Investigation of the Nature of the B[e] Star CI Cam in the Optical Range

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This manuscript presents an impressive 25 year monitoring of the optical variations of the CI Cam system. I am in favor of the publication of this work after some adjustments that should enhance its readability. 

1. The introduction is long and present results already published in the most part in Barsukova et al., AstBu (2023), where the same work is described in much more details. Figures 1, 2, 4, 5 and 6 are almost identical to those of the 2023 paper. A briefer recap of previous work would bring more attention to the updates this work provides.
2. The conclusion that the secondary star is a stripped or naked star is quite interesting. It is unclear, though, how this conclusion was reached. The manuscript mentions the star's position in the HR diagram, but there are only discussions on its luminosity, not its temperature. More details on this conclusion would be informative.
3. Some of the citations are made using the wrong numbering (e.g., [10] instead of [8] and [9] instead of [10].
4. It is surprising that there are no reference to the work of Klochkova, Miroshnichenko and Panchuk (2024) on the spectroscopic monitoring of CI Cam. 

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The paper of Barsukova et al presents long-term observations for CI Cam, a really unique B[e] object. Studies of this depth are needed in order for us to understand these objects and how they evolve, with CI Cam being such a case with a dramatic change in its appearance challenging many scenarios. 

As I was digging into the paper I did not find the description of the observations and the method very thorough, so I looked into the first reference provided by the authors [1] (Barsukova et al. 2023, AstBu, 78, 1, "Investigation of the Nature of the B[e] Star CI Cam in the Optical Range", https://ui.adsabs.harvard.edu/abs/2023AstBu..78....1B/abstract). When I started reading that paper which is entitled "Investigation of the Nature of the B[e] Star CI Cam in the Optical Range" (the exact same as the submitted work), I noticed that most of the text and figures that is presented in the work submitted in Galaxies is similar (if not the same) with that paper. E.g. Fig 1 of the current paper is just a cut from Fig 1 in Barsukova+2023, Fig 5 of the current paper is the same with Fig 2 in Barsukova are the same (and similarly for almost all figures). 

The possible difference (if present) between the two works could be the numbers of years considered, i.e. 25 years (current work) vs. 24 years (previous one). But this is not enough to justify another paper with the same exact images and text. I would suggest the authors to explore other alternatives, such as to investigate more the variability of other lines and compare / include more photometric light curves.

Given the lack of scientific advancement and plagiarism, I regret to inform you that the current paper cannot be accepted for publication.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This paper focuses on CI Cam, a peculiar and extensively studied object whose nature has been controversial for many years. Nowadays, it is widely considered a binary (or triple?) system that displays the B[e] phenomenon and the optical counterpart of the X-ray source XTE J0421+560. The manuscript presents a study of new spectra taken around the He II 4686 A line when the secondary binary component was at the descending node of the orbit. The monitoring covers a time interval similar to the pulsation period of the primary component. The authors analyse the behaviour of the equivalent widths (EWs) of the He II emission line in function of time and propose an explanation for the observed variations.

New data is always valuable, particularly for objects associated with peculiar phenomena, and could help constrain the nature and evolutionary stage of the binary system components. However, the new research and findings need to be emphasised. In the Abstract, the authors state that they are reporting the results of 25 years of photometric and spectroscopic monitoring of CI Cam. These results are carefully described in the Introduction section, which contains figures that have already been published in different works by the authors (and are cited here ). Of a total of 7 pages, more than half are devoted to background. I think the current paper would benefit more if the authors made some modifications. For example, it would be valuable to include a description of the method used to obtain the observables and to extend the discussion of the results.   

Given the above, I recommend the paper for publication after major revisions.

Detailed comments:

Abstract:
It should be adapted to highlight the new research, its goal and results. 

Introduction:
I suggest leaving only the figures that are new or necessary for presenting the novel results (such as Figures 1 and 4) and, if corresponding, highlighting the new data in the plots using colour or different symbols. The authors could reference the rest of the figures in the text according to their original publication.
In addition, I recommend including in this section a paragraph about previous classifications of CI Cam by other authors and contextualizing this object within the B[e] phenomenon.

Fig. 1:
The label of the x-axis should be changed to JD-2400000. The first tick label should be changed to 51000.

Fig. 3:
The caption should be modified since "phased with the period of 19.41 day" does not make sense. Also, a blanck is missing between 4686 and the symbol angstroms, which is not correctly written. It would be helpful to add the orbital period phase corresponding to the acquisition of each spectrum.

Fig. 4:
It would be useful to highlight in colour (or with a different symbol) the EW and radial velocity values of the He II emission line derived from the new spectra.

Last paragraph - first sentence:
Regarding the statement "CI Cam is currently the only known B[e] star in which pulsations have been observed", it should be noted that in HD 50138, Krtickova & Krticka (2018) detected pulsations. 

Last paragraph - last sentence:
The reference seems to be wrong. Do the authors mean: [1]?

Observations:
It would be useful to add some information about the observations (like exposure times, S/N ratio, spectral range) and the reduction process. It should be specified what kind of procedures were followed to obtain the radial velocities and EWs of the He II line (and their uncertainties), since the line profile changes considerably throughout the monitoring. It should be mentioned if the methodology applied to the Fe lines was the same. 

Results:
This section should be improved to be convincing. It would be worth highlighting what is new in the results found in this work. The interpretation of the behaviour of the He II line EWs as a function of time given in the last sentence requires further elaboration. How does it follow from this variation that the structure of the radiation source must be extended? Could the authors give a joint interpretation of the behaviour of the He II line EWs according to both the pulsation period and the orbital one? A schematic description of the system may help visualize the proposed scenario. Could the authors make a comment about the presence of the third body proposed in the literature?

Second sentence:
"In Figure 4a, this phase is marked by the large vertical arrow." It could be changed to: In Figure 4a, the phase of the observations is marked...

Third sentence:
"Two maxima in equivalent width were observed, with values varying by more than a factor of three...". Do the authors mean that the maxima have changed their values by more than a factor of three? If not, it should be modified.

Fourth sentence:
Are the values in parentheses an average of the measured equivalent widths of the iron lines?  

Fig. 8:
The values of the EWs in this figure are considered negative. However, in Figure 4c they are positive. It would be convenient to use the same convention in both cases. The label of the x-axis should be changed to JD-2460249. The first tick label should be changed to 0.10.
Concerning the caption, it says: "a change in the EW of the helium emission line three times during the observation period..." Do the authors mean: a change in the EW of the helium emission line by a factor of three...? In addition, "almost equal to the orbital period" should be changed to: almost equal to the pulsational period.

Discussion:
This section could be improved. It would be valuable to discuss the evolutionary path followed by the binary system to reach the current proposed stage (B0-2 III + Of subdwarf).

Last sentence:

The reference is wrong. It should be [10].

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

This article presents some new high-resolution spectroscopic observations of CI Cam, a peculiar and intriguing system exhibiting the B[e] phenomenon. These observations could provide evidence to discuss the object's nature, which is still under debate. The subject of article is scientifically relevant; however, I recommend publication only after major revisions. The main reason for this recommendation is that most of the content of the manuscript refers to data and results that have already been extensively presented in a recently published article: Barsukova et al. 2023, Astrophysical Bulletin, Volume 78, Issue 1, p.1-24. (I have read the openly accessile preprint version but I have no access to the final Springer version), and to which the authors of this article make reference. Moreover, the new results presented in this article are limited and briefly explained and discussed.

Major issues

-Title: Investigation of the Nature of the B[e] Star CI Cam in the Optical Range

-The words "Optical Range" are too general and does not represent the main results shown in the article. Although many optical data is presented it is not part of the actual investigation of the paper, just background information. The new results in the  article focused particularly on the He II 4686A emission line.  

-Abstract

The text of the abstract is misleading.

The beginning of the abstract says: "We report the results of 25 years of ..."which gives the impression that the article will be a review or a detailed description for 25 years of observations of the object under study. However, "the results from 24 years of photometric and spectroscopic monitoring of CI Cam" were already thoroughly reported and discussed in Barsukova et al. (2023). 

I suggest to rewrite the abstract, particularly highlighting the results of the present article which, as I understantd, are the presentation of new high resolution spectroscopic observations of the He II 4686A emission  line variability and its interpretation. 

-Introduction

The article consists of 7 pages, of which 4 are dedicated to presenting data and results about the object of study, most of which were previously published. The results, discussion and conclusion are presented in 2 pages, while the seventh contains references and acknowledgments.

The Introduction section is unnecessarily long and should be shortened to no more than two pages. It should provide a concise summary of the object's characteristics and phenomenology to date, emphasizing previous data or results that are directly relevant to the findings of the current article.

Most of the figures presented in the Introduction have already been published almost identically in the previous mentioned article. There is no need to show all of them here again, it is sufficient to cite them. Only figures 4 and 6, although already published, may be worth to be shown, as they have a direct connection to the subsequent results and discussion.
The following figures should be removed.
-Figure 1 is similar to Figure 1 from Barsukova et al. (2023) (Preprint), except that it added some more points to the light curve.
-Figure 2, 5 and 6 are similar to figure 6, 2 and 8, respectively, from Barsukova et al. 2023 (Preprint).
-Figure 3 shows the shift of He II emission line at two different epochs, a result that can be directly inferred from the radial velocity curve shown in fig. 4. (Preprint)

-Results 
The result shown in this section is the variability of the EW of  the He II emission line 4686A with the pulsation period of 0.40 days.

The only sentence that comment on this result is: "We believe that we have observed the interaction between the radiation source and the two pulsation waves, with the total interaction surface directed toward the observer and the radiation source exhibiting an extended structure."

A very similar comment was written in Barsukova et al. (2023): "The dependence of the He II 4686 Å line equivalent width (EW) on the orbital phase is shown in Fig. 6c. The largest emission EW is observed near the descending node of the orbit.[...]Barsukova et al. (2021) explain the peak emission in this phase as resulting from the interaction between the emission source and the pulsation wave, where the total interaction surface is directed toward the observer, and the emission source has an extended structure."

The authors should highlight the original contribution of the new observations presented in this article, or what this observations add to the previous ones presented in Barsukova et al. (2023).

Considering the large scattering in the He II line EW values (figure 4 (c)), a reliable conclusion on the EW variability with the pulsation period, requires repeating the same set of observations during the descending node and at other orbital phases. Just one set of observation provides insufficient evidence to confirm that the variability is linked to the pulsation and it is not a random result.

-Discussion
The Discussion section should be more extended and detailed. It does not give enough background information to describe the proposed scenario and confront it with other hypothesis.

The hypothesis of an Of-type component was already suggested in  Barsukova et al. (2023):
"It may turn out to be a hot Of-type subdwarf, whose spectrum cannot be distinguished from the B star's emission in the total spectrum."

Again, the authors should highlight how the results presented in this article are important to decide on the nature of the system and relevant enough to justify a new publicacion.  

-Conclusions
The FS CMa group is only mentioned in the conclusions, a brief description of the characteristic of this group should be added. 

The conclusions written in this section are  similar to that of Barsukova et al. (2023), in which at the end of this article abstract says:  "CI Cam is likely a system in the post-first mass exchange stage and may belong to the FS CMa-type group of objects exhibiting the B[e] phenomenon." and the last paragraph says:  "It is likely that CI Cam is a system that has undergone its first mass transfer and can be identified as a FS CMa-type B[e] star.

In the Conclusion section, the authors should resume the investigation presented in this article, instead of express what it was already concluded in their previous article.

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Minor corrections:

-Results:

In Fig. 8 I believe the caption should say  "The upper panel: a change in the EW of the helium emission line three times during the observation period, almost equal to the PULSATION period."  instead of "ORBITAL period."

In Fig. 8 EW are expressed as negative values, while in Fig. 4c are positive values. 

-Discussion:
In the last sentence the citation should be [10] instead of [9]

 

 

 

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The updated paper of Barsukova et al presents new spectroscopic observations from 2023 for CI Cam (an important B[e] object) as part of the long-term monitoring. I truly believe that this kind of monitoring is paramount for our understanding of this, and other, weird objects.

Although the authors tried to change and shorten their paper regarding the context, I find that they put too much effort in trying to publish the results of a single night. Again by cross-checking with their work (Barsukova et al. 2023, AstBu, 78, 1, "Investigation of the Nature of the B[e] Star CI Cam in the Optical Range", https://ui.adsabs.harvard.edu/abs/2023AstBu..78....1B/abstract), this radial velocity variation of about 200 km/s for He II line 4686 is not observed for the first time. 

I find that the additional information, i.e. the addition of a single night of multiple spectroscopic observations, does not contribute to the overall science advance. The data are limited as well as the interpretation. The idea of the interaction between the radiation source of the HeII line and the pulsation waves (along with the direction alignment to the observer) is also mentioned in the first work of Barsukova et al. 2024 and perhaps even earlier (as written in Barsukova et al. 2024, "Barsukova et al. (2021) explain the peak emission in this phase as resulting from the interaction between the emission source and the pulsation wave, where the total interaction surface is directed toward the observer, and the emission source has an extended structure. As the source enters the denser layers of the pulsating B star's envelope, it attains a relative velocity of more than 200 km/s with respect to the surrounding medium.").

Moreover, the manuscript itself is not of sufficient level to get published. Indicative issues:

- Introduction does not read as such. It starts describing results. In paragraph 1, last sentence, there is a series of spectral types but there are no references to the papers. Also CI Cam has a series of changes in its companion which is worth mentioning in the introduction. Moreover, it lacks of a quick description of what B[e] stars and their properties.

- Results/Discussion are very limited, with a lot of information written but without enough justification (e.g. missing references, explanation of the phenomena). 

- In conclusions, at the very last sentence a reference to FS CMa-type stars is done but without any citation and description of that they are. 

- The figures are not significantly different that their previous paper. 

- The authors are missing a lot of references to other works in the field. 

Given the lack of scientific quality, I regret to inform you that the current paper cannot be accepted for publication. 

I urge the authors to not be hasty. They are doing a great job with the monitoring of such an object, and I would suggest them to first collect enough more data and perform a comparison with previously published results (something that I missed in this version, such as comparing the HeII profile from this single epoch with previous ones). 

 

Author Response

Please see attached file.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Dear Authors,

I appreciate that the suggestions made have been taken into account and many of the proposed changes have been made. I believe this version of the article highlights the new results much more than the previous version. I only have a few minor corrections:

1) Introduction: 3rd paragraph - 1st sentence: "...the magnitude of these shifts depending on the photometric phase...". It should be changed to "...the magnitude of these shifts depends on the photometric phase..."

2) Observations: 2nd paragraph: "The exposures were 3600 seconds each." I suggest adding the word "averaged" because, considering the UT differences in Figure 3, it's clear that at least one of the exposures were shorter: "The exposures averaged 3,600 seconds each."

3) "...(the average EW = 0.28 Å ) and ... (the average EW = 0.89 Å )." Following the convention of EW, they should be negative values.

Kind regards

Author Response

Dear reviewer,

Thank you for the great and important work you have done for us. We have made adjustments to all your comments in the revised version. Thank you very much again for your comments! We hope that now our article will be read easier and with even more interest.

Best wishes!

Grateful authors

Reviewer 4 Report

Comments and Suggestions for Authors

The authors have revised the text in accordance with all my suggestions, and therefore, I believe it is suitable for publication in its revised version.

Author Response

Thank you very much for taking the time to review our manuscript.

Once again, we sincerely thank the referee and hope that our article is now more interesting.

Sincerely yours,

Grateful authors

Round 3

Reviewer 2 Report

Comments and Suggestions for Authors

The updated manuscript by Barsukova et al. now focuses on new results from a concentrated spectroscopic campaign during a single night, aiming to probe the variability of the He II 4686 line in CI Cam. The authors attribute this variability to a newly proposed interaction mechanism (“raking accretion”) as the secondary moves through the primary’s wind. Based on the energetics and line variability, they suggest that the companion is not a white dwarf but a stripped hot subdwarf, likely the product of prior mass exchange.

This is indeed an intriguing scenario, coming from an original observing campaign, that contributes meaningfully to our understanding of B[e] binaries and stripped stars. Therefore, I can suggest publication, but only after addressing the following two major points, along with a number of minor ones detailed below.

A. The authors need to clarify several parts of the manuscript where intriguing ideas are introduced but not yet clearly defined or supported (e.g., the "raking" mechanism). In particular, stronger evidence is needed to support the hypothesis that the companion is a hot subdwarf rather than a white dwarf of a main-sequence star (as is the case with FS CMa class), both conceptually and observationaly. Therefore, I strongly suggest them to revisit their text by having in mind how to clearly present and support their results. 

B. The authors also need to work on the structure of the paper. In particular, they need to split better the text among the various sections (introduction, results, discussion). The majority of the information is there so it is mainly rearranging text. 

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Minor points (in the following 'p' corresponds to paragraph)

- introduction:
-- 1p, "The classification of CI Cam has changed multiple times since its study began in 1932 [2]. Then the spectrum of the star was obtained" < the initial spectral type (types) is (are) missing for the reader to have an idea of the changes (especially since "then" is used in the second sentence). 
-- p1, Please provide the references to the papers when referring to specific classifications (e.g BoV+G8II; Athors year), ... Recent consensus seems to a supergiant (Authos1 year, author2 year, etc). 
-- p1, A number of references is given from various observations but not real information regarding what we learn. Please update this part with some key points from each of these works. This is the place to add any work regarding the mechanisms of interaction between the companion and the B stars. 
-- p2, the figure is very similar to previous one published. Since the authors want to include this I would suggest them to highlight (with another color) the new (additional) observations that show the increase in the brightness. 
-- p3, "clearly is visible" < remove "is" 
-- p3, "On nights when this emission is not visible in spectra with exposure times of, for example, 40 minutes, it becomes detectable when the total exposure time is increased to four hours." This sentence claims that the detection of the line is sensitive to the SNR, so provide numbers with respect to that and not exposure times (which are difference from one facility to the other). I suppose that the HeII line should have been present in almost all good quality spectra *if* it was there at all times (which is the author's argument regarding the variability). 
-- p4, "The full amplitude of radial velocity variations exceeds 500 km s-1." In Fig 2 I see max at 100 km/s and min -300 km/s, so 400 km/s in total. How does 500 km/s comes up as a number?
-- p5, "Initially, three pulsation modes were present. Since 2012, the star has pulsated in a single mode [13] with a period of 0.4062 days" what kind of modes? 
Perhaps a reference to a review paper on pulsations is useful here (eg Saio+2013 https://ui.adsabs.harvard.edu/abs/2013MNRAS.433.1246S/abstract or similar). 
-- p5, end of paragraph, perhaps a few papers regarding TESS data and blue supergiants can be added (such as Bowman 2024, https://ui.adsabs.harvard.edu/abs/2023Ap%26SS.368..107B/abstract, Kourniotis+ 2025, https://ui.adsabs.harvard.edu/abs/2025arXiv250320860K/abstract)
-- Please split the introduction to a general introductory text regarding CI Cam and its importance, and highlight the potential of this work to contribute new insights. Refer to previous knowledge and papers (including the Figures 1 and 2) as another section (eg background information, previous works, or even under results) - so that to separate the introduction to the presentation of previous own and current results (such as the reference in introduction in p4: "is presented in Figure 2a of this paper").  

Fig 2: 
-- there are two sets of orange points, possible due to the duplication of the folding - please fix it to present points once
-- "smoothed He II radial velocity curve." < how was this smoothening performed?
-- "using graphically determined orbital elements;" < how were those determined? if they come from another paper please add the citation here.

- observations
-- p3, "the slicer spectra from both circular polarizations were combined and processed using the MIDAS package" this was done to increase the SNR as due to the spectropolarimetric mode the light splits into two modes. If that is the case please write it more explicit for any reader to understand if and how the circular polarizers were used.
-- p3, SNR per pixel is ok but it is better to provide a single SNR number per spectrum (either in the text or the figure). This should be proportional to the number of pixels that resolve the HeII line.
-- p3, "about seven million kilometers along its orbit." this depends on the distance assumption. Either state the distance used or add some error. However, how important is this number? 

- results
-- p1, how is the redial velocity calculated?based on which line?
-- p1, how was the EW measured? 
-- p2, "We are confident" what are the arguments that support this confidence? The authors mention a plausible mechanism that the HeII EW variability is driven by the modulations from the pulsations of the B[e] stars (which is interesting), but without any quantitative models or direct measurements from observations. I strongly suggest rewording this statement to reflect that it is a working hypothesis rather an established fact. 
-- p3, this paragraph is the main idea of the whole project, but its logic is difficult to follow. It would benefit from restructuring to more clearly separate (1) what was previously known or proposed, (2) the hypothesis that led to new observations, and (3) the reasoning about cross-sectional area and interaction strength. I strongly suggest to revisit this paragraph to improve clarity, precision, and logical flow, which will strengthen the manuscript substantially.
-- p4, "we found that this night the periodicity of interaction with the shock waves was half the pulsation period." Although reasonable , I am thinking that this may be biased because of the observation time span. The observing window was 9.8 hours very close to the pulsation period of 9.84 hours. The observation of two maxima within a single cycle could, in principle, could also arise from windowing effects or more complex (non-sinusoidal) pulsation modulations. To firmly establish the existence of a stable half-periodic interaction, monitoring over multiple pulsation cycles would be highly desirable. I recommend that the authors either acknowledge this limitation in their discussion and suggest targeted follow-up observations (over longer time baselines) to distinguish between stable half-period modulation and windowing or aliasing artifacts.
-- p5, This is an interesting interpretation for the HeII variability. But I have to stress that this event can also occur in hot spots of white dwarfs (eg cataclysmic variables). It should be emphasized that it is the combination of the emission variability and strength, the lack of accretion disk signatures, and the total bolometric energy budget that (all together) point away from a white dwarf.
-- p6, The idea of the "raking accretion" is interested, but this section needs elaboration. The description is too brief without a clear definition. I suggest the authors explain in more detail the physics behind this (as much as this is possible) and how it compares with other accretion mechanisms. Moreover, they need to explain how the observational properties relate with the mechanism.
-- p7, The idea that the observed bolometric luminosity increase during periastron rules out a white dwarf companion is convincing. I would suggest that the discussion could be further strengthened by explicitly noting that the inferred mass of the secondary (0.98–1.77 M☉) falls comfortably within the expected range for stripped hot subdwarfs, according to recent observational and theoretical studies. This would reinforce the plausibility of the proposed companion classification.
-- p8, last. This is a closing paragraph that gives the opportunity to the authors to provide a wrap up of their findings and perhaps a future plan on how to verify and make more robust their conclusions. Currently it reads somewhat vague and nonspecific (eg numerous questions but only a couple are named). Please revisit it and try to highlight more specific goals and concrete methods.  
-- Except for the first paragraph of results, the majority of the text in this Section seems more appropriate for the Discussion. 

Fig 3: Relative intensity means that the spectra were normalized. Please clearly state this in the figure or in the text. 
There are additional important information missing such as SNR, and phase. The authors should consider perhaps to add a table with a log of the observations, instead of populating a figure with all these information (such as SNR, phase, time of observation)

- discussion
-- p1, How is the calculation of the bolometric luminosity (of 1800 Lo) is performed? Please provide some more details.
-- p2, "Our spectroscopic observations show no evidence of a double-peaked He II 4686 Å emission profile, indicating that the secondary does not host an accretion disk." I understand that the geometry is not pole-on, so the single-peaked scenario for the HeII line is rejected (possibly something that the authors could add in their text). However, the spectral resolution of the instrument is paramount to get the broadening. Are their any calculations that can safely exclude this scenario ?
-- p2, "compact companion" since the conclusion is a hot subdwarf then this terminology is inconsistent with "compact" (referring to white dwarfs, neutron stars, black holes. Remove "compact" in this case, and use another term (companion, the secondary). 
-- p2, The authors say that the interaction coincides with the pulsations waves, leading to this observed HeII variability profile. is it possible to explain how this is happening?What could be the result if this didn't happen?
-- p3, Considering the relative velocity of ~200 km s-1, and the recurrence of interaction every 19.407 days, the formation of a stable accretion disk is unlikely." Please elaborate why this is unlikely. 
-- p3, How different is the "raking" mechanism to the thermonuclear outburst in white dwarfs? Because the last ones occur in cases where degenerate sources are present, but not in the non-degenerate hot subdwarf. The authors should clearly explain the differences and how this is distinguished from the white dwarf mechanism.   

- conclusions
-- p2-3.  The authors link CI Cam to the FS CMa class of B[e] stars, emphasizing its post-mass exchange nature and binary evolution. While CI Cam does share some observational features with FS CMa stars the proposed nature of the secondary (a stripped hot subdwarf) is at odds with the usual FS CMa model, where the companion is typically a main-sequence or slightly evolved star. I suggest the authors clarify this potential inconsistency: either by acknowledging that CI Cam may represent a more evolved or atypical case within the FS CMa population, or by discussing whether the presence of a stripped subdwarf still fits within the broader evolutionary framework of this class.
-- A big part of the conclusions, especially the discussion about the FS CMa stars, is again appropriate for the discussion. 
Please rearrange the text to better reflect this structure and the content of the work (it is possible to split the discussion in two parts, on the nature of CI Cam and its link to FS CMa stars). During the rewriting of the discussion present collectively the arguments that support the hypothesis of the hot-subdwarf nature of the secondary in CI Cam.

- additional suggestions
-- It would help if the authors included a table summarizing the key orbital and pulsational parameters (e.g. orbital and pulsational periods, eccentricity, phase coverage of the observation, exposure times). This would centralize important numbers for the reader.
-- It would be beneficial to the community if the authors could outline, even briefly, a roadmap for how similar observational campaigns could be designed for other systems or help identify stripped subdwarfs. This can make their methodology more accessible to future observers.
-- The current title ("Investigation of the Nature of the B[e] Star CI Cam in the Optical Range") is rather broad and descriptive. I suggest that the authors consider a more focused title that reflects the novel aspects of the work (eg the identification of a stripped hot subdwarf companion, the He II line variability, or the proposed "raking accretion" mechanism). A more specific title would better convey the manuscript’s contribution to readers and improve its visibility.

Author Response

See attached file.

Author Response File: Author Response.pdf