Protoplanetary discs around sun-like stars appear to live longer when the metallicity is low
arXiv:2412.10361 · doi:10.3847/1538-4357/ad7a63
Abstract
Previous Hubble Space Telescope (HST) observations of the star-forming cluster NGC 346 in the Small Magellanic Cloud (SMC) had revealed a large population of pre-main sequence (PMS) candidates, characterised by Halpha excess emission in their photometry. However, without access to spectroscopy, the nature of these objects remained unclear. Using the NIRSpec instrument on board JWST, we studied a sample of these stars, with masses in the range ~0.9-1.8 Msun, effective temperatures in the range 4,500-8,000 K, and PMS ages between ~0.1 and 30 Myr. Here we present the first spectra of solar-mass PMS stars in the metal-poor SMC (Z=1/8 Zsun) and discuss the physical properties of ten representative sources with good signal-to-noise ratio. The observations indicate that even the oldest of these PMS candidates are still accreting gas with typical rates of ~10^{-8} Msun/yr for stars older than ~10 Myr, confirming their PMS nature. The spectra also reveal near-infrared excess and molecular hydrogen excitation lines consistent with the presence of discs around these stars. These findings suggest that in a low-metallicity environment circumstellar discs can live longer than previously thought.
arXiv comment17 pages, 7 figures, to be published in The Astrophysical Journal, Vol 977, Article 214
References in corpus (67)
- PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
- Correcting for the Effects of Interstellar Extinction
- A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
- High Redshift Galaxies in the Hubble Deep Field. Color Selection and Star Formation History to z=4
- MESA Isochrones and Stellar Tracks (MIST) 0: Methods for the construction of stellar isochrones
- Disk Frequencies and Lifetimes in Young Clusters
- The NextGen Model Atmosphere grid for $3000\le \Teff \le 10000\K$
- New PARSEC evolutionary tracks of massive stars at low metallicity: testing canonical stellar evolution in nearby star forming dwarf galaxies
- X-Shooter spectroscopy of young stellar objects in Lupus: Accretion properties of class II and transitional objects
- An Optical Spectroscopic Study of T Tauri Stars. I. Photospheric Properties
- Timescale of Mass Accretion in Pre-Main-Sequence Stars
- X-Shooter spectroscopy of young stellar objects: IV -- Accretion in low-mass stars and sub-stellar objects in Lupus
- The Physics of Star Formation
- The Pisa pre-main sequence tracks and isochrones. A database covering a wide range of Z, Y, mass, and age values
- A Young White Dwarf Companion to Pulsar 1620-26: Evidence for Early Planet Formation
- Episodic accretion at early stages of evolution of low mass stars and brown dwarfs: a solution for the observed luminosity spread in HR diagrams?
- A Spitzer view of protoplanetary disks in the gamma Velorum cluster
- Bump Cepheids in the Magellanic Clouds: Metallicities, the Distances to the LMC and SMC, and the Pulsation-Evolution Mass Discrepancy
- Effect of episodic accretion on the structure and the lithium depletion of low-mass stars and planet-hosting stars
- The Near-Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope II. Multi-object spectroscopy (MOS)
- Reconciling the local galaxy population with damped Ly-alpha cross sections and metal abundances
- X-ray irradiated protoplanetary disk atmospheres I: Predicted emission line spectrum and photoevaporation
- Probing Cosmic Chemical Evolution with Gamma-Ray Bursts: GRB060206 at z=4.048
- X-ray irradiated protoplanetary disk atmospheres II: Predictions from models in hydrostatic equilibrium
- Mapping accretion and its variability in the young open cluster NGC 2264: a study based on u-band photometry
- Circumstellar Disk Lifetimes In Numerous Galactic Young Stellar Clusters
- Evolution of protoplanetary disks from their taxonomy in scattered light: spirals, rings, cavities, and shadows
- The VLT-FLAMES Tarantula Survey XVI. The optical+NIR extinction laws in 30 Doradus and the photometric determination of the effective temperatures of OB stars
- Past and present star formation in the SMC: NGC 346 and its neighborhood
- Episodic accretion: the interplay of infall and disc instabilities
- X-Shooter spectroscopy of young stellar objects in Lupus. Atmospheric parameters, membership and activity diagnostics
- Measuring tiny mass accretion rates onto young brown dwarfs
- The Lifetime of Protoplanetary Disks in a Low-Metallicity Environment
- The First Planets: the Critical Metallicity for Planet Formation
- Photometric determination of the mass accretion rates of pre-main sequence stars. I. Method and application to the SN1987A field
- Protoplanetary Disk Sizes and Angular Momentum Transport
- A Planet in a 0.6-AU Orbit Around the K0 Giant HD 102272
- Short Lifetime of Protoplanetary Disks in Low-metallicity Environments
- Photometric determination of the mass accretion rates of pre-main sequence stars. II. NGC346 in the Small Magellanic Cloud
- Self-consistent evolution of accreting low-mass stars and brown dwarfs
- Discovery of a Large Stellar Periphery Around the Small Magellanic Cloud
- A Giant Planet Around a Metal-poor Star of Extragalactic Origin
- NGC 346 in the Small Magellanic Cloud. III. Recent Star Formation and Stellar Clustering Properties in the Bright HII Region N 66
- Hubble Tarantula Treasury Project. IV. The extinction law
- Unveiling extremely veiled T Tauri stars
- GIARPS High-resolution Observations of T Tauri stars (GHOsT). IV. Accretion properties of the Taurus-Auriga young association
- The effect of episodic accretion on the phase transition of CO and CO_2 in low-mass star formation
- The extinction law inside the 30 Doradus nebula
- Photometric determination of the mass accretion rate of pre-main sequence stars. IV. Recent star formation in NGC 602
- Clues to the star formation in NGC 346 across time and space
- The Small Magellanic Cloud Investigation of Dust and Gas Evolution (SMIDGE): The Dust Extinction Curve from Red Clump Stars
- GIARPS High-resolution Observations of T Tauri stars (GHOsT). III. A pilot study of stellar and accretion properties
- Photometric determination of the mass accretion rates of pre-main sequence stars. V. Recent star formation in the 30 Dor nebula
- Pre-Main Sequence stars in the star forming complex Sh 2-284
- The Near-Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope V. Optimal algorithms for planning multi-object spectroscopic observations
- VAMDC as a Resource for Atomic and Molecular Data and the New Release of VALD
- Low-metallicity Young Clusters in the Outer Galaxy I. Sh 2-207
- Near-IR Molecular Hydrogen Emission of Protostars: Probing Circumstellar Environments
- Dispersal timescale of protoplanetary disks in the low-metallicity young cluster Dolidze 25
- Extending the extinction law in 30 Doradus to the infrared with JWST
- Photometric determination of the mass accretion rates of pre-main sequence stars. VI. The case of LH 95 in the Large Magellanic Cloud
- Crossing the Gould Belt in the Orion vicinity
- Determining stellar accretion rates from and emission lines with JWST NIRSpec
- Photometric determination of the mass accretion rates of pre-main-sequence stars. VIII. Recent star formation in NGC 299
- The internal proper motion kinematics of NGC346: past formation and future evolution
- Photometric determination of the mass accretion rates of pre-main sequence stars. VII. The low-density cluster NGC 376 in the Small Magellanic Cloud
- Pre-main Sequence stars in LH91