A Young Cluster With an Extended Main Sequence Turnoff: Confirmation of a Prediction of the Stellar Rotation Scenario

Abstract

We present Hubble Space Telescope photometry of NGC1850, a ~100 Myr, ~10^5 Msun cluster in the Large Magellanic Cloud. The colour magnitude diagram clearly shows the presence of an extended main sequence turnoff (eMSTO). The use of non-rotating stellar isochrones leads to an age spread of ~40 Myr. This is in good agreement with the age range expected when the effects of rotation in MSTO stars are wrongly interpreted in terms of age spread. We also do not find evidence for multiple, isolated episodes of star-formation bursts within the cluster, in contradiction to scenarios that invoke actual age spreads to explain the eMSTO phenomenon. NGC 1850 therefore continues the trend of eMSTO clusters where the inferred age spread is proportional to the age of the cluster. While our results confirm a key prediction of the scenario where stellar rotation causes the eMSTO feature, direct measurements of the rotational rate of MSTO stars is required to definitively confirm or refute whether stellar rotation is the origin of the eMSTO phenomenon or if it is due to an as yet undiscovered effect.

arXiv commentMNRAS letters, in press

References in corpus (40)

• Grids of stellar models with rotation - I. Models from 0.8 to 120 Msun at solar metallicity (Z = 0.014)
• A large stellar evolution database for population synthesis studies. I. Scaled solar models and isochrones
• Resolved Massive Star Clusters in the Milky Way and its Satellites: Brightness Profiles and a Catalogue of Fundamental Parameters
• A large stellar evolution database for population synthesis studies. II. Stellar models and isochrones for an alpha-enhanced metal distribution
• The ACS Survey of Galactic Globular Clusters. XII. Photometric Binaries along the Main-Sequence
• A Stellar Rotation Census of B Stars: from ZAMS to TAMS
• New Limits on an Intermediate Mass Black Hole in Omega Centauri: I. Hubble Space Telescope Photometry and Proper Motions
• The Effect of Stellar Rotation on Colour-Magnitude Diagrams: On the apparent presence of multiple populations in intermediate age stellar clusters
• A double main sequence turn-off in the rich star cluster NGC 1846 in the Large Magellanic Cloud
• Astrometry and photometry with HST WFC3. II. Improved geometric-distortion corrections for 10 filters of the UVIS channel
• A Method for Determining the Star Formation History of a Mixed Stellar Population
• Multiple stellar populations in three rich Large Magellanic Cloud star clusters
• Multiple stellar populations in Magellanic Clouds clusters. I. An ordinary feature for intermediate age globulars in the LMC?
• On the Formation of Multiple Stellar Populations in Globular Clusters
• The Age and Age Spread of the Praesepe and Hyades Clusters: a Consistent, ~800 Myr Picture from Rotating Stellar Models
• Studying the YMC population of M83: how long clusters remain embedded, their interaction with the ISM and implications for GC formation theories
• Extended Main Sequence Turnoffs in Intermediate-Age Star Clusters: A Correlation Between Turnoff Width and Early Escape Velocity
• Populations of rotating stars. - I. Models from 1.7 to 15 Msun at Z = 0.014, 0.006, and 0.002 with Ω/Ωcrit between 0 and 1
• Populations of rotating stars III. SYCLIST, the new Geneva Population Synthesis code
• Constraining Globular Cluster Formation Through Studies of Young Massive Clusters: I. A lack of ongoing star formation within young clusters
• Apparent Age Spreads in Clusters and the Role of Stellar Rotation
• Multiple stellar populations in Magellanic Cloud clusters. III. The first evidence of an extended main sequence turn-off in a young cluster: NGC1856
• Rotating Stellar Models Can Account for the Extended Main Sequence Turnoffs in Intermediate Age Clusters
• The extended Main Sequence Turn Off cluster NGC1856: rotational evolution in a coeval stellar ensemble
• Can rotation explain the multiple main sequence turn-offs of Magellanic Cloud star clusters?
• No Evidence for Significant Age Spreads in Young Massive LMC Clusters
• Constraining globular cluster formation through studies of young massive clusters - II. A Single Stellar Population Young Massive Cluster in NGC 34
• No evidence of chemical anomalies in the bimodal turnoff cluster NGC 1806 in the LMC
• The exclusion of a significant range of ages in a massive star cluster
• Constraining globular cluster formation through studies of young massive clusters - V. ALMA observations of clusters in the Antennae
• Constraining Globular Cluster Formation Through Studies of Young Massive Clusters - IV. Testing the Fast Rotating Massive Star Scenario
• Constraining globular cluster formation through studies of young massive clusters - III. A lack of gas and dust in massive stellar clusters in the LMC and SMC
• Controversial Age Spreads from the Main Sequence Turn-Off and Red Clump in Intermediate-Age Clusters in the LMC
• Is the Escape Velocity in Star Clusters Linked to Extended Star Formation Histories? Using NGC 7252: W3 as a Test Case
• The Morphology of the Sub-Giant Branch and Red Clump Reveal No Sign of Age Spreads in Intermediate Age Clusters
• On the Interpretation of Sub-Giant Branch Morphologies of Intermediate-Age Star Clusters with Extended Main Sequence Turnoffs
• The star formation history of the Large Magellanic Cloud star clusters NGC1846 and NGC1783
• New Constraints on the Star Formation History of the Star Cluster NGC 1856
• Dynamics of the Young Binary LMC Cluster NGC 1850
• Heart of Darkness: dust obscuration of the central stellar component in globular clusters younger than ~100Myr in multiple stellar population models

Cited by in corpus (45)

• Age as a Major Factor in the Onset of Multiple Populations in Stellar Clusters
• Multiple stellar populations in Magellanic Cloud clusters. IV. The double main sequence of the young cluster NGC1755
• Extended Main Sequence Turnoffs in Open Clusters as Seen by Gaia: I. NGC 2818 and the Role of Stellar Rotation
• NGC 1866: First Spectroscopic Detection of Fast Rotating Stars in a Young LMC Cluster
• A high fraction of Be stars in young massive clusters: evidence for a large population of near-critically rotating stars
• Multiple stellar populations in Magellanic Cloud clusters. V. The split main sequence of the young cluster NGC1866
• The search for multiple populations in Magellanic Cloud Clusters IV: Coeval multiple stellar populations in the young star cluster NGC 1978
• The Search for Multiple Populations in Magellanic Cloud Clusters III: No evidence for Multiple Populations in the SMC cluster NGC 419
• The search for multiple populations in Magellanic Clouds clusters - V. Correlation between cluster age and abundance spreads
• A black hole detected in the young massive LMC cluster NGC 1850
• Extended Main Sequence Turnoffs in Intermediate-Age Star Clusters: Stellar Rotation diminishes, but does not eliminate, Age Spreads
• Combined Effects of Rotation and Age Spreads on Extended Main Sequence Turn Offs
• Discovery of Extended Main Sequence Turn-offs in Four Young Massive Clusters in the Magellanic Clouds
• The formation of secondary stellar generations in massive young star clusters from rapidly cooling shocked stellar winds
• Discrepancies in the ages of young star clusters; evidence for mergers?
• Li Evolution and the Open Cluster NGC 6819: A Correlation Between Li Depletion and Spindown in Dwarfs More Massive Than the F-Dwarf Li-Dip
• Disappearance of the extended main sequence turn-off in intermediate age clusters as a consequence of magnetic braking
• Spectroscopic detection of multiple populations in the ~2 Gyr old cluster Hodge 6 in the LMC
• Isochrone-cloud fitting of the extended Main-Sequence Turn-Off of young clusters
• Asteroseismology of the young open cluster NGC 2516 I: Photometric and spectroscopic observations
• Young LMC clusters: the role of red supergiants and multiple stellar populations in their integrated light and CMDs
• Metallicities and ages for star clusters and their surrounding fields in the Large Magellanic Cloud
• Observational hints of a real age spread in the young LMC star cluster NGC 1971
• A New Approach to Convective Core Overshooting: Probabilistic Constraints from Color-Magnitude Diagrams of LMC Clusters
• The radial distributions of the two main-sequence components in the young massive star cluster NGC 1856
• The effects of the overshooting of the convective core on main-sequence turnoffs of young- and intermediate-age star clusters
• Should I Stay or Should I Go: Stellar Wind Retention and Expulsion in Massive Star Clusters
• On the origin of UV-dim stars: a population of rapidly rotating shell stars?
• An Analysis of the Population of Extended Main Sequence Turn-off Clusters in the Large Magellanic Cloud
• Accretion of sub-stellar companions as the origin of chemical abundance inhomogeneities in globular clusters
• Stellar populations in star clusters
• On the Precision of Full-spectrum Fitting of Simple Stellar Populations. I. Well-sampled Populations
• New insights into the formation of the blue main sequence in NGC 1850
• The spatial distributions of blue main-sequence stars in Magellanic Cloud star clusters
• Discovery and Characterization of a Rare Magnetic Hybrid $\beta$ Cephei Slowly Pulsating B-type Star in an Eclipsing Binary in the Young Open Cluster NGC 6193
• On the Precision of Full-Spectrum Fitting of Simple Stellar Populations. IV. A Systematic Comparison with Results from Colour-Magnitude Diagrams
• The Effects of Binary Stars on the Color-Magnitude Diagrams of Young-Age Massive Star Clusters
• MUSE spectroscopic observations of the Young Massive Cluster NGC1850
• At what mass are stars braked? The implication from the turnoff morphology of NGC 6819
• Extended Main-Sequence Turnoff and Red Clump in intermediate-age star clusters: A study of NGC 419
• Extended Main Sequences in Star Clusters
• NGC 1850 BH1 is another stripped-star binary masquerading as a black hole
• The He abundance in NGC 1850 A and B: are we observing the early stage of formation of multiple populations in a stellar cluster?
• The Predicted Properties of Helium-Enriched Globular Cluster Progenitors at High Redshift
• Hubble Space Telescope proper motions of Large Magellanic Cloud star clusters -- II. Kinematic structure of young and intermediate-age clusters