Pith. sign in

REVIEW 3 major objections 6 minor 37 references

The proto-planetary nebula Hen 3-1475 may have ejected a new jet between 2006 and 2024, while its central star remains too cool to ionize the surrounding gas.

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 03:42 UTC pith:UM7MRI5N

load-bearing objection Solid two-epoch spectroscopic study; the no-photoionization result holds, but the claimed new jet rests on unmatched apertures and needs same-instrument follow-up. the 3 major comments →

arxiv 2607.23061 v1 pith:UM7MRI5N submitted 2026-07-25 astro-ph.SR

High-resolution spectroscopy of the bipolar proto-planetary nebula Hen 3-1475, the Garden Sprinkler Nebula

Ana Valeria Beltr\'an-S\'anchez , Miriam Pe\~na , Mudumba Parthasarathy This is my paper
classification astro-ph.SR
keywords Hen 3-1475proto-planetary nebulaP-Cygni profilesstellar windsjetsshocked gaspost-AGB starsspectroscopy
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.

Hen 3-1475, a proto-planetary nebula shaped like a garden sprinkler, sits between the dying-star and planetary-nebula phases. This paper compares high-resolution optical spectra of its central region taken in 2006 and 2024 to find out whether the central star has become hot enough to ionize the nebula and whether the source's emission is changing on human timescales. The authors find that the star still falls short: no photoionized nebular lines such as [O III] 5007 appear in either epoch, placing the effective temperature below about 30,000 K. The biggest change is new: in 2024 the forbidden oxygen lines [O I] at 6300/6363 Å appear as double components separated by about 60 km/s, and a broad component appears next to Hα at 6580 Å; neither was seen in 2006, suggesting a new jet has been ejected from the central zone. They also report that the bright knot NW1 has lost its [O III] 5007 emission, implying its shock has slowed or the gas has recombined within the last two decades.

Core claim

In the authors' reading, the 2024 spectra show emission that was not present in 2006: two components of the [O I] 6363 Å (and 6300 Å) lines separated by roughly 60 km/s, and a broad feature at about 6580 Å adjacent to Hα. They interpret this as a probable new jet emerging from the central star, with the 6580 Å component representing jet emission at more than 700 km/s. At the same time, neither epoch shows photoionized nebular lines like [O III] 5007, so the central star's effective temperature has not yet reached about 30,000 K; the nebula remains neutral and shock-excited rather than photoionized. The spectra are dominated by stellar P-Cygni profiles in the H Balmer series, Fe II, Ca II, Na

What carries the argument

The analysis rests on comparing emission-line profiles from high-resolution echelle spectra of the central zone at two epochs (2006 and 2024). The load-bearing diagnostics are the P-Cygni profiles that trace stellar wind terminal velocities (up to ~800 km/s); the [O I] 6300/6363 doublet, whose shape and multiplicity reveal shocked gas and, in 2024, splits into two components ~60 km/s apart; a broad Hα-adjacent feature at ~6580 Å attributed to a fast jet; and the complete absence of photoionized lines such as [O III] 5007, which sets an upper limit on the central star's effective temperature. The constant measured systemic velocity (~39.4–39.6 km/s) between epochs is used to argue against a c

Load-bearing premise

The 2024 double [O I] components and the broad 6580 Å feature are treated as new emission from a newly ejected jet, but they were detected with a different spectrograph, different slit widths, and slightly different pointing than the 2006 data, so they could be artifacts of aperture, seeing, or scattered light rather than genuine new outflow.

What would settle it

Re-observe the central zone with the same spectrograph and aperture setup used in 2006 (or with a matched fiber/slit configuration) and at multiple position angles; if the ~60 km/s double [O I] separation and the 6580 Å broad component disappear or change with aperture, they are artifacts, whereas if they persist with stable kinematics and a corresponding knot appears in deep imaging along the jet axis, the new-jet claim is supported.

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

If this is right

  • If the new [O I] components and the 6580 Å feature are genuine, the object has ejected a new jet within the last 18 years, while still in its pre-ionization proto-planetary phase.
  • The central star remains below about 30,000 K, so the nebula is still neutral and shock-dominated; any earlier claims of photoionization (e.g., from the 12.8 µm [Ne II] detection) are better explained by shocks.
  • The identical radial velocity in 2006 and 2024 makes a close binary companion less likely, complicating binary-based jet-collimation scenarios for this source.
  • The disappearance of [O III] 5007 from knot NW1 means shocked knots in this object can change their ionization state on timescales of a couple of decades, either through shock deceleration below 50 km/s or fast recombination of dense gas.

Where Pith is reading between the lines

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

  • If confirmed as a new ejection, the jet's ~60 km/s velocity separation is far slower than the historic 1200–2300 km/s jets of this object, suggesting a weaker or differently oriented ejection event that imaging in the next few years could verify by looking for a new knot along the point-symmetric axis.
  • Because the broad 6580 Å feature was most prominent in the widest-slit observation, it may trace a more extended outflow cavity; integral-field spectroscopy would clarify whether it is a separate jet or merely scattered/outflowing gas projected along the line of sight.
  • The fading of [O III] in NW1 predicts that the rest of the S-shaped string of knots should also be losing their high-ionization lines; a single deep spectrum of the full string taken in the next few years would confirm a global decline of shock excitation.
  • The unchanged systemic velocity only rules out close, edge-on orbits; a longer-period or nearly face-on companion remains possible, so the binarity question needs photometric or astrometric monitoring rather than spectroscopy alone.

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

3 major / 6 minor

Summary. This paper presents high-resolution optical/near-IR spectra of the central region of the proto-planetary nebula Hen 3-1475, obtained in 2006 with FEROS and in 2024 with REOSC, together with 2024 spectra of the knot NW1. The authors identify a very rich spectrum of stellar and nebular lines (H I, He I, Fe II, [Fe II], O I, Ca II, [Ca II], etc.), measure P-Cygni profiles and terminal wind velocities up to ~800 km/s, and use [Fe II] and Fe I as density indicators. They find no photoionized nebular lines such as [O III], [N II], or [S II] in either epoch and conclude that the central star has not yet become hot enough to photoionize the nebula. A comparison between 2006 and 2024 leads them to claim a probable new jet in the central zone, seen as a double [O I] 6363 component and a broad feature adjacent to Hα, as well as changes in the NW1 knot (loss of [O III] 5007 and other lines).

Significance. The paper provides the most complete optical line list of Hen 3-1475 to date (Table 4, ~500 lines), making it a useful reference for future studies of this important post-AGB object. The main conclusion that the central star is still below the threshold for photoionization is observationally well supported by the consistent absence of [O III], [N II], and [S II] in both epochs, and it has implications for the evolutionary status of the source. The authors are appropriately cautious in several places (e.g., in the O I 8446 discussion and in pointing out possible slit-position effects for NW1). However, the headline claim of a new jet is not yet established because the two epochs were observed with different spatial apertures; this is a load-bearing issue for the paper's main 'change' claim.

major comments (3)
  1. [§5, Fig. 10, §2.1–2.2] The claimed new jet in the central zone rests on a comparison of non-identical apertures. FEROS used a 2″ circular fiber, whereas the 2024 REOSC spectra were extracted over a 2″×5″ window (and one night used a 7″ slit). The 2024 extraction can therefore include extended [O I]-emitting regions that the FEROS fiber never sampled. The authors themselves note (§5) that the broad Hα component is most prominent on the wide-slit night and that slit-width variations allowed detection of additional features. A synthetic-aperture re-extraction of the 2024 frames matching the FEROS footprint, or a quantitative comparison of the 2″ and 7″ nights, is required to distinguish a genuinely new jet from pre-existing extended emission. As written, the headline temporal-difference claim is not established.
  2. [§6, Table 3, Fig. 11] The 6580 Å feature in NW1 is listed as 'Hα jet/[NII]?' and is used in the conclusions to support a jet at >700 km/s. However, NW1 has no 2006 observation; the only previous epoch is 1999 STIS (Riera et al. 2006), with a different slit and extraction. The identification of the 6580 Å feature itself is uncertain—it is 17 Å redward of Hα, which at R≈18000 is resolved, but without a secure identification or a 2006 baseline it cannot be claimed as a new jet component. At most it is a feature seen in 2024 in one knot; the label 'Hα jet/[NII]?' should either be made secure with supporting diagnostics or presented as an unidentified feature.
  3. [§3, §7] The central claim that the star has not ionized the nebula is based on non-detections of [O III] 5007, [N II] 6583, and [S II] 6716,6731 in both epochs. No flux upper limits or detection thresholds are given for these lines. Given that the paper otherwise reports many weak lines, the non-detections are probably meaningful, but the claim would be on firmer ground if the authors provided 3σ upper limits and stated the S/N in the relevant spectral regions.
minor comments (6)
  1. [§6] The GAIA distance is given as '5.32 pc'; the correct value is 5.32 kpc. The knot size of '1.29×10^-5 pc' appears to be off by three orders of magnitude (0.5 arcsec at 5.32 kpc corresponds to ~1.3×10^-2 pc).
  2. [Table 3] The label 'Hα jet/[NII]?' should be clarified: if the feature is Hα at ~700 km/s, specify the velocity and whether the corresponding blueshifted [N II] 6548 component is present; if it is [N II] 6583, the apparent velocity differs from that of Hα.
  3. [§2.1] Please state explicitly that FEROS uses a 2″ circular fiber for the object beam; the current text implies it but does not say it clearly, which is important for the aperture-comparison discussion.
  4. [Table 4] Many entries have '?' or 'P-Cygni?' with no explanation. A brief note on line-identification confidence criteria would help the reader interpret these uncertain identifications.
  5. [Appendix B] The 'Second Appendix' section appears to be an empty placeholder; it should be removed or filled with content.
  6. [General] The text contains numerous spacing/OCR artifacts (e.g., 'P-Cygniprofiles', 'García-Seguraetal.', 'Hαjet/[NII]?'). A careful proofreading pass is needed before publication.

Circularity Check

0 steps flagged

No circularity: the paper is an observational epoch comparison with no fitted model or self-derived benchmark.

full rationale

The paper's central claims are direct observational comparisons: new [O I] double components at 6363.9/6365.1 Å in 2024 vs. a single component in 2006 FEROS data, and a broad Hα feature at ~6580 Å. These are empirical detections based on spectra, not outputs of a model fitted to the object. The paper contains no fitted parameters that are then renamed as predictions, and no derivation chain in which an assumed quantity reappears as a conclusion. The O I 8446 Å fluorescence interpretation is explicitly held despite a null test (no O I 1304 Å detection), with the paper stating the UV result is 'not conclusive' and that absence 'does not invalidate the fluorescencescenario'—this is conservative handling of evidence, not circular reasoning. The self-citations (Parthasarathy & Pottasch 1989 for classification; Parthasarathy et al. 2000 for Balmer P-Cygni; Gauba & Parthasarathy 2003 for UV obscuration) establish historical context and are not load-bearing for the new-jet or temperature conclusions. The NW1 comparison uses external, independent STIS data from Riera et al. (2006), and the paper explicitly acknowledges the lack of 2006 NW1 observations ('we have no observations of the knot NW1 in 2006 to compare'). The main potential weakness—non-identical apertures between the 2006 FEROS fiber and the 2024 REOSC slits—is an observational systematic effect, not circularity; the paper itself notes that the wider slit allowed detection of broader emission. Thus there is no step that reduces by definition or by self-citation to its own inputs.

Axiom & Free-Parameter Ledger

0 free parameters · 5 axioms · 0 invented entities

No free parameters are fitted to data. The conclusions rest on standard spectral diagnostics plus two fragile interpretive assumptions: negative detection implies T_eff < 30,000 K, and cross-instrument comparability implies the temporal changes are real.

axioms (5)
  • domain assumption Line identifications and rest wavelengths in Table 4 are correct (standard atomic data).
    Many entries are marked '?' and some blends are acknowledged; a wrong identification would shift terminal velocities and density interpretations.
  • domain assumption P-Cygni absorption troughs trace the stellar wind terminal velocity.
    Used throughout §3 and Table 2; assumes the absorption at maximum velocity is unblended and formed in the wind.
  • domain assumption The absence of [O III] λ5007 and other high-ionization forbidden lines implies T_eff < 30,000 K.
    Section 7; assumes an ionized region would fall within the slit and be detectable despite extinction and aperture effects.
  • domain assumption Distance D = 5.8 ± 0.9 kpc from Riera et al. 2003 is used for physical scales.
    Used to convert angular sizes to pc; the GAIA parallax (0.3145 ± 0.3048 mas) is too uncertain to replace this value.
  • domain assumption The 2024 slit positions reproduce the 1999/2006 sampled regions of the central zone and NW1.
    Required for temporal comparisons; the paper states no 2006 NW1 observation exists and slit widths/orientations varied in 2024.

pith-pipeline@v1.3.0-alltime-deepseek · 32593 in / 17237 out tokens · 179329 ms · 2026-08-01T03:42:39.713504+00:00 · methodology

0 comments
read the original abstract

A detailed analysis of high-resolution spectra in the optical and near-infrared range of the central zone of the proto-planetary nebula Hen 3-1475, obtained in 2006 and 2024, is conducted. The spectrum primarily revealed stellar emission of H Balmer and Paschen series, lines of iron (Fe I, Fe II, and [Fe II]), and other significant lines of He I, Ca II, [Ca II], and O I. Several multiplets of Fe II, the H Balmer series, Ca II H and K, Na I D and He I lines exhibit P-Cygni profiles and bump-like features, which are clear indicators of strong stellar winds. The terminal velocity of the winds was calculated, reaching values up to ~ 800 km/s. [Fe II] and Fe I lines were used as gas density indicators. In these observations, no photoionized nebular lines of planetary nebulae were identified, suggesting that the central star has not reached the temperature required to photoionize the nebula. A comparison between the observations from 2006 and 2024 reveals some few significant differences, being the most important the probably ejection of a new jet emerging from the central zone and the detection of a broad component adjacent to H \alpha, probably originating from emission associated with a jet at 700 km/s. High-spectral resolution observations of the knot NW1 obtained on August 2024, are also presented. This knot shows a typical spectrum of shocked gas. The emission of this knot has changed, presently not showing [O III] 5007 and other ionized lines that were reported in 2006.

Figures

Figures reproduced from arXiv: 2607.23061 by Ana Valeria Beltr\'an-S\'anchez, Miriam Pe\~na, Mudumba Parthasarathy.

Figure 1
Figure 1. Figure 1: Balmer series lines (H 𝛼, H 𝛽, H 𝛾, H 𝛿 and H 8) from 2006 observations. H 𝜖 is missing due to blending with a calcium line. The black dotted lines indicate the continuum making clear the P-Cygni profile. already become hot enough to ionize the surrounding gas, as they detected the nebular emission line [Ne II] at 12𝜇m. In their paper and in Borkowski & Harrington (2001) it is suggested that Hen 3- 1475 is… view at source ↗
Figure 2
Figure 2. Figure 2: Hubble Space Telescope (HST) F658N images of Hen 3-1475 obtained in 1999 (red) and 2009 (green) presented by Fang et al. (2018) along with OAN-SPM slit orientations for observations (performed in 2024) of the center (purple) and NW1 knot (yellow). The slits are 2 arcsec wide and 13 arcsec long, and some are oriented from E to W and others from N to S. 2. OBSERVATIONS Two sets of observations, obtained at d… view at source ↗
Figure 3
Figure 3. Figure 3: Fe II from multiplet 42. calculated using the wavelength corresponding to this maximum velocity. However, since the exact rest wavelength is unclear due to contributions from different parts of the object to the emission, the systemic velocity was used as a reference. This systemic velocity was calculated as the average value determined from emission lines without P-Cygni profiles, giving a result of 𝑣LSR … view at source ↗
Figure 4
Figure 4. Figure 4: (a) He I 𝜆4471 bump and an unidentified line with P-Cygni profile, most likely corresponding to Mg II.(b) Bump + P-Cygni profile in the He I 𝜆4713 line. (c) He I 𝜆5876 bump and the Na I D lines showing P-Cygni profile. (d) P-Cygni profile observed in the He I 𝜆6678 line. besides those exhibiting P-Cygni profiles. From each of these, at least two emission lines are detected. These multiplets include #s 3, 2… view at source ↗
Figure 5
Figure 5. Figure 5: The O I 8446 Å emission observed corresponds to a triplet consisting of the lines at 8446.25 Å, 8446.36 Å, and 8446.76 Å. emissions resembling a bump. It is important to note that He I lines belong to two different families. When ionized helium recombines, the captured electron can have either parallel or anti-parallel spin relative to the spin of the electron present in the level, leading to triplet and s… view at source ↗
Figure 7
Figure 7. Figure 7: Zoom-in of the STIS UV spectrum obtained in 2015. The red dotted line indicates the expected position of the O I 1302 Å line, while the blue dotted line marks the peak of an unidentified line at ∼1338 Å. medium. In this work, we derived a ratio of 0.86 for the Ca lines; this implies a still optically thick region where Ca II lines are forming. According to Persson et al. (1988) this also implies a hydrogen… view at source ↗
Figure 8
Figure 8. Figure 8: (a) P-Cygni profile in Ca II H and K lines and H 𝜖, the wing coming from Ca II H and H 𝜖 blends. (b) Intense Ca II lines in the IR [PITH_FULL_IMAGE:figures/full_fig_p008_8.png] view at source ↗
Figure 9
Figure 9. Figure 9: Superposition of H𝛼 emission from different nights at OAN-SPM 2024 and the FEROS 2006 observation. A difference of 94 km s −1 between both epochs, possibly due to differences in the stellar wind, is found. emission lies in the middle of 2024 emissions at a wavelength corresponding with the system velocity. Notably, the study by Riera et al. (1995), which employed a slit width of 1.5 arcsec, did not report … view at source ↗
Figure 11
Figure 11. Figure 11: H 𝛼 emission from observations of knot NW1 and jet emission [PITH_FULL_IMAGE:figures/full_fig_p009_11.png] view at source ↗
Figure 12
Figure 12. Figure 12: Double-peaked profile of the [O I] 6363 Å emission line originating from the knot NW1. emission from the shocked lines such as [S II] 𝜆𝜆6716 and 6731 and [O I]𝜆𝜆6300 and 6364, all of which present a double peak, as shown in [PITH_FULL_IMAGE:figures/full_fig_p009_12.png] view at source ↗
Figure 13
Figure 13. Figure 13: FEROS spectrum obtained in 2006, in the range from 3800 to 9200 Å, normalized to the continuum. The strongest lines have been marked. 121 [PITH_FULL_IMAGE:figures/full_fig_p012_13.png] 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

37 extracted references · 11 canonical work pages

  1. [1]

    , keywords =

    HST STIS UV Spectroscopic Observations of the Protoplanetary Nebula Hen3-1475. , keywords =. doi:10.3847/2041-8213/aae20c , archivePrefix =. 1810.00634 , primaryClass =

    Pith/arXiv arXiv 2041

  2. [2]

    , keywords =

    Observations of southern emission-line stars. , keywords =. doi:10.1086/190369 , adsurl =

    doi:10.1086/190369

  3. [3]

    The young planetary nebula IC 4997

    A many-year photometric and spectroscopic variability study of planetary nebulae (1968-2008). The young planetary nebula IC 4997. Astronomy Reports , year = 2009, month = dec, volume =. doi:10.1134/S1063772909120087 , adsurl =

    work page doi:10.1134/s1063772909120087 1968

  4. [4]

    , keywords =

    IRAS 17423-1755: a massive post-AGB star evolving into the planetary nebula stage?. , keywords =

  5. [5]

    , keywords =

    The far-infrared (IRAS) excess in BQ and related stars. , keywords =

  6. [6]

    , keywords =

    X-Ray Emission from the Pre-planetary Nebula Henize 3-1475. , keywords =. doi:10.1086/381316 , archivePrefix =. astro-ph/0312130 , primaryClass =

    Pith/arXiv arXiv

  7. [7]

    , keywords =

    A 2000 Kilometer per Second ``Pristine'' Post-asymptotic Giant Branch Wind in the Proto-planetary Nebula He 3-1475. , keywords =. doi:10.1086/320687 , adsurl =

    work page doi:10.1086/320687 2000

  8. [8]

    , keywords =

    An OH survey of very cold IRAS point sources. , keywords =

  9. [9]

    , keywords =

    Bipolar outflows in OH/IR stars. , keywords =. doi:10.1046/j.1365-8711.2001.04113.x , archivePrefix =. astro-ph/0010602 , primaryClass =

    arXiv 2001

  10. [10]

    , keywords =

    Time-dependent ejection velocity model for the outflow of <ASTROBJ>Hen 3-1475</ASTROBJ>. , keywords =. doi:10.1051/0004-6361:20035757 , archivePrefix =. astro-ph/0403126 , primaryClass =

    Pith/arXiv arXiv

  11. [11]

    , keywords =

    Shock excitation of the knots of Hen 3-1475. , keywords =. doi:10.1051/0004-6361:20053499 , archivePrefix =. astro-ph/0605257 , primaryClass =

    Pith/arXiv arXiv

  12. [12]

    , keywords =

    The high-velocity outflow in the proto-planetary nebula Hen 3-1475. , keywords =. doi:10.1051/0004-6361:20030199 , archivePrefix =. astro-ph/0303111 , primaryClass =

    Pith/arXiv arXiv

  13. [13]

    , year = 2005, month = sep, volume =

    Evolution of Asymptotic Giant Branch Stars. , year = 2005, month = sep, volume =. doi:10.1146/annurev.astro.43.072103.150600 , adsurl =

    Pith/arXiv arXiv 2005

  14. [14]

    , keywords =

    Optical Polarization and Near-Infrared Photometry of the Proto-planetary Nebula Henize 3-1475. , keywords =. doi:10.1086/368073 , archivePrefix =. astro-ph/0212435 , primaryClass =

    Pith/arXiv arXiv

  15. [15]

    , keywords =

    Spectroscopy of the post-AGB star HD 101584 (IRAS 11385-5517). , keywords =. doi:10.1051/aas:1999259 , archivePrefix =. astro-ph/9907310 , primaryClass =

    Pith/arXiv arXiv

  16. [16]

    , keywords =

    Kinematics of 1200 Kilometer per Second Jets in HE 3-1475. , keywords =. doi:10.1086/319812 , adsurl =

    work page doi:10.1086/319812

  17. [17]

    , keywords =

    Radio-Frequency Continuum Emission from Evolved Stars. , keywords =. doi:10.1086/176577 , adsurl =

    work page doi:10.1086/176577

  18. [18]

    , keywords =

    Mass, linear momentum and kinetic energy of bipolar flows in protoplanetary nebulae. , keywords =. doi:10.1051/0004-6361:20011090 , adsurl =

    doi:10.1051/0004-6361:20011090

  19. [19]

    , keywords =

    Echelle Long-Slit Optical Spectroscopy of Evolved Stars. , keywords =. doi:10.1086/591273 , archivePrefix =. 0806.4474 , primaryClass =

    Pith/arXiv arXiv

  20. [20]

    , keywords =

    High Spatial and Spectral Resolution Observations of the Optical Counterparts of GL 490 and S106/IRS 3. , keywords =. doi:10.1086/166096 , adsurl =

    work page doi:10.1086/166096

  21. [21]

    , keywords =

    The Proto-Planetary Nebula M1-92 and the Symbiotic Star MWC 560: Two Evolutionary Phases of the Same Type of Object?. , keywords =. doi:10.1086/428391 , adsurl =

    work page doi:10.1086/428391

  22. [22]

    , keywords =

    IRAS 17423-1755 (Hen 3-1475) Revisited: An O-rich High-mass Post-asymptotic Giant Branch Star. , keywords =. doi:10.1088/0004-6256/141/3/80 , adsurl =

    work page doi:10.1088/0004-6256/141/3/80

  23. [23]

    , keywords =

    UV(IUE) spectra of hot post-AGB candidates. , keywords =. doi:10.1051/0004-6361:20030996 , adsurl =

    work page doi:10.1051/0004-6361:20030996

  24. [24]

    Southern Spectrophotometric Standards. I. , keywords =. doi:10.1086/133028 , adsurl =

    doi:10.1086/133028

  25. [25]

    Spectral properties of galaxies

    Spectral analysis of the Stromlo-APM Survey - I. Spectral properties of galaxies. , keywords =. doi:10.1046/j.1365-8711.1999.02977.x , archivePrefix =. astro-ph/9905384 , primaryClass =

    arXiv 1999

  26. [26]

    From protoplanetary to planetary nebula

    Common-envelope shaping of planetary nebulae - IV. From protoplanetary to planetary nebula. , keywords =. doi:10.1093/mnras/stac2824 , archivePrefix =. 2209.15081 , primaryClass =

    Pith/arXiv arXiv

  27. [27]

    , keywords =

    On the presence of OI lambda 1302 emission in Be stars. , keywords =. doi:10.1086/131136 , adsurl =

    work page doi:10.1086/131136

  28. [28]

    , keywords =

    Low resolution spectroscopy of hot post-AGB candidates. , keywords =. doi:10.1051/aas:2000242 , adsurl =

    work page doi:10.1051/aas:2000242

  29. [29]

    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

  30. [30]

    Carrasco, J. M. and Weiler, M. and Jordi, C. and Fabricius, C. and De Angeli, F. and Evans, D. W. and van Leeuwen, F. and Riello, M. and Montegriffo, P. , year=. Internal calibration of Gaia BP/RP low-resolution spectra , volume=. doi:10.1051/0004-6361/202141249 , journal=

    doi:10.1051/0004-6361/202141249

  31. [31]

    Information content of BP/RP spectra in Gaia DR3 , volume=

    Witten, Callum E C and Aguado, David S and Sanders, Jason L and Belokurov, Vasily and Evans, N Wyn and Koposov, Sergey E and Allende Prieto, Carlos and De Angeli, Francesca and Irwin, Mike J , year=. Information content of BP/RP spectra in Gaia DR3 , volume=. Monthly Notices of the Royal Astronomical Society , publisher=. doi:10.1093/mnras/stac2273 , number=

    work page doi:10.1093/mnras/stac2273

  32. [32]

    2025 , eprint=

    ALMA observations of CO isotopologues towards six obscured post-AGB stars , author=. 2025 , eprint=

    2025

  33. [33]

    , keywords =

    OI lambda 8446 emission in Seyfert 1 galaxies. , keywords =. doi:10.1086/157952 , adsurl =

    doi:10.1086/157952

  34. [34]

    , keywords =

    1-2.5 mu m spectra of jets from young stars: Strong Fe II emission in HH111, HH240-241 and HH120. , keywords =. doi:10.1051/0004-6361:20021062 , adsurl =

    doi:10.1051/0004-6361:20021062

  35. [35]

    The Astronomical Review , keywords =

    Low Ionization Emission Lines in Quasars. The Astronomical Review , keywords =. doi:10.1080/21672857.2013.11519727 , archivePrefix =. 1311.1529 , primaryClass =

    arXiv 2013

  36. [36]

    , keywords =

    Planetary Nebulae: Sources of Enlightenment. , keywords =. doi:10.1088/1538-3873/ac32b1 , archivePrefix =. 2110.13993 , primaryClass =

    Pith/arXiv arXiv

  37. [37]

    Astrophysics of gaseous nebulae and active galactic nuclei