Pith. sign in

REVIEW 2 major objections 4 minor 131 references

Disk-bearing young stars in the metal-poor Sh2-284 region accrete gas at rates comparable to those in solar-metallicity star-forming regions, with tentative evidence that the emission-line scaling relations used to measure accretion may dep

Reviewed by Pith at T0; open to challenge. T0 means a machine referee read the full paper against a public rubric. the ladder, T0–T4 →

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗

T0 review · deepseek-v4-flash

2026-08-01 04:24 UTC pith:TRNT5KSU

load-bearing objection Useful wide-field accretion census of a metal-poor region, with an honest calibration caveat — but the abstract oversells a flattening that the body itself says is not statistically significant. the 2 major comments →

arxiv 2607.22533 v1 pith:TRNT5KSU submitted 2026-07-24 astro-ph.GA astro-ph.SR

LBT-MODS spectroscopy of young stellar objects in the distant metal-poor star forming region Sh2-284: Stellar and accretion properties

Katia Biazzo , Juan Manuel Alcal\'a , Felice Cusano , Mario Guarcello , Diego Paris , Ester Marini , Roberta Carini , Teresa Giannini
show 4 more authors
Brunella Nisini Simone Antoniucci Guido De Marchi Maria Gabriela Navarro Ovando
This is my paper
classification astro-ph.GA astro-ph.SR
keywords young stellar objectsaccretionstar-forming regionsmetallicitySh2-284Dolidze 25emission-line diagnosticsmass accretion rate
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

This paper reports the first wide-field spectroscopic census of young stellar objects (YSOs) in Sh2-284, a star-forming complex in the outer Milky Way with roughly one-third solar metallicity. It finds that the 68 disk-bearing stars observed with LBT/MODS are actively accreting gas from their disks at rates that are statistically indistinguishable from those measured in solar-metallicity regions like Lupus, with a median rate of about 2.2×10⁻⁸ solar masses per year. The authors also present a cross-checked but tentative trend: the flux-flux relations linking H-alpha to other accretion tracers (H-beta, H-gamma, the CaII infrared triplet, and Paschen lines) appear shallower than in Lupus, hinting that the emission-line ratios themselves may shift with metallicity. If confirmed, this would show that gas accretion can proceed efficiently in metal-poor environments and that accretion diagnostics calibrated only at solar metallicity may need revision for low-metallicity systems.

Core claim

In the metal-poor (Z~1/3 Zsun) star-forming complex Sh2-284, the paper measures stellar and accretion properties of 68 YSOs across a 45 arcmin by 45 arcmin field, using nine emission-line tracers. The derived mass accretion rates span from about 2.3×10⁻¹⁰ to 1.0×10⁻⁶ solar masses per year, with a median of roughly 2.2×10⁻⁸ solar masses per year, statistically overlapping with solar-metallicity samples when masses and ages are matched. The central new claim is a tentative flattening of the flux-flux relations (H-alpha versus H-beta, H-gamma, CaII infrared triplet, and Paschen lines) relative to solar-metallicity regions, interpreted as evidence that the thermal and ionization structure of the

What carries the argument

The analysis rests on the magnetospheric accretion paradigm: line luminosities from accreting gas are converted to accretion luminosity using empirical L_line-L_acc relations calibrated in Lupus, then to mass accretion rate via the free-fall relation Mdot = 1.25 L_acc R*/GM*, adopting an inner disk truncation radius of five stellar radii. The multi-tracer approach—Balmer, CaII, and Paschen lines observed simultaneously—serves as an internal consistency check and is the basis for the flux-flux slope comparison with Lupus.

Load-bearing premise

The conclusion that accretion rates are normal in metal-poor Sh2-284 assumes that the relationship between hydrogen-line luminosity and accretion luminosity, calibrated in solar-metallicity Lupus, is unchanged when the gas has one-third the metal content.

What would settle it

Measure accretion luminosity for a subset of Sh2-284 YSOs through U-band excess continuum veiling, independently of the line-luminosity relations; if the continuum-based L_acc disagrees systematically with the H-alpha-based values as metallicity changes, the invariance assumption fails. Alternatively, a sample of several hundred YSOs with the same multi-tracer observations would narrow the error bars on the flux-flux slopes enough to test whether they truly converge to Lupus values.

Watch this falsifier — get emailed when new claim-graph text bears on it.

If this is right

  • Gas accretion persists at normal levels in sub-solar metallicity environments, countering suggestions that low-metallicity disks dissipate too quickly to sustain accretion.
  • If the flux-flux flattening is real, line-based accretion diagnostics calibrated at solar metallicity will systematically misestimate accretion rates in metal-poor regions, affecting JWST and other surveys of low-Z star formation.
  • Disk-bearing stars in Sh2-284 at ages of about 1–2 Myr still accrete, consistent with dust-based disk fractions and indicating that planet-forming gas reservoirs remain available in low-metallicity disks.
  • The ratio of Balmer to CaII/Paschen emission may become a metallicity-sensitive probe of accretion flows in future spectroscopic surveys.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • A concrete testable extension is to combine the Sh2-284 spectra with U-band excess (continuum veiling) measurements to check whether the L_acc scale itself depends on metallicity, independently of the line-luminosity calibrations.
  • If the flattening is genuine, the H-alpha/H-beta flux ratio in metal-poor accretors should correlate with iron abundance within a single region; surveying additional outer-Galactic clouds could reveal a monotonic trend with Z.
  • The paper's matched-mass comparison suggests that intrinsic scatter in accretion rate at fixed stellar mass is dominated by factors other than metallicity, so isolating metallicity effects will require larger, homogeneous samples with matched ages.
  • The outer Galaxy may serve as a bridge between local solar-metallicity regions and Magellanic Cloud metallicities, so expanding the sample to more anticenter clouds could turn the tentative trend into a quantitative scaling law.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit.

Referee Report

2 major / 4 minor

Summary. The paper presents LBT-MODS spectroscopy of 68 YSO candidates in Sh2-284, a metal-poor (Z ~ 1/3 Z_sun) star-forming region at ~4.7 kpc toward the Galactic anticenter. Using up to nine emission-line accretion diagnostics (Hα, Hβ, Hγ, Ca II IRT, Paη, Paζ, Paε), the authors derive stellar parameters, extinction-corrected line fluxes, accretion luminosities, and mass accretion rates. They report a median Mdot of ~2.2e-8 Msun/yr, spanning ~2.3e-10 to ~1.0e-6 Msun/yr, and compare their sample with solar-metallicity and low-metallicity regions (Lupus, NGC 3603, NGC 346, Dolidze 25). They also present tentative evidence that the flux–flux relations between Hα and other lines are flatter in Sh2-284 than in Lupus, which they interpret as a possible metallicity-dependent behavior of accretion diagnostics.

Significance. If the results hold, this is the first wide-field spectroscopic census of accretion in a Galactic low-metallicity region, bridging nearby solar-metallicity studies and extragalactic JWST programs. The paper has notable strengths: a multi-diagnostic approach with internal cross-checks (Sect. 3.3), proper-motion filtering (Sect. 3.1.1), photometric flux anchoring of the spectra (Sect. 2.3.2), and consistency checks against previous measurements by Kalari & Vink (2015) and Ashraf et al. (2026). The tentative flattening of the flux–flux relations, if confirmed, would have direct implications for the use of solar-metallicity calibrations in low-Z environments. However, the absolute accretion scale and the cross-metallicity comparison rest on the empirical L_line–L_acc calibrations of Alcalá et al. (2017), calibrated in Lupus at solar metallicity; the paper explicitly acknowledges this but does not quantify how a metallicity-dependent shift would affect the conclusions. The flattening claim is also based on small samples (4–16 sources per diagnostic) and is statistically weak for several lines.

major comments (2)
  1. [Sect. 4.1, Eqs. (2)–(9), Sect. 2.1] The central conclusion that accretion rates in Sh2-284 are comparable to solar-metallicity regions (median ~2.2e-8 Msun/yr, Sect. 3.4 and Fig. 15) relies entirely on the Alcalá et al. (2017) L_line–L_acc calibrations derived in Lupus. The paper acknowledges this in Sect. 3.3 ('does not constitute an independent validation of our absolute accretion scale') and Sect. 3.5 ('both methods rely on empirical calibrations... may mask subtle chemical dependencies'), but no quantitative estimate is given for how large a metallicity-dependent correction could be. This is not an internal inconsistency, but it is load-bearing: if the accretion column in Z~1/3 Z_sun gas cools or ionizes differently, the absolute Mdot values and the Fig. 15 comparison with solar-metallicity samples would shift. The paper's own tentative finding of flatter flux–flux relations (Sect. 4.1) suggests that line ratios do dep
  2. [Sect. 4.1] The flux–flux slopes (Sect. 4.1) are derived from a sample that was pre-selected on Hα excess (Sect. 2.1: IPHAS Hα excess criterion and R-band magnitude range). This selection truncates the observed Hα distribution at the low-flux end, which can bias the fitted slope of log FHα versus log F_line even if the underlying relation is universal. The paper does not address this selection effect. Because the flattening is the main new physical claim (even if hedged as tentative), the authors should quantify the bias. Concretely, simulate Lupus-like flux–flux relations with the same intrinsic scatter, apply the selection thresholds used here (Hα excess, R range, line detectability), and show how much the fitted slopes are expected to shift. This is important for the Ca II and Paschen diagnostics, where the claimed difference from Lupus appears largest but the sample sizes are only 4–13 sources.
minor comments (4)
  1. [Sect. 3.4] The reporting of the central accretion rate is inconsistent: the Abstract and Sect. 3.4 quote a median of ~2.2e-8 Msun/yr, Sect. 4.3 states a 'mean level of 3×10^-8 M⊙/yr', and Table 4 gives <log Mdot> = -7.76 (≈1.7e-8 Msun/yr). Please harmonize and explicitly state how upper limits (weak accretors) are included in the median and mean.
  2. [Various] Typos: 'calalogues' (Conclusions), 'alghough' (Sect. 4.1), 'overastimate' (Sect. 3.4), 'Finaal' (Sect. 3.4), 'irrispective' (Sect. 3.2.1), 'NGC 3606' (Sect. 4.2), 'reelations' (Sect. 4.1 header).
  3. [Fig. 7] The red-channel wavelength range is given as '540 nm–1 mm' in the Figure 7 caption; this should be '540 nm–1 µm' (or '1000 nm').
  4. [Sect. 4.1] For the Lupus comparison slopes, no uncertainties are quoted. Given that the Sh2-284 slopes for Hβ and Hγ overlap with the Lupus values at the 1-σ level, it would be helpful to report the Lupus slope uncertainties so the reader can judge the significance of the flattening, especially for the Ca II lines where the difference appears largest.

Circularity Check

0 steps flagged

No circularity: new line-flux data are interpreted with standard external calibrations, with the metallicity-transfer limitation explicitly acknowledged.

full rationale

The paper's central quantitative step is to convert measured line luminosities into accretion luminosities/rates using the empirical L_line-L_acc calibrations of Alcala et al. (2017), a work co-authored by several of the present authors. This is load-bearing for the absolute Ṃdot scale, but it is not circular: the calibrations were fitted to Lupus data, not to the present Sh2-284 line fluxes, and they are externally anchored, falsifiable empirical relations. The paper itself flags the only real limitation, stating (Sect. 3.3) that internal agreement across diagnostics 'does not constitute an independent validation of our absolute accretion scale' because 'all line diagnostics are anchored to the empirical calibrations of Alcala et al. (2017)', and (Sect. 3.5) that 'both methods rely on empirical calibrations derived from nearby, solar-metallicity populations... may mask subtle chemical dependencies in the gas cooling rates'. Those are caveats about external validity at low metallicity, not circular derivations. The flux-flux flattening claim is a direct empirical comparison of measured line fluxes with published Lupus relations; the paper explicitly states the slopes overlap within 1σ and that the null hypothesis cannot be rejected. The selection of Hα-excess, disk-bearing targets does favor accretors, but the paper is transparent about that selection and the derived accretion rates are not merely echoes of the selection thresholds. No equation in the paper reduces to its own input by construction, and no load-bearing premise depends on an unverified self-citation.

Axiom & Free-Parameter Ledger

4 free parameters · 6 axioms · 0 invented entities

The paper introduces no new physical entities. It relies on external empirical calibrations and standard PMS models; the most consequential upstream input is the solar-metallicity Lacc-Lline calibration, whose metallicity invariance is assumed and explicitly acknowledged as a limitation.

free parameters (4)
  • L_acc/L_line calibration coefficients (Alcala+2017, Table B.1) = slopes and intercepts from Lupus YSOs
    External empirical calibration fitted to solar-metallicity Lupus stars; every Mdot in this paper inherits its zero-point and slope.
  • R_in/R_star ratio = 5
    Adopted from Gullbring+1998 (Section 3.4) to convert L_acc to Mdot; sets the 1.25 prefactor in Eq. 1 and is not measured here.
  • Per-target visual extinction A_V = individual values from Guarcello+2021
    Used for extinction-corrected line fluxes and stellar luminosities; adopted from the parent catalogue rather than redetermined.
  • Cluster distance = 4.7 +/- 0.5 kpc
    Weighted mean of Gaia DR3 parallaxes; enters every line luminosity and stellar luminosity, and therefore Mdot.
axioms (6)
  • domain assumption Solar-metallicity Lacc-Lline empirical calibrations apply unchanged at Z ~ 1/3 Zsun.
    Invoked in Section 3.3 and acknowledged as a key limitation in Section 4.1; if false, absolute Mdot values and metallicity comparisons shift.
  • domain assumption Magnetospheric accretion geometry with Rin = 5 Rstar (Gullbring+1998) describes all targets.
    Used in Eq. 1 to convert accretion luminosity into mass accretion rate.
  • domain assumption A common cluster distance of 4.7 +/- 0.5 kpc is valid for all targets.
    Adopted in Section 3.1.4; depth of the complex is assumed negligible against parallax uncertainties.
  • domain assumption Extinction law and A_V values from Guarcello+2021 are reliable for this region.
    Used for extinction-corrected fluxes, luminosities, and Teff; errors propagate into Mdot.
  • domain assumption MIST/PARSEC pre-main-sequence tracks at Z ~ 0.005 provide correct masses, radii, and ages.
    Stellar masses and radii come from HR-diagram interpolation onto theoretical tracks (Section 3.1.4).
  • domain assumption BT-Settl synthetic spectra with [Fe/H]=-0.5 and log g=4.7 define the Teff scale.
    Teff from Na I and H-beta wings relies on this grid; the paper estimates +/-60-120 K sensitivity to log g and [Fe/H].

pith-pipeline@v1.3.0-alltime-deepseek · 41380 in / 13977 out tokens · 145295 ms · 2026-08-01T04:24:00.163997+00:00 · methodology

0 comments
read the original abstract

We present a spectroscopic survey of young stellar objects (YSOs) in Sh2-284, a distant (~4.5 kpc), low-metallicity (Z~1/3 Zsun) star-forming region (SFR) toward the Galactic anticenter. Candidate YSOs were selected using mid-infrared Spitzer/IRAC data with optical and near-infrared photometry. Follow-up spectroscopy was conducted with MODS at the Large Binocular Telescope. We characterize the stellar and accretion properties of the disk-bearing population in a metal-poor environment, probing stellar masses from ~2.95 Msun to ~0.35 Msun. This work constitutes the first wide-field (~45'x45') spectroscopic investigation of YSOs in Sh2-284, providing a comprehensive view of star formation in this Galactic environment. We provide tentative first estimates of iron abundance for three low-mass targets and lithium abundance for a limited number of objects, offering an initial characterization of the chemical properties of these stars. We adopt a multi-diagnostic approach based on nine tracers, exploiting the spectral coverage of the instrument, using H_alpha, H_beta, H_gamma, CaII infrared triplet, Pa_eta, Pa_zeta, and Pa_epsilon emission lines. We derive key accretion properties and compare them with those measured in nearby, solar-metallicity SFRs to explore potential metallicity-driven differences in accretion behavior and disk evolution. We tentatively find indications of a flattening in the flux-flux relations of the metal-poor YSOs compared to solar-metallicity samples, a behavior that is recovered across diagnostics. Our observations indicate that the selected disk-bearing YSOs in this metal-poor environment exhibit resilient accretion activity, spanning from ~2.3x10^(-10) Msun/yr and ~1.0x10^(-6) Msun/yr, and a median rate of ~2.2x10^(-8) Msun/yr. Overall, this demonstrates that gas accretion can be efficiently sustained in sub-solar metallicity environments.

Figures

Figures reproduced from arXiv: 2607.22533 by Brunella Nisini, Diego Paris, Ester Marini, Felice Cusano, Guido De Marchi, Juan Manuel Alcal\'a, Katia Biazzo, Maria Gabriela Navarro Ovando, Mario Guarcello, Roberta Carini, Simone Antoniucci, Teresa Giannini.

Figure 1
Figure 1. Figure 1: VPHAS+ image of the Sh2-284 SFR. VPHAS+ uses VST/OmegaCAM to survey the southern Galactic plane in ugriHα bands. Blue squares represent the nine MODS fields observed in multi-object mode (see upper part of [PITH_FULL_IMAGE:figures/full_fig_p005_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: Color-color diagrams of the Sh2-284 targets. Small grey dots are sources from the catalogue by Guarcello et al. (2023), while green diamonds represent the 68 YSO candidates selected and then observed by us. Left: 2MASS J − H versus J − KS color-color diagram. The dwarf (lower branch; Bessell & Brett 1988) and the giant (upper branch; Kenyon & Hartmann 1995) sequences are marked by solid lines. The CTTs loc… view at source ↗
Figure 3
Figure 3. Figure 3: Proper motions vector point diagram for the observed sample. Points are color-coded accord￾ing to their Gaia RUWE value showed in the colored right bar. The dotted cross-hair represents the posi￾tion of the center (< µαcosδ >= −0.312 ± 0.823 mas/yr, < µδ >= 0.249 ± 0.651 mas/yr) where most of the targets are clustered. The dashed and dot-dashed magenta concen￾tric ellipses denote the empirical boundaries a… view at source ↗
Figure 4
Figure 4. Figure 4: Measured T Na eff versus EWNa of our targets (green diamonds). The triangles, squares, and asterisks refer to val￾ues obtained using BT-Settl synthetic spectra at [Fe/H]=0.0, −0.5, −1.0 dex, respectively. Dashed line marks the least- -squares fit to the values obtained at [Fe/H]=−0.5 and used for the T Na eff . Continuous line represents the relation by Tripicchio et al. (1997) obtained using atmospheric m… view at source ↗
Figure 5
Figure 5. Figure 5: Lithium equivalent width (left panel) and Li abundance (right panel) as a function of the mean effective temperature. Filled symbols denote measured equivalent widths (EWs), while open symbols indicate EWs corrected for spectral veiling. In the left panel, the dashed line shows the curve of growth (COG) for FGKM stars with lithium abundance of 3.3 dex from Franciosini et al. (2022). In the right panel, lit… view at source ↗
Figure 6
Figure 6. Figure 6: Location of the YSOs candidates in the HR dia￾gram. Superimposed are the MIST evolutionary tracks (col￾ored solid lines) and theoretical isochrones (dot-dashed ma￾genta lines) of Choi et al. (2016) for metallicity Z ∼ 0.005. The masses in M⊙ and ages in Myr are indicated next to each track and isochrone, respectively. The position of the ZAMS is marked with a dashed violet line. (2015) found ages below 3 M… view at source ↗
Figure 7
Figure 7. Figure 7: Example of a MODS spectrum of a YSO candidate obtained with the blue (∼320-590 nm) and red (∼540 nm-1 mm) gratings. Emission of accretion diagnostics, such as Hα, Hβ, Hγ, Caii H&K lines and infrared triplet, and the Paschen series is evident, as marked in the plot. ID38), which exhibit an Hα emission reversal superim￾posed on the photospheric absorption and an inverse P-Cygni profile, are located in close … view at source ↗
Figure 8
Figure 8. Figure 8: Equivalent width of the Hα line versus IPHAS r −Hα (up), 2MASS J −K (middle), and Spitzer [3.6]−[4.5] (below) colors. Blue dots mark the sources with detected emission of the Caii infrared triplet lines. Bigger dots repre￾sent targets with EW of the Caii line at λ ∼ 8662 ˚A greater than 3 ˚A. Diamonds, small dots, and squares are targets with Hβ, Hγ, and Paschen lines in emission, respectively. Crosses in … view at source ↗
Figure 9
Figure 9. Figure 9: Hα equivalent width (left panel) and flux (right panel) versus Teff . Symbols as in [PITH_FULL_IMAGE:figures/full_fig_p017_9.png] view at source ↗
Figure 10
Figure 10. Figure 10: Comparison between the mass accretion rates derived in Sect. 3.4 and those obtained from the M˙ acc–Lline relationships of Micolta et al. (2023), using Hα (squares) and the three Ca II IRT lines (diamonds). The mean uncertainty is indicated in the lower-right corner of the panel. Moreover, in [PITH_FULL_IMAGE:figures/full_fig_p018_10.png] view at source ↗
Figure 11
Figure 11. Figure 11: Flux-flux relations between Hα and Balmer-series, and Ca-IRT, Paschen-series lines. The colored red dashed, green dot-dashed, and blue dotted lines refer to the least-square regressions for the different lines marked in the upper-left corner of each panel. The grey dashed, dot-dashed, and dotted lines refer to the corresponding flux-flux relations found by Alcal´a et al. (2017) for the hydrogen lines and … view at source ↗
Figure 13
Figure 13. Figure 13: Mean accretion luminosity derived from the dif￾ferent emission lines, as described in the text, as a function of the mean effective temperature measurements. Weak ac￾cretors are marked with arrows as upper limits. The long arrow on the right refers to the target with bad removal of the background. Symbols refer to different regions analyzed in the literature through spectroscopy, as indicated in the panel… view at source ↗
Figure 14
Figure 14. Figure 14: Mean accretion luminosity versus mean stel￾lar luminosities. Symbols as in [PITH_FULL_IMAGE:figures/full_fig_p022_14.png] view at source ↗
Figure 15
Figure 15. Figure 15: Mean mass accretion rate as a function of mean stellar mass for our YSO sample, compared with literature measurements from several well-studied star-forming regions spanning a wide range of metallicities and environments (labels indicated in the panel). Downward arrows mark upper limits. The chromospheric emission thresholds from Manara et al. (2017) are shown as dash-dotted and dashed lines, correspondin… view at source ↗

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

131 extracted references · 7 canonical work pages · 1 internal anchor

  1. [1]

    , year = 1973, month = sep, volume =

    The nitrogen abundance of the very metal-poor star HD 122563. , year = 1973, month = sep, volume =. doi:10.1086/152374 , adsurl =

    doi:10.1086/152374 1973

  2. [2]

    , keywords =

    SIPGI: an interactive pipeline for spectroscopic data reduction. , keywords =. doi:10.1093/mnras/stac1065 , archivePrefix =. 2209.05441 , primaryClass =

    Pith/arXiv arXiv

  3. [3]

    , keywords =

    The ATLAS All-Sky Stellar Reference Catalog. , keywords =. doi:10.3847/1538-4357/aae386 , archivePrefix =. 1809.09157 , primaryClass =

    Pith/arXiv arXiv

  4. [4]

    , keywords =

    SExtractor: Software for source extraction. , keywords =. doi:10.1051/aas:1996164 , adsurl =

    doi:10.1051/aas:1996164

  5. [5]

    , keywords =

    The Hawk-I UDS and GOODS Survey (HUGS): Survey design and deep K-band number counts. , keywords =. doi:10.1051/0004-6361/201423543 , archivePrefix =. 1409.7082 , primaryClass =

    Pith/arXiv arXiv

  6. [6]

    Astronomical Data Analysis Software and Systems XV , year = 2006, editor =

    Automatic Astrometric and Photometric Calibration with SCAMP. Astronomical Data Analysis Software and Systems XV , year = 2006, editor =

    2006

  7. [7]

    SWarp: Resampling and Co-adding FITS Images Together

  8. [8]

    , year = 1959, month = dec, volume =

    A Catalogue of H II Regions. , year = 1959, month = dec, volume =. doi:10.1086/190049 , adsurl =

    doi:10.1086/190049 1959

  9. [9]

    , keywords =

    Pre-main-sequence stars in the star-forming complex Sh 2-284. , keywords =. doi:10.1111/j.1365-2966.2010.17438.x , archivePrefix =. 1009.0435 , primaryClass =

    arXiv 2010

  10. [10]

    , keywords =

    Open cluster Dolidze 25: Stellar parameters and the metallicity in the Galactic anticentre. , keywords =. doi:10.1051/0004-6361/201526784 , archivePrefix =. 1509.04312 , primaryClass =

    Pith/arXiv arXiv

  11. [11]

    , keywords =

    Precision Photometry of Young Stellar Groups Towards the Outer Galactic Disk and the Galactic Rotation Curve. , keywords =. doi:10.1086/116558 , adsurl =

    work page doi:10.1086/116558

  12. [12]

    , keywords =

    Dolidze 25 : a metal-deficient galactic open cluster. , keywords =

  13. [13]

    Searching for evidence of triggered star formation in an isolated region in the outer Milky Way

    Spitzer/IRAC view of Sh 2-284. Searching for evidence of triggered star formation in an isolated region in the outer Milky Way. , keywords =. doi:10.1051/0004-6361/200810664 , archivePrefix =. 0907.1253 , primaryClass =

    Pith/arXiv arXiv

  14. [14]

    , keywords =

    Protoplanetary Disks around Sun-like Stars Appear to Live Longer When the Metallicity is Low. , keywords =. doi:10.3847/1538-4357/ad7a63 , archivePrefix =. 2412.10361 , primaryClass =

    Pith/arXiv arXiv

  15. [15]

    Externally irradiated young stars in NGC 3603. A JWST NIRSpec catalogue of pre-main-sequence stars in a massive star formation region

    Externally irradiated young stars in NGC 3603. A JWST NIRSpec catalogue of pre-main-sequence stars in a massive star formation region. arXiv e-prints , keywords =. doi:10.48550/arXiv.2412.05650 , archivePrefix =. 2412.05650 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.48550/arxiv.2412.05650

  16. [16]

    Ground-based and Airborne Instrumentation for Astronomy III , year = 2010, editor =

    The multi-object double spectrographs for the Large Binocular Telescope. Ground-based and Airborne Instrumentation for Astronomy III , year = 2010, editor =. doi:10.1117/12.857215 , adsurl =

    doi:10.1117/12.857215 2010

  17. [17]

    Summary of the content and survey properties

    Gaia Data Release 3. Summary of the content and survey properties. , keywords =. doi:10.1051/0004-6361/202243940 , archivePrefix =. 2208.00211 , primaryClass =

    Pith/arXiv arXiv

  18. [18]

    Photometric determination of the mass accretion rates of pre-main-sequence stars. VII. The low-density cluster NGC 376 in the Small Magellanic Cloud. , keywords =. doi:10.1051/0004-6361/202142838 , archivePrefix =. 2301.09625 , primaryClass =

    Pith/arXiv arXiv

  19. [19]

    Photometric determination of the mass accretion rates of pre-main-sequence stars. VIII. Recent star formation in NGC 299. , keywords =. doi:10.1051/0004-6361/202245248 , archivePrefix =. 2304.12137 , primaryClass =

    Pith/arXiv arXiv

  20. [20]

    , keywords =

    Pre-main sequence stars in LH 91. , keywords =. doi:10.1051/0004-6361/202243118 , archivePrefix =. 2203.13647 , primaryClass =

    Pith/arXiv arXiv

  21. [21]

    Photometric Determination of the Mass Accretion Rates of Pre-main-sequence Stars. VI. The Case of LH 95 in the Large Magellanic Cloud. , keywords =. doi:10.3847/1538-4357/ab0f95 , archivePrefix =. 1903.07610 , primaryClass =

    Pith/arXiv arXiv 1903

  22. [22]

    Photometric Determination of the Mass Accretion Rates of Pre-main-sequence Stars. I. Method and Application to the SN 1987A Field. , keywords =. doi:10.1088/0004-637X/715/1/1 , archivePrefix =. 1002.4864 , primaryClass =

    Pith/arXiv arXiv

  23. [23]

    Photometric Determination of the Mass Accretion Rates of Pre-main-sequence Stars. IV. Recent Star Formation in NGC 602. , keywords =. doi:10.1088/0004-637X/775/1/68 , archivePrefix =. 1307.8445 , primaryClass =

    Pith/arXiv arXiv

  24. [24]

    , keywords =

    Photoevaporation and Close Encounters: How the Environment around Cygnus OB2 Affects the Evolution of Protoplanetary Disks. , keywords =. doi:10.3847/1538-4365/acdd67 , adsurl =

    work page doi:10.3847/1538-4365/acdd67

  25. [25]

    Radiation Hydrodynamics Simulations of Photoevaporation of Protoplanetary Disks. II. Metallicity Dependence of UV and X-Ray Photoevaporation. , keywords =. doi:10.3847/1538-4357/aad9fd , archivePrefix =. 1805.07992 , primaryClass =

    Pith/arXiv arXiv

  26. [26]

    , year = 2016, month = sep, volume =

    Accretion onto Pre-Main-Sequence Stars. , year = 2016, month = sep, volume =. doi:10.1146/annurev-astro-081915-023347 , adsurl =

    doi:10.1146/annurev-astro-081915-023347 2016

  27. [27]

    , keywords =

    Timescale of mass accretion in pre-main-sequence stars. , keywords =. doi:10.1051/0004-6361/200912810 , archivePrefix =. 0911.3320 , primaryClass =

    Pith/arXiv arXiv

  28. [28]

    , keywords =

    The Transitional Protoplanetary Disk Frequency as a Function of Age: Disk Evolution In the Coronet Cluster, Taurus, and Other 1-8 Myr Old Regions. , keywords =. doi:10.1088/0004-637X/732/1/24 , archivePrefix =. 1102.4364 , primaryClass =

    Pith/arXiv arXiv

  29. [29]

    , keywords =

    Disk Evolution in the Orion OB1 Association. , keywords =. doi:10.1086/426910 , archivePrefix =. astro-ph/0410522 , primaryClass =

    Pith/arXiv arXiv

  30. [30]

    , keywords =

    Cepheus OB2: Disk Evolution and Accretion at 3-10 Myr. , keywords =. doi:10.1086/430748 , adsurl =

    doi:10.1086/430748

  31. [31]

    Protostars and Planets VII , year = 2023, editor =

    Demographics of Young Stars and their Protoplanetary Disks: Lessons Learned on Disk Evolution and its Connection to Planet Formation. Protostars and Planets VII , year = 2023, editor =. doi:10.48550/arXiv.2203.09930 , archivePrefix =. 2203.09930 , primaryClass =

    Pith/arXiv arXiv doi:10.48550/arxiv.2203.09930 2023

  32. [32]

    , keywords =

    Metallicity, planet formation and disc lifetimes. , keywords =. doi:10.1111/j.1365-2966.2009.16094.x , archivePrefix =. 0910.5110 , primaryClass =

    arXiv 2009

  33. [33]

    Journal of Geophysical Research (Planets) , keywords =

    Challenges in planet formation. Journal of Geophysical Research (Planets) , keywords =. doi:10.1002/2016JE005088 , archivePrefix =. 1610.07202 , primaryClass =

    Pith/arXiv arXiv

  34. [34]

    , keywords =

    Disk Accretion onto Magnetic T Tauri Stars. , keywords =. doi:10.1086/185972 , adsurl =

    doi:10.1086/185972

  35. [35]

    , keywords =

    The Lifetime of Protoplanetary Disks in a Low-metallicity Environment. , keywords =. doi:10.1088/0004-637X/705/1/54 , archivePrefix =. 0908.4026 , primaryClass =

    Pith/arXiv arXiv

  36. [36]

    Low-metallicity Young Clusters in the Outer Galaxy. II. Sh 2-208. , keywords =. doi:10.3847/0004-6256/151/5/115 , archivePrefix =. 1604.00144 , primaryClass =

    Pith/arXiv arXiv

  37. [37]

    , keywords =

    Pre-Main-Sequence Evolution in the Taurus-Auriga Molecular Cloud. , keywords =. doi:10.1086/192235 , adsurl =

    doi:10.1086/192235

  38. [38]

    , keywords =

    JHKLM Photometry: Standard Systems, Passbands, and Intrinsic Colors. , keywords =. doi:10.1086/132281 , adsurl =

    doi:10.1086/132281

  39. [39]

    , year = 1997, month = jul, volume =

    Intrinsic Near-Infrared Excesses of T Tauri Stars: Understanding the Classical T Tauri Star Locus. , year = 1997, month = jul, volume =. doi:10.1086/118474 , adsurl =

    doi:10.1086/118474 1997

  40. [40]

    , keywords =

    Infrared Array Camera (IRAC) Colors of Young Stellar Objects. , keywords =. doi:10.1086/422715 , adsurl =

    doi:10.1086/422715

  41. [41]

    , keywords =

    The INT Photometric H Survey of the Northern Galactic Plane (IPHAS). , keywords =. doi:10.1111/j.1365-2966.2005.09330.x , archivePrefix =. astro-ph/0506726 , primaryClass =

    arXiv 2005

  42. [42]

    , keywords =

    T Tauri candidates and accretion rates using IPHAS: method and application to IC 1396. , keywords =. doi:10.1111/j.1365-2966.2011.18674.x , archivePrefix =. 1103.1646 , primaryClass =

    arXiv 2011

  43. [43]

    , keywords =

    Pre-main-sequence Accretion in the Low Metallicity Galactic Star-forming Region Sh 2-284. , keywords =. doi:10.1088/0004-637X/800/2/113 , archivePrefix =. 1412.2014 , primaryClass =

    Pith/arXiv arXiv 2014

  44. [44]

    LZ-STAR Survey: Low-metallicity Star Formation Survey of Sh2-284. I. Ordered Massive Star Formation in the Outer Galaxy. , keywords =. doi:10.3847/1538-4357/addf4b , archivePrefix =. 2503.14460 , primaryClass =

    Pith/arXiv arXiv

  45. [45]

    Low-Metallicity Star Formation Survey in Sh2-284 (LZ-STAR). II. The inital mass function. arXiv e-prints , keywords =. doi:10.48550/arXiv.2505.12802 , archivePrefix =. 2505.12802 , primaryClass =

    Pith/arXiv arXiv doi:10.48550/arxiv.2505.12802

  46. [46]

    , keywords =

    Dispersal timescale of protoplanetary disks in the low-metallicity young cluster Dolidze 25. , keywords =. doi:10.1051/0004-6361/202140361 , archivePrefix =. 2104.05840 , primaryClass =

    Pith/arXiv arXiv

  47. [47]

    , keywords =

    Uncovering the Hidden Physical Structures and Protostellar Activities in the Low-metallicity S284-RE Region: Results from ALMA and JWST. , keywords =. doi:10.3847/1538-4357/ada388 , archivePrefix =. 2412.20364 , primaryClass =

    Pith/arXiv arXiv

  48. [48]

    Philosophical Transactions of the Royal Society of London Series A , keywords =

    Models of very-low-mass stars, brown dwarfs and exoplanets. Philosophical Transactions of the Royal Society of London Series A , keywords =. doi:10.1098/rsta.2011.0269 , archivePrefix =. 1112.3591 , primaryClass =

    arXiv 2011

  49. [49]

    , keywords =

    Chemical compositions of four B-type supergiants in the SMC wing. , keywords =. doi:10.1051/0004-6361:20041345 , archivePrefix =. astro-ph/0410318 , primaryClass =

    Pith/arXiv arXiv

  50. [50]

    Globular Cluster Abundances from High-resolution, Integrated-light Spectroscopy. IV. The Large Magellanic Cloud: , Fe-peak, Light, and Heavy Elements. , keywords =. doi:10.1088/0004-637X/746/1/29 , archivePrefix =. 1111.6068 , primaryClass =

    Pith/arXiv arXiv

  51. [51]

    , keywords =

    Detailed analysis of Balmer lines in cool dwarf stars. , keywords =. doi:10.1051/0004-6361:20020163 , archivePrefix =. astro-ph/0201537 , primaryClass =

    Pith/arXiv arXiv

  52. [52]

    Physica Scripta Volume T , year = 2008, month = dec, volume =

    Hydrogen lines. Physica Scripta Volume T , year = 2008, month = dec, volume =. doi:10.1088/0031-8949/2008/T133/014023 , adsurl =

    work page doi:10.1088/0031-8949/2008/t133/014023 2008

  53. [53]

    , keywords =

    The NaI resonance lines as a spectroscopic test of late-type stellar atmospheres. , keywords =

  54. [54]

    , keywords =

    The GALAH survey: effective temperature calibration from the InfraRed Flux Method in the Gaia system. , keywords =. doi:10.1093/mnras/stab2304 , archivePrefix =. 2011.02517 , primaryClass =

    Pith/arXiv arXiv 2011

  55. [55]

    GIARPS High-resolution Observations of T Tauri stars (GHOsT). III. A pilot study of stellar and accretion properties. , keywords =. doi:10.1051/0004-6361/202140918 , archivePrefix =. 2106.10724 , primaryClass =

    Pith/arXiv arXiv

  56. [56]

    , keywords =

    Intrinsic Colors, Temperatures, and Bolometric Corrections of Pre-main-sequence Stars. , keywords =. doi:10.1088/0067-0049/208/1/9 , archivePrefix =. 1307.2657 , primaryClass =

    Pith/arXiv arXiv

  57. [57]

    Estimating Distances from Parallaxes. V. Geometric and Photogeometric Distances to 1.47 Billion Stars in Gaia Early Data Release 3. , keywords =. doi:10.3847/1538-3881/abd806 , archivePrefix =. 2012.05220 , primaryClass =

    Pith/arXiv arXiv 2012

  58. [58]

    Parallax bias versus magnitude, colour, and position

    Gaia Early Data Release 3. Parallax bias versus magnitude, colour, and position. , keywords =. doi:10.1051/0004-6361/202039653 , archivePrefix =. 2012.01742 , primaryClass =

    Pith/arXiv arXiv 2012

  59. [59]

    Accretion properties of class II and transitional objects

    X-shooter spectroscopy of young stellar objects in Lupus. Accretion properties of class II and transitional objects. , keywords =. doi:10.1051/0004-6361/201629929 , archivePrefix =. 1612.07054 , primaryClass =

    Pith/arXiv arXiv

  60. [60]

    The X-shooter view

    Connection between jets, winds and accretion in T Tauri stars. The X-shooter view. , keywords =. doi:10.1051/0004-6361/201730834 , archivePrefix =. 1710.05587 , primaryClass =

    Pith/arXiv arXiv

  61. [61]

    Atmospheric parameters, membership, and activity diagnostics

    X-shooter spectroscopy of young stellar objects in Lupus. Atmospheric parameters, membership, and activity diagnostics. , keywords =. doi:10.1051/0004-6361/201630108 , archivePrefix =. 1703.01251 , primaryClass =

    Pith/arXiv arXiv

  62. [62]

    , keywords =

    H survey of late-type active binaries. , keywords =

  63. [63]

    , keywords =

    The young active star SAO 51891 (V383 Lacertae). , keywords =. doi:10.1051/0004-6361/200811480 , archivePrefix =. 0903.3141 , primaryClass =

    Pith/arXiv arXiv

  64. [64]

    , keywords =

    Gaia23bab: A New EXor. , keywords =. doi:10.3847/1538-4357/ad39e2 , archivePrefix =. 2404.01974 , primaryClass =

    Pith/arXiv arXiv

  65. [65]

    , keywords =

    Disk Frequencies and Lifetimes in Young Clusters. , keywords =. doi:10.1086/320685 , archivePrefix =. astro-ph/0104347 , primaryClass =

    Pith/arXiv arXiv

  66. [66]

    X-shooter spectroscopy of young stellar objects. II. Impact of chromospheric emission on accretion rate estimates. , keywords =. doi:10.1051/0004-6361/201220921 , archivePrefix =. 1301.3058 , primaryClass =

    Pith/arXiv arXiv

  67. [67]

    , keywords =

    Disk Accretion Rates for T Tauri Stars. , keywords =. doi:10.1086/305032 , adsurl =

    doi:10.1086/305032

  68. [68]

    , keywords =

    The Gaia-ESO Survey: Chromospheric emission, accretion properties, and rotation in Velorum and Chamaeleon I. , keywords =. doi:10.1051/0004-6361/201424409 , archivePrefix =. 1412.4153 , primaryClass =

    Pith/arXiv arXiv

  69. [69]

    , keywords =

    Very Low Mass Stars and Brown Dwarfs in Taurus-Auriga. , keywords =. doi:10.1086/344673 , archivePrefix =. astro-ph/0209164 , primaryClass =

    Pith/arXiv arXiv

  70. [70]

    X-shooter spectroscopy of young stellar objects. IV. Accretion in low-mass stars and substellar objects in Lupus. , keywords =. doi:10.1051/0004-6361/201322254 , archivePrefix =. 1310.2069 , primaryClass =

    Pith/arXiv arXiv 2069

  71. [71]

    Photometric Determination of the Mass Accretion Rates of Pre-main-sequence Stars. V. Recent Star Formation in the 30 Dor Nebula. , keywords =. doi:10.3847/1538-4357/aa85e9 , archivePrefix =. 1708.03631 , primaryClass =

    Pith/arXiv arXiv

  72. [72]

    X-shooter spectroscopy of young stellar objects. I. Mass accretion rates of low-mass T Tauri stars in Orionis. , keywords =. doi:10.1051/0004-6361/201219832 , archivePrefix =. 1209.5799 , primaryClass =

    Pith/arXiv arXiv

  73. [73]

    , keywords =

    On the accretion properties of young stellar objects in the L1615/L1616 cometary cloud. , keywords =. doi:10.1051/0004-6361/201424249 , archivePrefix =. 1409.2411 , primaryClass =

    Pith/arXiv arXiv

  74. [74]

    , keywords =

    Variability of the transitional T Tauri star T Chamaeleontis. , keywords =. doi:10.1051/0004-6361/200811073 , archivePrefix =. 0904.0101 , primaryClass =

    Pith/arXiv arXiv

  75. [75]

    , keywords =

    The Chamaeleon II low-mass star-forming region: radial velocities, elemental abundances, and accretion properties. , keywords =. doi:10.1051/0004-6361/201219680 , archivePrefix =. 1209.5316 , primaryClass =

    Pith/arXiv arXiv

  76. [76]

    , keywords =

    Catalogue of UBVRI Photometry of T Tauri Stars and Analysis of the Causes of Their Variability. , keywords =. doi:10.1086/117204 , adsurl =

    doi:10.1086/117204

  77. [78]

    , keywords =

    Temperaments of young stars: rapid mass accretion rate changes in T Tauri and Herbig Ae stars. , keywords =. doi:10.1093/mnras/stu529 , archivePrefix =. 1403.4088 , primaryClass =

    Pith/arXiv arXiv

  78. [79]

    Protostars and Planets VII , year = 2023, editor =

    Accretion Variability as a Guide to Stellar Mass Assembly. Protostars and Planets VII , year = 2023, editor =. doi:10.48550/arXiv.2203.11257 , archivePrefix =. 2203.11257 , primaryClass =

    Pith/arXiv arXiv doi:10.48550/arxiv.2203.11257 2023

  79. [80]

    , keywords =

    How Variable is Accretion in Young Stars?. , keywords =. doi:10.1088/0004-637X/694/2/L153 , archivePrefix =. 0902.4235 , primaryClass =

    Pith/arXiv arXiv

  80. [81]

    , keywords =

    Multicolor Variability of Young Stars in the Lagoon Nebula: Driving Causes and Intrinsic Timescales. , keywords =. doi:10.3847/1538-3881/ac0536 , archivePrefix =. 2105.11588 , primaryClass =

    Pith/arXiv arXiv

Showing first 80 references.