousands, enlarging the current BD sample by at least two orders of magnitude, allowing us to investigate the BD fraction and orbital architectures as a function of host stellar parameters in greater detail than every before.

Astrometric identification of nearby binary stars II: Astrometric binaries in the Gaia Catalogue of Nearby Stars

Abstract We examine the capacity to identify binary systems from astrometric deviations alone. We apply our analysis to the Gaia eDR3 and DR2 data, specifically the Gaia Catalogue of Nearby Stars. We show we must renormalize (R)UWE over the local volume to avoid biasing local observations, giving a Local Unit Weight Error (LUWE). We use the simple criterion of LUWE>2, along with a handful of quality cuts to remove likely contaminants, to identify unresolved binary candidates. We identify 22,699 binary candidates within 100 pc of the Sun (just under 10 per cent of sources in this volume). We find an astrometric binary candidate fraction of around 20 per cent for giant stars, 10 per cent on the Main Sequence and lower than 1 per cent for White Dwarfs. We also look for Variability Induced Movers, by computing the correlation between photometric variability and astrometric noise - and show that VIMs may dominate the binary population of sub-Solar mass MS stars. We discuss the possibility and limitations of identifying non-luminous massive companions from astrometry alone, but find that our method is insensitive to these. Finally, we compare the astrometric deviations of MS binaries to the simulated sample from paper I, which show excellent agreement, and compute the astrometric candidate binary fraction as a function of absolute magnitude.

Discovery of Extended Structure Around Open Cluster COIN-Gaia 13 Based on Gaia EDR3

COIN-Gaia 13 is a newly discovered open cluster revealed by Gaia DR2 data. It is a nearby open cluster with a distance of about 513 pc. Combined with the five-dimensional astrometric data of Gaia EDR3 with higher accuracy, we use the membership assignment algorithm (pyUPMASK) to determine the membership of COIN-Gaia 13 in a large extended spatial region. The cluster has 478 identified candidate members. After obtaining reliable cluster members, we further study its basic properties and spatial distribution. Our results show that there is an obvious extended structure of the cluster in the X–Y plane. This elongated structure is distributed along the spiral arm, and the whole length is about 270 pc. The cluster age is 250 Myr, the total mass is about 439 M ⊙ and the tidal radius of the cluster is about 11 pc. Since more than half of member stars (352 stars) are located outside twice the tidal radius, it is suspected that this cluster is undergoing the dynamic dissolution process. Furthermore, the spatial distribution and kinematic analysis indicate that the extended structure in COIN-Gaia 13 is more likely to be caused by differential rotation of the Galaxy.

Age dissection of the vertical breathing motions in Gaia DR2: evidence for spiral driving

ABSTRACT Gaia DR2 has revealed breathing motions in the Milky Way, with stars on both sides of the Galactic mid-plane moving coherently towards or away from it. The generating mechanism of these breathing motions is thought to be spiral density waves. Here, we test this hypothesis. Using a self-consistent, high-resolution simulation with star formation, and which hosts prominent spirals, we first study the signatures of breathing motions excited by spirals. In the model, the breathing motions induced by the spiral structure have an increasing amplitude with distance from the mid-plane, pointing to an internal cause for them. We then show that, at fixed height, the breathing motion amplitude decreases with age. Next, we investigate the signature of the breathing motions in the Gaia DR2 data set. We demonstrate that, at the location with a consistently large breathing motion, the corresponding amplitude increases monotonically with distance from the mid-plane, in agreement with the model. Furthermore, we show that at the same location, the breathing motion amplitude decreases with age, again similar to what we find in the model. This strengthens the case that the observed breathing motions are driven by spiral density waves.

Collision of two stellar associations in the nearby Gum Nebula

ABSTRACT Based on Gaia DR2 data and new CHIRON radial velocities, we have discovered that two nearby stellar associations UPK 535 (318.08 ± 0.29 pc, $25^{+15}_{-10}$ Myr, 174 stars) and Yep 3 (339.54 ± 0.25 pc, $45^{+55}_{-20}$ Myr, 297 stars) in the Gum Nebula have recently collided. We project stars’ current positions, motions, and measurement uncertainties backward and forward through time in a 10 000-trial Monte Carlo simulation. On average, the associations’ centres of mass come within 18.89 ± 0.73 pc of each other 0.84 ± 0.03 Myr ago. A mode of 54 ± 7 close (<1 pc) stellar encounters occur during the collision. We cannot predict specific star–star close encounters with our current ∼7.6 pc distance precision and 21.5 per cent complete radial velocity sample. Never the less, we find that two stars in UPK 535 and two stars in Yep 3 undergo a nonspecific close encounter in >70 per cent of trials and multiple close encounters in ∼30 per cent. On average, the closest approach of any two stars is 0.13 ± 0.06 pc, or 27 000 ± 12 000 au. With impulse-tracing values up to $2.7^{+3.1}_{-1.1}$ M⊙ pc−2 km−1 s, such close encounters could perturb stars’ Oort cloud comets (if present), cause heavy bombardment events for exoplanets (if present), and reshape Solar system architectures. Finally, an expansion of our simulation suggests other associations in the region are also interacting. Association collisions may be commonplace, at least in the Gum Nebula straddling the Galactic plane, and may spur Solar system evolution more than previously recognized.

Kinematic characteristics of the Milky Way globular clusters based on Gaia DR-2 data

Using the data from Gaia (ESA) Data Release 2 we performed the orbital calculations of globular clusters (GCs) of the Milky Way. To explore possible close encounters (or collisions) between the GCs, using our own developed high-order phi-GRAPE code, we integrated (backward and forward) the orbits of 119 objects with reliable positions and proper motions. In calculations, we adopted a realistic axisymmetric Galactic potential (bulge + disk + halo). Using different impact conditions, we found four pairs of the six GCs that may have experienced an encounter within twice the sum of the half-mass radii (collisions) over the last 5Gyr: Terzan3 - NGC 6553, Terzan 3 - NGC 6218, Liller 1 - NGC 6522 and Djorg 2 - NGC 6553.

Kinematic characteristics of the Milky Way globular clusters based on Gaia DR2 data

Using the data from Gaia (ESA) Data Release 2 we performed the orbital calculations of globular clusters (GCs) of the Milky Way. To explore possible close encounters (or collisions) between the GCs, using our own developed high-order φ-GRAPE code, we integrated backward and forward orbits of 119 objects with reliable positions and proper motions. In the calculations, we adopted a realistic axisymmetric Galactic potential (bulge + disk + halo). Using different impact conditions, we found four pairs of six GCs that may have experienced an encounter within twice the sum of the half-mass radii ('collisions') over the last 5 Gyr: Terzan 3 — NGC 6553, Terzan 3 — NGC 6218, Liller 1 — NGC 6522 and Djorg 2 — NGC 6553.

Kinematic characteristics of the Milky Way globular clusters based on Gaia DR2 data

Using the data from Gaia (ESA) Data Release 2 we performed the orbital calculations of globular clusters (GCs) of the Milky Way. To explore possible close encounters (or collisions) between the GCs, using our own developed high-order φ-GRAPE code, we integrated backward and forward orbits of 119 objects with reliable positions and proper motions. In the calculations, we adopted a realistic axisymmetric Galactic potential (bulge + disk + halo). Using different impact conditions, we found four pairs of six GCs that may have experienced an encounter within twice the sum of the half-mass radii ('collisions') over the last 5 Gyr: Terzan 3 — NGC 6553, Terzan 3 — NGC 6218, Liller 1 — NGC 6522 and Djorg 2 — NGC 6553.

High Mass-Ratio Binary Population in Open Clusters: Segregation of Early Type Binaries and an Increasing Binary Fraction with Mass

Abstract Binary stars play a vital role in astrophysical research, as a good fraction of stars are in binaries. Binary fraction (BF) is known to change with stellar mass in the Galactic field, but such studies in clusters require binary identification and membership information. Here, we estimate the total and spectral-type high-mass-ratio (HMR) BF (f 0.6) in 23 open clusters using unresolved binaries in color–magnitude diagrams using Gaia DR2 data. We introduce the segregation index (   ) parameter to trace mass segregation of HMR (total and mass) binaries and the reference population. This study finds that in open clusters, (1) HMR BF for the mass range 0.4–3.6 M ⊙ (early M to late B-type stars) has a range of 0.12–0.38 with a peak at 0.12–0.20; (2) older clusters have a relatively higher HMR BF; (3) the mass-ratio distribution is unlikely to be a flat distribution and BF (total) ∼(1.5–2.5) × f 0.6; (4) a decreasing BF (total) from late B to K-type stars, in agreement with the Galactic field stars; (5) older clusters show radial segregation of HMR binaries; (6) B-type and A–F type HMR binaries show radial segregation in some young clusters suggesting a primordial origin. This study will constrain the initial conditions and identify the major mechanisms that regulate binary formation in clusters. Primordial segregation of HMR binaries could result from massive clumps spatially segregated in the collapse phase of the molecular cloud.

Milky Way total mass derived by rotation curve and globular cluster kinematics from Gaia EDR3

ABSTRACT Using action-based distribution function for the dynamical model of the Milky Way (MW) we have estimated its total mass and its density profile. Constraints are coming from the globular cluster proper motions from Gaia EDR3, from the rotation curve based on Gaia DR2 data, and from the vertical force data. We use Bayesian Markov chain Monte Carlo method to explore the parameters, for which the globular cluster distribution function and the Galactic potential are fully constrained. Numerical simulations are used to study the uncertainties on the potential constraint if considering a possible massive Large Magellanic Cloud (LMC). We found that a massive LMC (1.5 × 1011 M⊙) will affect the MW mass measurement at large radius, which includes both the MW and the LMC. We also use the FIRE2 Latte cosmological hydrodynamic simulations to make mock data set from an MW-like galaxy that includes many unrelaxed substructures. We test the effect of these unrelaxed substructures on the final results, and found that the measured rotation curve fluctuated around input value within 5 per cent. By keeping a large freedom in choosing a priori mass profile for both baryonic and dark matter leads a total mass of the MW that ranges from $5.36_{-0.68}^{+0.81}\times 10^{11}$ M⊙ to $7.84_{-1.97}^{+3.08} \times 10^{11}$ M⊙. This includes the contribution of a putative massive LMC and significantly narrows the MW total mass range published earlier. Such total mass leads to dark matter density at solar position of $0.34_{-0.02}^{+0.02}$ GeV cm−3.

Determination of dynamical ages of open clusters through the A+ parameter – I

ABSTRACT The sedimentation level of blue straggler stars (BSS) has been shown to be a great tool to investigate the dynamical states of globular clusters (GCs). The area enclosed between the cumulative radial distributions of BSS and a reference population up to the half-mass radius of the clusters, $A^+_{\mathrm{rh}}$, is known to be a measure of the sedimentation of BSS in GCs. In this work, we calculate $A^+_{\mathrm{rh}}$ for 11 open clusters (OCs) using a combined list of main-sequence turn-off stars, sub-giant branch stars, and red giant branch stars as reference population. The BSS, the reference populations, and the cluster members are identified using the proper motions and parallaxes from the Gaia DR2 data. In a subset of clusters, the BSS are confirmed cluster members on the basis of radial velocity information available in the literature. Using the Pearson and Spearman rank correlation coefficients, we find weak correlations between the estimated values of $A^+_{\mathrm{rh}}$ and other markers of dynamical ages of the clusters, i.e. the number of central relaxations a cluster has experienced since its formation, and the structural parameters of the clusters. Based on statistical tests, we find that these correlations are similar to the corresponding correlations among the less evolved GCs, albeit within large errors.

Star formation around three co-moving HAeBe stars in the Cepheus Flare

Context. The presence of three more Herbig Ae/Be (HAeBe) candidates in the Cepheus Flare within a 1.5° radius centered on HD 200775 suggests that star formation is prevalent in a wider region of the LDN 1147/1158, LDN 1172/1174, and LDN 1177 clouds. A number of young stellar objects (YSOs) are found to be distributed toward these cloud complexes along with the HAeBe stars. Various star formation studies clearly indicate ongoing low-mass star formation inside the clouds of this region. Sources associated with less near-infrared excess and less Hα emission raise the possibility that more low-mass YSOs, which were not identified in previous studies, are present in this region. Aims. The aim is to conduct a search for additional young sources that are kinematically associated with the previously known YSOs and to characterize their properties. Methods. Based on the Gaia DR2 distances and proper motions, we found that the HAeBe candidates BD+68°1118, HD 200775, and PV Cep are all spatially and kinematically associated with previously known YSOs. Based on the Gaia DR2 data, we identified a number of co-moving sources around BD+68°1118. These sources are characterized using optical and near-infrared color-color and color-magnitude diagrams. Results. We estimated a distance of 340 ± 7 pc to the whole association that contains BD+68°1118, HD 200775, and PV Cep. Based on the distance and proper motions of all the known YSOs, a total of 74 additional co-moving sources are found in this region, of which 39 form a loose association surrounding BD+68°1118. These sources are predominantly M-type sources with ages of ∼10 Myr and no or very little near-infrared excess emission. The distribution of co-moving sources around BD+68°1118 is much more scattered than that of sources found around HD 200775. The positive expansion coefficients obtained via the projected internal motions of the sources surrounding BD+68°1118 and HD 200775 show that the co-moving sources are in a state of expansion with respect to their HAeBe stars. A spatio-temporal gradient of these sources toward the center of the Cepheus Flare Shell supports the concept of star formation triggered by external impacts.

The infrared excess emission from nearby Gaia DR2 M dwarfs

ABSTRACT We use Gaia DR2 data to search for M dwarfs with infrared (IR) excess, within 100 pc. By cross-matching Gaia with AllWISE and 2MASS catalogues, we select a subset of K/M dwarfs with reliable photometric data in both the optical and near-to-mid IR. Using our SED fitting pipeline, we determine a photospheric model for each star and determine its significance of excess (SOE) inWISE passbands W3 and W4, which is used to classify potential IR excess. Through exhaustive vetting procedures, we present 37 new late-type IR-excess candidates, most of them M dwarfs, along with analyses of 12 previously known IR-excess stars. We group our candidates into two categories based on their SOE and likelihood of contamination. We also perform an isochronal age analysis as well as a moving group membership analysis, and discover six potential moving group members belonging to β Pictoris, Argus, Carina, Columba, and Tucana/Horologium Moving Groups. We conclude with a discussion of the nature of IR excess around late-type stars.