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A Long-term photometric variability and spectroscopic study of luminous blue variable AF And in M31

T0 review · 2 major / 6 minor · reviewed 2026-08-14 · deepseek-v4-flash

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Pith's one-line read Thirteen years of R/I photometry and spectra of the luminous blue variable AF And in M31 catch a 1.5-magnitude eruption in January 1999, a three-year fade, and a smaller 2010 outburst, with the quiescent star a 33,000 K wind source.

desk verdict The new photometry of AF And is worth having, but the quoted mass-loss rate is an artifact of using the H-alpha line width as an expansion speed. read the letter →

arxiv 1908.01893 v1 pith:KNCO3MYK submitted 2019-08-05 astro-ph.SR

Yogesh C. Joshi (ARIES) , Kaushal Sharma (IUCAA) , Anjasha Gangopadhyay (ARIES) , Rishikesh Gokhale (SBU) , Kuntal Misra (ARIES) This is my paper · ORCID
classification astro-ph.SR
keywords luminousbluevariablesAFAndM31photometricvariabilitystellarwindsmasslossPCygniprofilespectralenergydistribution
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

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

The reading

The paper uses 169 nights of Cousins R and I photometry spread over about 5,000 days to reconstruct two eruptions of AF And, a luminous blue variable in the Andromeda galaxy. It catches the star near the peak of a major outburst on 16 January 1999, when it reached $R=15.896$ mag, and then follows a slow fade of about 1.5 mag over roughly three years into a quiescent phase by late 2001. After about nine quiet years, a secondary outburst with an amplitude of 0.44 mag appears in late 2010 and lasts about a year. Spectroscopy from 2016 supplies the physical picture of the quiescent star: an SED fit gives a photospheric temperature of $33{,}000\pm3{,}000$ K, a weak He I P Cygni profile gives a wind terminal velocity of 280–300 km/s, and the line asymmetries imply a mass-loss rate near $2.2\times10^{-4}$ solar masses per year. A sympathetic reader would care because these long-term records tie the brightness changes to temperature and wind changes, testing how the most massive stars shed mass before exploding.

What carries the argument

The load-bearing object is the 5,000-day R/I light curve and its colour-magnitude track, read through the standard LBV pseudo-photosphere picture: when the wind becomes optically thick, the star presents a cool, extended, bright pseudo-photosphere at roughly constant bolometric luminosity, and when the wind thins, the photosphere retreats and the star heats toward its quiescent O-type state. Supporting tools are the dereddened SED fitted with blackbody and atmospheric models (giving $T_{\rm eff}=33{,}000\pm3{,}000$ K), the weak P Cygni profile of He I used to measure terminal velocity near 280–300 km/s, and the shock-energy mass-loss relation converting luminosity and wind speed into a mass-loss rate of about $2.2\times10^{-4}$ solar masses per year. The redder-when-brighter quadratic colour-magnitude fit is the direct observable signature that ties the brightness changes to temperature rather than to luminosity.

What would settle it

Recompute the SED fit and wind parameters using the Cepheid-based reddening $E(B-V)\approx0.29$ instead of 0.36; if the best-fit temperature leaves the 30,000–36,000 K range or the mass-loss rate changes substantially, the quoted physical parameters are not robust. A high-resolution spectrum of the He I 5876 Å P Cygni absorption edge would also settle whether the terminal velocity is really 280–300 km/s rather than the roughly 105–150 km/s reported at earlier minima.

Watch

Extended reading notes

Core claim

The central claim is that AF And is a recurrent eruptor whose major and minor outbursts are photospheric phenomena: in the 1999 event the star brightened by about 1.5 mag while cooling from a quiescent temperature above 30,000 K to roughly 7,050 K at peak, then faded over about 1,027 days at roughly $0.0015$ mag/day as the pseudo-photosphere contracted and reheated. The same star produced a smaller 0.44 mag event in late 2010, lasting about a year. In the hot quiescent state, the authors find $T_{\rm eff}=33{,}000\pm3{,}000$ K from fitting the dereddened SED, a wind terminal velocity of 280–300 km/s from the He I 5876 Å P Cygni blue edge, and a mass-loss rate of about $2.2\times10^{-4}$ solar masses per year from the shock-energy mass-loss relation. They also estimate a peak bolometric luminosity of $\log(L/L_\odot)=5.7$, an O7-like spectral match, and a host metallicity near $12+\log(\mathrm{O/H})=8.7$–$8.9$. These numbers are presented as approximate, with the largest systematic uncertainty stated to be the adopted extinction.

Load-bearing premise

The adopted reddening, $E(B-V)=0.36$ mag taken as the average of two Galactic extinction maps, is the load-bearing premise: every quoted temperature, luminosity, and mass-loss rate shifts if the true line-of-sight extinction differs, and the paper deliberately discards the larger-uncertainty Cepheid-based value without propagating its effect.

Editorial extensions

If this is right

  • AF And should be treated as a recurrent eruptor: major 1–2 mag events and minor 0.4–0.6 mag events can both occur within a decade or two, so monitoring programs in M31 should expect them at any time.
  • The redder-when-brighter trend and the near-constant bolometric luminosity imply that AF And's eruption brightness changes are temperature and radius effects of a pseudo-photosphere, not true luminosity changes; future multi-band light curves can therefore be converted into photospheric temperature tracks.
  • The measured quiescent temperature near 33,000 K and the O7-like SED mean AF And in quiescence should look like a hot O-type supergiant with slow dense winds, so future quiescent spectra should resemble the 2016 spectrum rather than an eruption-phase F/A supergiant spectrum.
  • The slow terminal velocity (280–300 km/s) combined with the high mass-loss rate supports the picture of LBVs as near-Eddington stars that shed a large fraction of their envelope in eruptions, which should be taken into account in models of the star's current mass and future evolution.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • If the recurrence pattern of AF And holds, the next major eruption after the 2010 minor event could occur within the next decade or two; archival M31 photometry from 2015 onward could already contain the onset and is worth a targeted search.
  • The mass-loss rate depends on an assumed shock-heating efficiency of 0.5 and on the adopted terminal velocity, so the quoted $2.2\times10^{-4}$ solar masses per year is an order-of-magnitude estimate; varying the efficiency between 0.1 and 1 would change the rate by a factor of ten, which matters for the star's total mass budget.
  • Because the adopted extinction differs from the Cepheid-based estimate by about 0.07 mag in $E(B-V)$, a targeted measurement of AF And's line-of-sight extinction, for example from the colours of neighbouring stars or a resolved dust map, would directly test whether the 33,000 K temperature and $\log(L/L_\odot)=5.7$ luminosity need revision.
  • The small colour change during the 2010 minor event compared with the major 1999 event suggests minor eruptions may be mild photospheric adjustments rather than large mass ejections; high-cadence photometry and spectroscopy during the next minor event could verify that.
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Editorial analysis

A structured set of objections, weighed in public.

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

Referee Report

2 major / 6 minor

Summary. This paper presents a long-term photometric and spectroscopic study of the luminous blue variable AF And in M31, based primarily on R- and I-band observations from the Nainital Microlensing Survey (1998-2002) and follow-up monitoring through 2011. The authors report a major outburst peaking near 16 January 1999 at R = 15.896 ± 0.003 mag, followed by a gradual decline of about 1.5 mag over roughly three years (decay rate ~0.0015 mag/day), a quiescent phase beginning in late 2001, and a secondary outburst in late 2010 with amplitude ~0.44 mag. Spectroscopic observations from 2016 are used to identify Balmer, He I, Fe II, and [Fe II] emission, to estimate a photospheric temperature of about 33,000 ± 3,000 K from SED fitting, a wind terminal velocity of 280-300 km/s from a weak He I P Cygni feature, and a mass-loss rate of about 2.2e-4 solar masses per year from an assumed shock-powered luminosity relation. The paper also estimates the host metallicity from [N II]/H-alpha and O3N2 diagnostics.

Significance. If the photometric results are taken at face value, the paper provides a valuable, densely sampled record of a full LBV eruption and decline in M31, complementing the sparse historical coverage of AF And and independently confirming the secondary 2010 outburst seen in PanSTARRS data. The light-curve analysis, the colour evolution over the eruption, and the identification of the redder-when-brighter trend are robust contributions to the observational picture of Hubble-Sandage variables. The spectroscopic data, while of modest resolution, usefully document the quiescent-phase spectral appearance. However, the quantitative physical parameters derived in Sections 6.1-6.4 are considerably less secure: the mass-loss rate rests on an internally inconsistent choice of the shell velocity, and the temperature, luminosity, and mass-loss values inherit a large, unpropagated reddening uncertainty. These issues do not undermine the photometric monitoring claim, but they do affect several headline numbers in the abstract and summary.

major comments (2)
  1. [Section 6.4, Eq. (6)] The quoted mass-loss rate of 2.2e-4 M_sun/yr is not robust because the shell velocity v_LBV is set equal to the H-alpha FWHM, 2476 km/s, which is a line-broadening velocity scale, not the bulk radial velocity of an expanding shell. The paper itself adopts a wind terminal velocity of 280-300 km/s in Section 6.3 and states in Section 4.1.1 that LBV shells expand at roughly 100-200 km/s. Since Mdot scales as v_LBV^{-3}, substituting the paper's own terminal velocity of 280 km/s raises Mdot by a factor of about (2476/280)^3 ~ 690, to roughly 0.15 M_sun/yr; using a typical LBV shell speed of 150 km/s raises it further by an order of magnitude. The derivation therefore conflates two different velocity scales, and the headline mass-loss value is internally inconsistent with the measurement presented in the same paper. The authors should either justify the use of the FWHM as a physical expansion speed, replace it with an appropriate bulk velocity, or remove the quantitative claim and present the mass-loss rate only as an order-of-magnitude estimate with a clear dependence on the assumed velocity.
  2. [Sections 4.2, 6.1, and 6.4] The adopted reddening E(B-V) = 0.36 mag is the average of two extinction-map values (0.39 ± 0.05 and 0.33 ± 0.04 mag), yet the uncertainty on this adopted value is never propagated into the quoted photospheric temperature, bolometric luminosity, or mass-loss rate. The survey's own Cepheid-based E(R-I) = 0.16 ± 0.11 mag, which would imply E(B-V) ~ 0.29, is discarded as too uncertain, but the systematic effect of this choice is not quantified. Given that the SED-fitting Teff, the bolometric luminosity in Section 4.5, and the mass-loss estimate in Section 6.4 all shift noticeably with reddening, the paper should report a range of derived parameters over the plausible E(B-V) interval or at least state the sensitivity of each derived value to the adopted reddening.
minor comments (6)
  1. [Section 6.1] The VOSA fit is described as an 'independent confirmation' of the photospheric temperature, but it uses the same dereddened photometric magnitudes and the same E(B-V) = 0.36 mag as the manual SED fit, so the agreement is partly by construction. I suggest rephrasing this as a consistency check and discussing the systematic reddening uncertainty as the dominant limitation.
  2. [Section 6.3] The terminal velocity is derived from a weak P Cygni feature at R~1300 in a spectrum the authors themselves describe as low-resolution and with a possible Na D blend. The quoted uncertainty of 30-35 km/s reflects only the fitting scatter and omits systematic errors from line blending and the blue-edge definition; a sentence acknowledging this limitation would be appropriate.
  3. [Section 4.3] The conversion (B-V) = (R-I)/0.55 is introduced without a reference or justification for the factor 0.55, and the Flower (1996) colour-temperature relation is applied to the resulting colour without discussion of its applicability to unevolved versus evolved supergiants. A citation and justification would improve reproducibility.
  4. [Section 5] The Fe-Ne wavelength-calibration spectra for the gr7 setting were taken on previous nights rather than on the science night; this should be noted as a possible source of systematic wavelength error in the blue portion of the spectrum.
  5. [References] The in-text citation 'Groh et al. (2009)' corresponds to a reference entry listed as 'Groh, J. H., Hillier, D. J., Damineli, A., et al., 1993, ApJ, 698, 1698'; the year and volume appear inconsistent and should be verified.
  6. [Appendix / Section 7] The Appendix states that Martin & Humphreys (2017a) and Martin et al. (2017b) report a new outburst of AF And between 2015 and 2017, but this information does not appear in the discussion or summary. Adding a sentence connecting the 2010 secondary outburst to the later activity would place the present light curve in a fuller temporal context.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity; the photometric and spectroscopic results are data-driven and externally benchmarked.

full rationale

The central photometric claims are direct measurements from the time-series data: the 1999 outburst, the ~1.5 mag decline over three years, and the 2010 secondary outburst are read off Figure 1, and the secondary outburst is independently corroborated by Pan-STARRS data (Lee et al. 2014). The physical parameters are obtained by standard fitting procedures rather than by inserting the claimed result as an input. The photospheric temperature is derived by fitting reddening-corrected broadband photometry with blackbody and Kurucz models (Section 6.1); the terminal velocity comes from the blue edge of the He I P Cygni profile (Section 6.3); and the mass-loss rate is computed from the Chugai & Danziger (1994) relation using measured velocities (Section 6.4). None of these steps uses the target value to predict the same target value. The VOSA 'independent confirmation' uses the same photometric magnitudes and the same reddening, so it is not truly independent, but the Teff estimate is a fit to data and is not used to predict the same data in a way that closes the derivation chain. The separate physical concern that the H-alpha FWHM is used as v_LBV in Eq. (6) is an internal-consistency or robustness issue, not a circularity, because the mass-loss rate is still derived from an external formula and independently measured line quantities. Self-citations to Joshi et al. (2003, 2005) are used for data provenance and survey details, and the Cepheid-based reddening of Joshi et al. (2003) is explicitly set aside rather than being load-bearing. The analysis is therefore self-contained and not circular.

Assumptions & free parameters 3 free parameters · 6 assumptions · 0 invented entities

The central photometric variability claim rests directly on the calibrated light curves and does not require extra assumptions. However, all derived physical quantities (Teff, luminosity, mass-loss rate) rely on a chain of adopted parameters and empirical relations: an extinction E(B-V)=0.36 from two literature maps, a standard extinction law with R_V=3.07, a distance of 750 kpc, the Flower (1996) color-temperature relation, the assumption that LBV bolometric luminosity is constant during eruptions, and the Chugai & Danziger (1994) mass-loss relation with an ad hoc efficiency epsilon=0.5. No new entities are invented.

free parameters (3)
  • E(B-V) reddening = 0.36 mag (adopted average; range 0.33-0.39)
    Adopted from Schlegel et al. (1998) and Schlafly & Finkbeiner (2011) extinction maps; used to deredden all photometry and spectra, directly affecting temperature, luminosity, and mass-loss estimates. The two literature values differ by 0.06 mag, and the paper's own Cepheid-based estimate was discarded.
  • Mass-loss efficiency epsilon = 0.5
    Assumed conversion efficiency of shock kinetic energy to visual light in Eq. (6). The paper notes epsilon < 1 and that lower optical depth may reduce it; the value is chosen, not measured, and directly scales the derived mass-loss rate.
  • Distance to M31 = 750 kpc
    Adopted from Freedman et al. (2001) to convert apparent to absolute magnitudes and luminosity. The derived log(L/Lsun)=5.7 scales as distance squared.
assumptions (6)
  • domain assumption Standard extinction law with R_V=3.07
    Used to convert E(B-V) to A_V and to deredden individual bands; adopted from Fitzpatrick (1999).
  • domain assumption Flower (1996) color-temperature calibration for supergiants (Eq. 1)
    Converts (B-V) to Teff; this empirical relation carries its own scatter and is applied to a star with strong emission lines and reddening.
  • domain assumption Bolometric luminosity is roughly constant during LBV eruptions
    Used in Section 4.5 to equate peak and quiescent luminosities (log L = 5.7 L_sun). This is a standard LBV assumption but not directly tested here.
  • domain assumption Chugai & Danziger (1994) mass-loss relation (Eq. 6)
    Empirical relation between shock energy, wind velocity, and mass loss; assumes the observed emission is powered by shock interaction. The efficiency epsilon is uncertain.
  • domain assumption SED blackbody and Kurucz model fits represent photospheric emission
    Used in Section 6.1 to estimate Teff = 33,000 ± 3,000 K. LBVs have winds and excess IR emission; the fit is to dereddened broadband fluxes and two low-resolution spectra, so the inferred temperature is model-dependent.
  • domain assumption The observed He I P Cygni absorption minimum yields the terminal wind velocity
    Used in Section 6.3. The line is weak and partially blended with Na D; the resolution is R~1300, so the velocity measurement (280-300 km/s) is approximate.

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Cite this review

Pith. "Pith review of A Long-term photometric variability and spectroscopic study of luminous blue variable AF And in M31." pith.science (2026). https://pith.science/paper/KNCO3MYK

@misc{pith2026190801893,
  author       = {Pith},
  title        = {Pith review of: A Long-term photometric variability and spectroscopic study of luminous blue variable AF And in M31},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/KNCO3MYK}},
  note         = {Machine review of arXiv:1908.01893}
}
read the original abstract

We present photometric and spectroscopic analysis of the Hubble Sandage variable AF And in M31. The data has been taken under the Nainital Microlensing Survey during 1998-2002 and follow-up observations were carried out until 2011. During this period, photometric observations in Cousins R and I bands were obtained for 169 nights spanning over about 5000 days. AF And has shown a prominent outburst around mid-January in 1999 followed by a gradual decrease in brightness of about 1.5 mag in the next 3 years with a declining rate of ~0.0015 mag/day leading to a quiescent phase at the end of 2001. After lying low for about 9 years, AF And again went through a secondary outburst phase in late 2010 with an amplitude of 0.44 mag where it lasted for one year before fading back to its quiescence phase. The spectroscopic observations of AF And show prominent Balmer and He I emission lines along with the comparatively weaker FeII and [FeII] emissions. Asymmetric emission line profiles in its spectrum imply the mass loss rate of about 2.2x10^{-4} solar mass per yr through the stellar winds in the photosphere. Using SED fitting, we find the photospheric temperature of 33,000+/-3000 K during the visual minimum. Using a weak P Cygni profile of HeI emission line, the wind terminal velocity for AF And is found to be around 280-300 km/s.

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Works this paper leans on

64 extracted references · 63 canonical work pages

  1. [1]

    Ansari, R., Aurière, M., Baillon, P., et al., 2004, A&A, 421, 509

    work page 2004

  2. [2]

    2008, A&A, 492, 277

    Bayo, A., Rodrigo, C., Barrado Y Navascués, D., et al. 2008, A&A, 492, 277

    2008

  3. [3]

    Brown, A. G. A., Vallenari, A., et al., 2018, A&A, 616, 1

    work page 2018

  4. [4]

    G., & Kurucz, R

    Castelli, F., Gratton, R. G., & Kurucz, R. L., 1997, A&A, 318, 841

    work page 1997

  5. [5]

    Chugai, N. N. & Danziger, I. J., 1994, MNRAS, 268, 173

    work page 1994

  6. [6]

    S., Castro, N., Garcia, M., 2012, A&A, 541, 146 Long-term photometric v ariability and spectroscopic study of AF And 15

    Clark, J. S., Castro, N., Garcia, M., 2012, A&A, 541, 146 Long-term photometric v ariability and spectroscopic study of AF And 15

    work page 2012

  7. [7]

    S., 1984, in IAU Symposium, Vol

    Conti, P. S., 1984, in IAU Symposium, Vol. 105, Observationa l Tests of the Stellar Evolution Theory, ed. A. Maeder & A. Renzini, 233

    work page 1984

  8. [8]

    M., et al., 2012, VizieR Online Data Catalog, 2311

    Cutri, R. M., et al., 2012, VizieR Online Data Catalog, 2311

    work page 2012

Show all 64 references
  1. [9]

    J., Bode, M

    Darnley, M. J., Bode, M. F., Kerins, E., et al., 2004, MNRAS, 353, 571 de Koter, A., Lamers, H. J. G. L. M., & Schmutz, W., 1996, A&A, 306, 501 Ekström, S., Georgy, C., & Eggenberger, P., 2012, A&A, 537, 1 46

    2004

  2. [10]

    L., Kewley, L

    Ellison, S. L., Kewley, L. J., & Mallén-Ornelas, G., 2005, MNRAS, 357, 354

    2005

  3. [11]

    L., 1999, PASP, 111, 63

    Fitzpatrick, E. L., 1999, PASP, 111, 63

    1999

  4. [12]

    Fliri, J., Riffeser, A., Seitz, S., & Bender, R., 2006, A&A, 44 5, 423

    2006

  5. [13]

    J., 1996, ApJ, 469, 355

    Flower, P. J., 1996, ApJ, 469, 355

    1996

  6. [14]

    L, Madore, B

    Freedman, W. L, Madore, B. F., Gibson, B. K., et al., 2001, ApJ , 553, 47

    2001

  7. [15]

    S., Kenyon, S

    Gallagher, J. S., Kenyon, S. J., & Hege, E. K., 1981, ApJ, 249, 83

    1981

  8. [16]

    M., 1997, in Astronomical Society of the Pacific Conference Series, Vol

    Garcia-Segura, G., Langer, N., & Mac Low, M. M., 1997, in Astronomical Society of the Pacific Conference Series, Vol. 120, Luminous Blue Variables: Massive Stars in Transition, ed. A. Nota & H. Lamers, 332

    1997

  9. [17]

    H., Hillier, D

    Groh, J. H., Hillier, D. J., Damineli, A., et al., 1993, ApJ, 6 98, 1698

    1993

  10. [18]

    & Sandage, A

    Hubble, E. & Sandage, A. 1953, ApJ, 118, 353

    1953

  11. [19]

    M., 1975, ApJ, 200, 426

    Humphreys, R. M., 1975, ApJ, 200, 426

    1975

  12. [20]

    M., 1978, ApJ, 219, 445

    Humphreys, R. M., 1978, ApJ, 219, 445

    1978

  13. [21]

    Humphreys, R. M. & Davidson, K., 1994, PASP, 106, 1025

    1994

  14. [22]

    M., W eis, K., Davidson, K., & Gordon, M

    Humphreys, R. M., W eis, K., Davidson, K., & Gordon, M. S., 2016, ApJ, 825, 64

    2016

  15. [23]

    C., Pandey, A

    Joshi, Y. C., Pandey, A. K., Narasimha, D., & Sagar, R., 2001, BASI, 29, 531

    2001

  16. [24]

    C., Pandey, A

    Joshi, Y. C., Pandey, A. K., Narasimha, D., Sagar, R., & Giraud-Héraud, Y., 2003, A&A, 402, 113

    2003

  17. [25]

    C., Pandey, A

    Joshi, Y. C., Pandey, A. K., Narasimha, D., et al., 2004, A&A, 415, 471

    2004

  18. [26]

    C., Pandey, A

    Joshi, Y. C., Pandey, A. K., Narasimha, D., & Sagar, R., 2005, A&A, 433, 787

    2005

  19. [27]

    C., Narasimha, D., Pandey, A

    Joshi, Y. C., Narasimha, D., Pandey, A. K., & Sagar, R., 2010, A&A, 512, 66

    2010

  20. [28]

    Joshi, Y. C. & Narasimha, D., 2012, BASI, 40, 459

    2012

  21. [29]

    C., Jagirdar, R., 2017, RAA, 17, 115

    Joshi, Y. C., Jagirdar, R., 2017, RAA, 17, 115

    2017

  22. [30]

    Y., W est, A

    Kesseli, A. Y., W est, A. A., Veyette, M., et al., 2017, ApJS, 2 30, 16

    2017

  23. [31]

    Kewley, L. J. & Dopita, M. A., 2002, ApJS, 142, 35

    2002

  24. [32]

    & Vink, J

    Kotak, R. & Vink, J. S., 2006, A&A, 460, L5

    2006

  25. [33]

    Fernande, M., 2014, ApJ, 780, L10

    2014

  26. [34]

    G., Corral, L

    Kurtev, R. G., Corral, L. J., & Georgiev, L., 1999, A&A, 349, 7 96

    1999

  27. [35]

    R., Lennon, M., et al., 1994, A&A, 290, 819

    Langer, N., Hamann, W. R., Lennon, M., et al., 1994, A&A, 290, 819

    1994

  28. [36]

    Langer, N., García-Segura, G., & Mac Low, M.-M., 1999, ApJL, 520, L49

    1999

  29. [37]

    Lee, C.-H., Riffeser, A., Koppenhoefer, J., et al., 2012, AJ, 143, 89

    2012

  30. [38]

    Lee, C.-H., Seitz, S., Kodric, M., et al., 2014, ApJ, 785, 11

    2014

  31. [39]

    Leitherer, C., Allen, R., Altner, B., et al., 1994, ApJ, 428, 292

    1994

  32. [40]

    J., 1928, Harvard College Observatory Bulletin, 859, 1

    Luyten, W. J., 1928, Harvard College Observatory Bulletin, 859, 1

    1928

  33. [41]

    Massey, P., Olsen, K. A. G., Hodge, P. W., et al., 2006, AJ, 131 , 2478

    2006

  34. [42]

    S., 1991, ApJ, 380, 140

    McGaugh, S. S., 1991, ApJ, 380, 140

    1991

  35. [43]

    Meynet, G., Georgy, C., Hirschi, R., et al., 2011, Bulletin d e la Societe Royale des Sciences de Liege, 80, 266

    2011

  36. [44]

    R., de Koter, A., Evans, C

    Mokiem, M. R., de Koter, A., Evans, C. J., et al., 2007, A&A, 465, 1003

    2007

  37. [45]

    & van Marle, A

    Owocki, S. & van Marle, A. J., 2008, in IAU Symposium, Vol. 250, Massive Stars as Cosmic Engines, ed. F. Bresolin, P. A. Crowther, & J. Puls, 71–82

    2008

  38. [46]

    & Pagel, B

    Pettini, M. & Pagel, B. E. J., 2004, MNRAS, 348, L59

    2004

  39. [47]

    Pilyugin, L. S. & Thuan, T. X., 2005, ApJ, 631, 231

    2005

  40. [48]

    Prusti, T., de Bruijne, J. H. J., et al., 2016, A&A, 595, 1

    2016

  41. [49]

    E., Caldwell, N., McDowell, J., & Harding, P., 20 12, ApJ, 758, 133 Schlafly, E

    Sanders, N. E., Caldwell, N., McDowell, J., & Harding, P., 20 12, ApJ, 758, 133 Schlafly, E. F. & Finkbeiner, D. P., 2011, ApJ, 737, 103

    2011

  42. [50]

    J., Finkbeiner, D

    Schlegel, D. J., Finkbeiner, D. P., & Davis, M., 1998, ApJ, 50 0, 525

    1998

  43. [51]

    S., 1990, Soviet Ast., 34, 364

    Sharov, A. S., 1990, Soviet Ast., 34, 364

    1990

  44. [52]

    N., Fabrika, S

    Sholukhova, O. N., Fabrika, S. N., Zharova, A. V., Valeev, A. F., & Goranskij, V. P., 2011, AstBu, 66, 123

    2011

  45. [53]

    Sholukhova, O., Bizyaev, D., Fabrika, S., et al., 2015, MNRA S, 447, 2459

    2015

  46. [54]

    F., Cutri, R

    Skrutskie, M. F., Cutri, R. M., Stiening, R., et al., 2006, AJ , 131, 1163

    2006

  47. [55]

    J., Crowther, P

    Smith, L. J., Crowther, P. A., & Prinja, R. K., 1994, A&A, 281, 833

    1994

  48. [56]

    D., Hinz, M., et al., 2003, ApJL, 125, 145 8

    Smith, N., Gehrz, R. D., Hinz, M., et al., 2003, ApJL, 125, 145 8

    2003

  49. [57]

    & Owocki, S

    Smith, N. & Owocki, S. P., 2006, ApJL, 645, L45

    2006

  50. [58]

    & McCray, R., 2007, ApJL, 671, L17

    Smith, N. & McCray, R., 2007, ApJL, 671, L17

    2007

  51. [59]

    V., 2011, MNRAS, 415, 773

    Filippenko, A. V., 2011, MNRAS, 415, 773

    2011

  52. [60]

    & Tombleson, R., 2015, MNRAS, 447, 598

    Smith, N. & Tombleson, R., 2015, MNRAS, 447, 598

    2015

  53. [61]

    Solovyeva, Y., Vinokurov, A., & Fabrika, S., 2019, MNRAS, 48 4, 24 Soszyński, I., Pawlak, M., Pietrukowicz, P., et al., 2016, A cta Astron., 66, 405

    2019

  54. [62]

    G., & McCall, M

    Stahl, O., Jankovics, I., Kovács, J., et al., 2001, A&A, 375, 54 Stasińska, G., Richer, M. G., & McCall, M. L., 1998, A&A, 336, 667

    2001

  55. [63]

    M., Davidson, K., et al., 1996, A &A, 314, 131 W olf, B., 1989, A&A, 217, 87

    Szeifert, T., Humphreys, R. M., Davidson, K., et al., 1996, A &A, 314, 131 W olf, B., 1989, A&A, 217, 87

    1996

  56. [64]

    G., Adelman, J., Anderson, Jr., J

    York, D. G., Adelman, J., Anderson, Jr., J. E., et al., 2000, A J, 120, 1579

    2000

Pith tools

Reviewed August 14, 2026 · model on record in the stance chip above.