Detection of an Extrasolar Planet Atmosphere
The Astrophysical Journal, 2002 · paper · Astronomy
Reports Hubble Space Telescope observations of four transits of HD 209458, finding extra dimming in the sodium wavelength band, interpreted as sodium in the planet's atmosphere. The absorption is weaker than a cloudless solar-abundance model predicts.
Checked: PDF from arxiv.org, fetched 4 Oct 2026. Page numbers are those of that PDF.
4 findings
Substance "This leaves 417 spectra of the 684 acquired" and "There are 171 in-transit observations, and 207 out-of-transit observations. We ignore the small fraction (7%) of observations that occur during ingress or egress": 417 - 171 - 207 = 39 observations, which is 9.4% of 417, not 7%.
- p. 4 Section 2, top of page
fraction (7%) of observations that occur during ingress or egress
- p. 4 Section 2, top of page
There are 171 in-transit observations, and 207 out-of-transit observations.
- p. 3 Section 2, fourth paragraph
This leaves 417 spectra of the 684 acquired.
- p. 4 Section 2, top of page
There are 171 in-transit observations, and 207 out-of-transit observations. We ignore the small fraction (7%) of observations that occur during ingress or egress.
Only the authors can say what is right here.
Judge's note: Read the numbers on the p3 and p4 page images: 417, 684, 171, 207 and 7% are printed as quoted. 39/417 = 9.4%; against the 684 acquired it is 5.7%, and against 513 (three visits of 171) it is 7.6%, so no stated base gives 7%. Searched the text for another base or a further exclusion and found none; the Figure 4 caption (10 bins of about 42 observations) agrees with about 417 points in the series. The errors in equation (5) are reproduced by 171 and 207, so those counts look sound; whether 417 or 7% is the misprint only the authors can say.
Second check: another model agreed
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Reference or label The text cites "Queloz et al. 2000b" (Section 4.2) and "Queloz et al. 2000" (Introduction), but the reference list has two Queloz 2000 entries, "S. 2000, A&A, 359, L13" and "Queloz, D. et al. 2000, A&A, 354, 99", neither carrying an a or b.
- p. 10 Section 4.2, first paragraph of page
(Queloz et al. 2000b; Butler et al. 2000)
- p. 2 Introduction, first paragraph
(Queloz et al. 2000; Bundy & Marcy 2000)
- p. 13 Reference list
Queloz, D. et al. 2000, A&A, 354, 99
- p. 13 Reference list
S. 2000, A&A, 359, L13
Judge's note: Read the citations in the text for p2 and on the p10 image, and the reference list on the p13 image. Two Queloz 2000 entries, no suffixes; there is no '2000a' anywhere in the text. A reader cannot tell from the paper which entry each citation means. The fix is to label the entries a and b and add the letter to the Introduction citation; the authors must confirm which is which.
Second check: another model agreed
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Reference or label Section 3: "most of the models listed in Table 1 produce differential transits that are significantly deeper than our observational result"; the models are listed in Table 2 ("Model Atmosphere Parameters"), and Table 1 is "Wavelength Bands".
- p. 8 Section 3, last paragraph (top of page)
most of the models listed in Table 1 produce differential transits
- p. 15 Table 1 and Table 2 captions
Table 2. Model Atmosphere Parameters
- p. 7 Section 3, third paragraph
These variants are listed in Table 2.
- p. 15 Table 2 title
Model Atmosphere Parameters
Judge's note: Opened p8 (the sentence), p15 (both tables) and p7. Table 1 holds only the nine band ranges; Table 2 lists s1, n1-n4, c1-c3, including n4 and c3 named in the next sentence. Section 3 itself says on p7 'These variants are listed in Table 2'. The pointer should read Table 2.
Second check: another model agreed
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Reference or label Figure 7: the x-axis tick labels run 0.0, 0.02, 0.04, 0.06, 0.08, "1.10", "1.12"; the last two should read 0.10 and 0.12 days.
- p. 24 Figure 7, x-axis tick labels
1.10
- p. 24 Figure 7, x-axis tick labels
1.12
- p. 17 Figure 2, x-axis (same axis, correct labels)
0.10
- p. 24 Fig. 7, x-axis tick labels
1.10 1.12
Judge's note: Seen on the p24 page image itself (this page's text is OCR, so the image was the check): the labels are printed '1.10' and '1.12' at evenly spaced ticks after 0.08, with no axis break. Figure 2 on p17 has the same axis, with the same contact lines near 0.046 and 0.064 days, labelled 0.10 and 0.12.
Second check: another model agreed
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9 minor (typos and the like; most checked by the judge only)
Wording Abstract: "Our model for a cloudless planetary atmosphere with a solar abundance of sodium in atomic form predicts more sodium absorption than we observe", but the model compared with the data is the fiducial model s1, which "has a cloud deck with cloud tops at a pressure of .0368 ( = 0.1 / e) bar" (Section 3; "cloud tops at 0.04 bar" in Section 4.2), and no model in Table 2 is cloudless.
- p. 1 Abstract
Our model for a cloudless planetary atmosphere with a solar abundance of sodium in atomic form predicts more sodium absorption than we observe.
- p. 7 Section 3, third paragraph
The fiducial model has a cloud deck with cloud tops at a pressure of .0368 ( = 0.1 / e) bar
- p. 9 Section 4.2, first paragraph
Our fiducial model (s1), which has cloud tops at 0.04 bar and a solar abundance of sodium in atomic form
- p. 9 Section 4.2, first sentence
Our fiducial model (s1), which has cloud tops at 0.04 bar and a solar abundance of sodium in atomic form, predicts values
Only the authors can say what is right here.
Judge's note: Read the abstract (p1), Section 3 (p7), Section 4.2 (p9) and Table 2 (p15) on the page images. Every model in Table 2 has a cloud deck; the deepest is n1 at 3.68 bar. The captions of Figures 6 and 7 say models n1 and n2 (deeper clouds) are indistinguishable from s1, so 'cloudless' may be meant as 'effectively cloud-free in this band', but the paper never says so. A wording mismatch between abstract and body; the numbers are not affected.
Second check: another model agreed
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Wording Equation (2) prints errors "(−2.0 ± 2.5) × 10−5", "(+0.1 ± 2.7) × 10−5", "(−3.1 ± 4.1) × 10−5" beside scatters "σ[nd(tout)] = 3.3 × 10−4, σ[md(tout)] = 3.6 × 10−4, and σ[wd(tout)] = 5.4 × 10−4"; with 171 in-transit and 207 out-of-transit points these scatters give 3.4, 3.7 and 5.6 × 10−5 for a difference of two means, whereas the same calculation reproduces the equation (5) errors (5.7, 3.8, 3.6) exactly.
- p. 4 Equation (2)
(−2.0 ± 2.5) × 10−5
- p. 4 Section 2.1, after equation (1)
σ[nd(tout)] = 3.3 × 10−4, σ[md(tout)] = 3.6 × 10−4, and σ[wd(tout)] = 5.4 × 10−4
- p. 6 Equation (5)
(−23.2 ± 5.7) × 10−5
Only the authors can say what is right here.
Judge's note: Read equations (2) and (5) and the scatters on the p4 and p6 images. Expressions below are in units of 1e-5 and squared, because the checker has no square root: the squared error of a difference of means is sigma^2*(1/171+1/207). Equation (5): 32.3, 14.6, 13.1 against printed squares 32.5, 14.4, 13.0, a match. Equation (2): 11.6, 13.8, 31.1 against printed squares 6.25, 7.29, 16.81, no match. The equation (2) errors equal sigma^2/171, the error of the in-transit mean alone (6.37, 7.58, 17.05). The paper calls both sets the standard deviation of the mean ('As before' on p6) and does not give a separate in-transit scatter for the difference series, so the two equations appear to use different error formulas. The 'consistent with no variation' reading holds either way. Authors to say how the equation (2) errors were computed.
Second check: another model agreed
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Typo Figure 5 caption: "The lower panel shows the corresponding results for the middle (m) band pass"; the band is defined as "medium" (m) in Section 2 and Table 1.
- p. 22 Figure 5 caption
The lower panel shows the corresponding results for the middle (m) band pass.
- p. 3 Section 2, fifth paragraph
“narrow” (n), “medium” (m), and “wide” (w)
- p. 22 Fig. 5 caption
results for the middle (m) band pass
- p. 3 Section 2
“medium” (m)
Judge's note: Caption read on the p22 image; definition on the p3 image ('“narrow” (n), “medium” (m), and “wide” (w)') and Table 1 on p15 ('medium'). The same caption also uses 'middle' for the middle panel, which shows the narrow band. The '(m)' makes the meaning recoverable.
Second check: none (judge only)
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Typo Section 2.1: the paragraph ends "and at 17 values of µ ∈ [0, 1]" with no full stop.
- p. 4 Section 2.1, paragraph before 'The stellar model allows us'
and at 17 values of µ ∈[0, 1]
Judge's note: Checked on the p4 page image: the line ends at '[0, 1]' with no period, and a new paragraph follows. Not an extraction loss.
Second check: none (judge only)
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Typo The stellar effective temperature is written "Teff = 6000 K" in Section 2.1 and "stellar effective temperature (Ts = 6000 K)" in Section 3.
- p. 7 Section 3
stellar effective temperature (Ts = 6000 K)
- p. 4 Section 2.1
Teff = 6000 K
Judge's note: Both forms seen on the p4 and p7 images; same value, same source (Mazeh et al. 2000). 'Ts' follows the paper's own subscript convention for stellar quantities (Rs, Ms), and 'Teff' is later used for the planet's equilibrium temperature on p8, so either symbol is defensible. A notation inconsistency only.
Second check: none (judge only)
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Typo Section 4.2: "(K. Lodders, personal communcation)" should read "communication".
- p. 9 Section 4.2, second paragraph
(K. Lodders, personal communcation)
- p. 9 Section 4.2, first paragraph
K. Lodders, personal communcation
Judge's note: Seen on the p9 page image: 'communcation', missing an 'i'. The same page prints 'E. H. Avrett, personal communication' correctly.
Second check: none (judge only)
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Typo Section 4.2: "Perhaps HD 209458 began with a depleted sodium abundance"; the context is the planet's primordial abundance (the star is stated to have solar metallicity), so "HD 209458 b" appears to be meant.
- p. 10 Section 4.2, first line of page
Perhaps HD 209458 began with a depleted sodium abundance
- p. 10 Section 4.2, same paragraph
planets should present a metallicity at or above the value observed in the parent star
Judge's note: Read on the p10 image. The next sentence contrasts planets with their parent star, and p7 gives solar metallicity as 'the measured value for HD 209458', so the sentence is about the planet. But the paper uses the bare star name for the planet or system elsewhere too ('transmission spectrum of HD 209458' on p8 and in the Figure 8 caption), so this is loose naming and not a clear slip.
Second check: none (judge only)
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Typo Reference list, Coustenis et al. 1998: "ed. R. Rebolo, E. Matín, & M. R. Zapatero Osorio"; the editor's surname appears to be missing an 'r' (Martín).
- p. 12 Reference list, Coustenis et al. 1998
Rebolo, E. Matín, & M. R. Zapatero Osorio
Only the authors can say what is right here.
Judge's note: Rests on outside knowledge: that the second editor of ASP Conf. Ser. 134 (Brown Dwarfs and Extrasolar Planets) is E. L. Martín. This cannot be checked from the files. The p12 page image does print 'Matín', so the odd spelling is in the paper and is not a text-layer artefact.
Second check: none (judge only)
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Typo Reference list is out of alphabetical order: "Collier Cameron, A., ..." and "Cox, A. N. 2000, Allen’s Astrophysical Quantities" are printed before the three Charbonneau entries ("Charbonneau, D., Brown, T. M., Latham, D. W. & Mayor, M. 2000, ApJ, 529, L45" etc.), which are followed by Coustenis.
- p. 12 Reference list
Cox, A. N. 2000, Allen’s Astrophysical Quantities
- p. 12 Reference list
Charbonneau, D., Brown, T. M., Latham, D. W. & Mayor, M. 2000, ApJ, 529, L45
- p. 12 Reference list
Cox, A. N. 2000, Allen’s Astrophysical Quantities, 4th ed., ed. A. N. Cox, (New York: AIP Press)
Judge's note: Checked the order on the p12 image: Butler, Collier Cameron, Cox, Charbonneau (three entries), Coustenis, Deeg. The rest of the list is alphabetical. Cosmetic; no entry is missing.
Second check: none (judge only)