Radio stars observed in the LAMOST spectral survey

Zhang, Liyun; Yue, Qiang; Lu, Hongpeng; Han, Xianming L.; Zhang, Yong; Shi, Jianrong; Wang, Yuefei; Hou, Yonghui; Cao, Zihuang

doi:10.1088/1674-4527/17/10/105

Cited by 7 publications

(5 citation statements)

References 63 publications

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“…If the EW value of the Hα line was above 0 Å and simultaneously larger than the errors and the value of the height of the Hα line was three times larger than the standard error [34], we considered the behavior of the Hα line to be emission. However, the EW must be larger than 0.75 Å, because there are numerous molecular lines for M-type stars [23,31]. We have listed the EW of Hβ in the 11th column of Table 1 and the radio intensities at 4.8 GHz and 23 GHz in the 12th and 13th columns of Table 1.…”

Section: Lamost Low-resolution Spectroscopic Analysesmentioning

confidence: 99%

“…Similar to Table 1, we list the parameters of the radio stars with repeated spectra in Table 2. The amplitude of the Hα EW variability is three times larger than the error, and we considered the radio star as a variable [23]. Among them, 69 objects show a long time variation in their Hα intensity.…”

Section: Lamost Low-resolution Spectroscopic Analysesmentioning

confidence: 99%

“…The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) has recently offered stellar parameters from low and medium-resolution spectra [15][16][17], which are extremely useful for studying the chromospheric activity of solar-like stars and other chromospheric active stars in the Hα and Ca II IRT lines [18][19][20][21][22]. Zhang et al (2017) [23] analyzed 147 spectra of 89 active radio stars in the catalogue of radio stars using the LAM-OST low resolution survey DR2. They found that 28 stars exhibited long-term variation of chromospheric activity among 36 objects.…”

Section: Introductionmentioning

confidence: 99%

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Physical Properties of Radio Stars Based on LAMOST Spectral Survey

et al. 2022

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Radio emission has been detected for all types of stars in the Hertzsprung Russell diagram. Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) low and medium-resolution spectroscopic surveys provide a good opportunity to obtain the spectroscopic properties of radio stars. We cross-matched big data from the LAMOST DR7 low resolution spectral survey with a catalogue of radio stars, and obtained 449 stellar spectra of 258 stars. We detected 185 spectra with Hα emission. There are a total of 108 objects with repeated low resolution spectral observations, of which 63 show variations in the Hα line over a long time, about several months. We cross-matched LAMOST DR7 medium resolution spectra with the radio star catalogue. We obtained 1319 LAMOST medium-resolution spectra of the 156 radio stars and then calculated their equivalent widths (EWs) of the Hα line. Among them, 93 radio stars with Hα emission were found from the LAMOST medium resolution spectra, and 63 objects showed short and long-term variabilities, especially on a short time scale of approximately 20 min. Finally, we estimated the minimal detectable radio flux of the FAST telescope and provided a scientific plan for studying radio stars.

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Section: Lamost Low-resolution Spectroscopic Analysesmentioning

confidence: 99%

Section: Lamost Low-resolution Spectroscopic Analysesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Physical Properties of Radio Stars Based on LAMOST Spectral Survey

et al. 2022

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“…A high level of magnetic activity was believed to exist in VZ Psc (Wolff et al 1965). To test this hypothesis, we analyzed its spectrum from the LAMOST survey to investigate chromospheric activity (Zhang et al 2017). We analyzed its normalized spectrum using the spectral subtraction method by the program STARMOD (Barden 1985;Montes et al 1995).…”

Section: Photometric Analysis and Spectral Analysismentioning

confidence: 99%

Orbital parameters and period variation studies of the short-period eclipsing binaries FG Sct, VZ Lib and VZ Psc

Yue

Zhang

Han

et al. 2019

Res. Astron. Astrophys.

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We present eight sets of new light curves for binaries FG Sct, VZ Lib and VZ Psc, which are all contact eclipsing binaries with short orbital periods. We carried out our observations from 2016 to 2017 using the 60-cm telescope administered by National Astronomical Observatories, Chinese Academy of Sciences, the Holcomb Observatory at Butler University and the SARA-CT telescope in Chile. We firstly determined the orbital parameters of FG Sct using the O − C method and obtained photometric solutions utilizing the updated W-D program. We also studied its period variation and discovered that its orbital period is decreasing at a rate of 6.39(±0.24) × 10−8 d yr−1, which was likely caused by mass transfer from the primary component to the secondary component or angular momentum interchange between the two components via magnetic interactions. For VZ Lib and VZ Psc, we simultaneously analyzed their BV RI light curves in conjunction with the published radial velocities. In order to obtain the orbital parameters of VZ Lib, we also analyzed its period variation and revised cyclic change, which could be attributed to either the light-time effect due to a tertiary companion or magnetic activity cycle mechanism. We derived the periods of the tertiary component of VZ Lib to be 48.7(±0.1) yr or magnetic cycle to be 46.9(±1.9) yr. Strong emission lines at Ca ii H+K, Hα, Hβ, Hγ and Ca ii IRT were detected in the LAMOST spectra of VZ Psc, which imply chromospheric activities in this binary system.

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“…We also identified 33 objects with repeated observations. We further determined spectral EW variability by the difference in the maximum and minimum EWs in the Hα line: When this difference is larger than three times its corresponding error (Zhang et al 2016(Zhang et al , 2017, we consider the object's spectrum to be variable. Among these 33 objects, 30 CVs showed spectral variations, while three objects showed no spectral variation.…”

Section: Spectroscopic Properties Of Cvsmentioning

confidence: 99%

Cataclysmic variables based on the stellar spectral survey LAMOST DR3

Han

Zhang

Shi

et al. 2018

Res. Astron. Astrophys.

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Big data in the form of stellar spectra from the spectroscopic survey associated with the Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST) are important for studying properties of cataclysmic variables (CVs). By cross matching the catalogs of CVs compiled with LAMOST DR3, acquired from October 2011 to July 2015, we obtained the first spectroscopic catalog for CVs observed by LAMOST with high signal to noise ratio, above 8. By integrating line profiles, their equivalent widths (EWs) of the Hα, Hβ, Hγ and Hδ, as well as He I 5876 and 6678 Å lines, were calculated. There were 74 stellar spectra from 48 known CVs and three spectra from three new CV candidates. At the same time, we also collected their previously published EWs. Thirty-three objects had repeated spectra and 30 stars showed spectral variability in the Hα line. Moreover, we carried out photometric follow-up studies for five CVs (UU Aqr, TT Tri, PX And, BP Lyn and RW Tri). We obtained nine new light curves and revised their linear ephemerides. For RW Tri, there is a possible oscillation with an amplitude of 0.0031(2) days and a period of 47.6 ± 0.4 years, which might be caused by a third body (brown dwarf) or magnetic activity cycle.

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Radio stars observed in the LAMOST spectral survey

Cited by 7 publications

References 63 publications

Physical Properties of Radio Stars Based on LAMOST Spectral Survey

Physical Properties of Radio Stars Based on LAMOST Spectral Survey

Orbital parameters and period variation studies of the short-period eclipsing binaries FG Sct, VZ Lib and VZ Psc

Cataclysmic variables based on the stellar spectral survey LAMOST DR3

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