New spectroscopic classifications of 35 chemically peculiar candidate stars

Paunzen, E.; Netopil, M.; Pintado, O. I.; Rode-Paunzen, M.

doi:10.1002/asna.201011477

Cited by 11 publications

(14 citation statements)

References 34 publications

(35 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Because at least classification resolution spectroscopy is necessary to establish the true nature of a peculiar object (e.g. Paunzen et al 2011), we used the relevant extensive catalogue by Skiff (2010) to verify all spectral types. If contradicting classifications were found, a question mark was set.…”

Section: Resultsmentioning

confidence: 99%

A photometric study of chemically peculiar stars with the STEREO satellites - I. Magnetic chemically peculiar stars★

Wraight¹,

Fossati²,

Netopil³

et al. 2011

Monthly Notices of the Royal Astronomical Society

Self Cite

View full text Add to dashboard Cite

About 10 per cent of upper main‐sequence stars are characterized by the presence of chemical peculiarities, often found together with a structured magnetic field. The atmospheres of most of those chemically peculiar stars present surface spots, leading to photometric variability caused by rotational modulation. The study of the light curves of those stars therefore permits a precise measurement of their rotational period, which is important to study stellar evolution and to plan further detailed observations. We analysed the light curves of 1028 chemically peculiar stars obtained with the STEREO spacecraft. We present here the results obtained for the 337 magnetic chemically peculiar stars in our sample. Thanks to the cadence and stability of the photometry, STEREO data are perfectly suitable to study variability signals with a periodicity typical of magnetic chemically peculiar stars. Using a matched filter algorithm and then two different period searching algorithms, we compiled a list of 82 magnetic chemically peculiar stars for which we measured a reliable rotational period; for 48 of them, this is the first measurement of their rotational period. The remaining 255 stars are likely to be constant, although we cannot exclude the presence of long‐period variability. In some cases, the presence of blending or systematic effects prevented us from detecting any reliable variability and in those cases we classified the star as constant. For each star we classified as variable, we determined temperature, luminosity, mass and fractional age, but the limited statistics, biased towards the shorter periods, prevented us from finding any evolutionary trend of the rotational period. For a few stars, the comparison between their projected rotational velocity and equatorial velocity let us believe that their real rotational period might be longer than that found here and previously obtained. For the 82 stars identified as variable, we give all necessary information needed to plan further phase‐dependent observations.

show abstract

Section: Resultsmentioning

confidence: 99%

A photometric study of chemically peculiar stars with the STEREO satellites - I. Magnetic chemically peculiar stars★

Wraight¹,

Fossati²,

Netopil³

et al. 2011

Monthly Notices of the Royal Astronomical Society

Self Cite

View full text Add to dashboard Cite

show abstract

“…About 45 000 spectra were discarded in this manner. This cut was imposed because the detection of CP star features in objects with S/N < 50 is difficult (Paunzen et al 2011). In the case of objects having more than one spectrum in the DR4 catalogue, we considered only the spectrum with the highest Sloan g band S/N.…”

Section: Sample Selection Processmentioning

confidence: 99%

New mercury-manganese stars and candidates from LAMOST DR4

Paunzen

Hümmerich

Bernhard

2021

A&A

Self Cite

View full text Add to dashboard Cite

Aims. The present work presents our efforts at identifying new mercury-manganese (HgMn/CP3) stars using spectra obtained with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). Methods. Suitable candidates were searched for among pre-selected early-type spectra from LAMOST DR4 using a modified version of the MKCLASS code that probes several Hg ii and Mn ii features. The spectra of the resulting 332 candidates were visually inspected. Using parallax data and photometry from Gaia DR2, we investigated magnitudes, distances from the Sun, and the evolutionary status of our sample stars. We also searched for variable stars using diverse photometric survey sources. Results. We present 99 bona fide CP3 stars, 19 good CP3 star candidates, and seven candidates. Our sample consists of mostly new discoveries and contains, on average, the faintest CP3 stars known (peak distribution 9.5 ≤ G ≤ 13.5 mag). All stars are contained within the narrow spectral temperature-type range from B6 to B9.5, in excellent agreement with the expectations and the derived mass estimates (2.4 ≤ M ⊙ ≤ 4 for most objects). Our sample stars are between 100 Myr and 500 Myr old and cover the whole age range from zero-age to terminal-age main sequence. They are almost homogeneously distributed at fractional ages on the main sequence ≤ 80 %, with an apparent accumulation of objects between fractional ages of 50 % to 80 %. We find a significant impact of binarity on the mass and age estimates. Eight photometric variables were discovered, most of which show monoperiodic variability in agreement with rotational modulation. Conclusions. Together with the recently published catalogue of APOGEE CP3 stars, our work significantly increases the sample size of known Galactic CP3 stars, paving the way for future in-depth statistical studies.

show abstract

“…Only spectra with a S/N of more than 50 in the Sloan g band were considered for further analysis. This cut was deemed necessary because a lower S/N renders the detection of mCP star features difficult (Paunzen et al 2011). If more than one spectrum was available for a single object, only the spectrum with the highest Sloan g band S/N was included into the analysis.…”

Section: Sample Selectionmentioning

confidence: 99%

A plethora of new, magnetic chemically peculiar stars from LAMOST DR4

Hümmerich

Paunzen

Bernhard

2020

A&A

Self Cite

View full text Add to dashboard Cite

Context. Magnetic chemically peculiar (mCP) stars are important to astrophysics because their complex atmospheres lend themselves perfectly to the investigation of the interplay between such diverse phenomena as atomic diffusion, magnetic fields, and stellar rotation. The most up-to-date catalogue of these objects was published a decade ago. Since then, no large scale spectroscopic surveys targeting this group of objects have been carried out. An increased sample size of mCP stars, however, is important for statistical studies. Aims. The present work is aimed at identifying new mCP stars using spectra collected by the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). Methods. Suitable candidates were selected by searching LAMOST DR4 spectra for the presence of the characteristic 5200 Å flux depression. Spectral classification was carried out with a modified version of the MKCLASS code and the accuracy of the classifications was estimated by comparison with results from manual classification and the literature. Using parallax data and photometry from Gaia DR2, we investigated the space distribution of our sample stars and their properties in the colour-magnitude diagram. Results. Our final sample consists of 1002 mCP stars, most of which are new discoveries (only 59 common entries with the Catalogue of Ap, HgMn and Am stars). Traditional mCP star peculiarities have been identified in all but 36 stars, highlighting the efficiency of the code’s peculiarity identification capabilities. The derived temperature and peculiarity types are in agreement with manually derived classifications and the literature. Our sample stars are between 100 Myr and 1 Gyr old, with the majority having masses between 2 M⊙ and 3 M⊙. Our results could be considered as strong evidence for an inhomogeneous age distribution among low-mass (M < 3 M⊙) mCP stars; however, we caution that our sample has not been selected on the basis of an unbiased, direct detection of a magnetic field. We identified several astrophysically interesting objects: the mCP stars LAMOST J122746.05+113635.3 and LAMOST J150331.87+093125.4 have distances and kinematical properties in agreement with halo stars; LAMOST J034306.74+495240.7 is an eclipsing binary system (Porb = 5.1435 ± 0.0012 d) hosting an mCP star component; and LAMOST J050146.85+383500.8 was found to be an SB2 system likely comprising of an mCP star and a supergiant component. Conclusions. With our work, we significantly increase the sample size of known Galactic mCP stars, paving the way for future in-depth statistical studies.

show abstract

New spectroscopic classifications of 35 chemically peculiar candidate stars

Cited by 11 publications

References 34 publications

A photometric study of chemically peculiar stars with the STEREO satellites - I. Magnetic chemically peculiar stars★

A photometric study of chemically peculiar stars with the STEREO satellites - I. Magnetic chemically peculiar stars★

New mercury-manganese stars and candidates from LAMOST DR4

A plethora of new, magnetic chemically peculiar stars from LAMOST DR4

Contact Info

Product

Resources

About