J/A+A/619/A116 New variables and 2 delta Scuti pulsations (Crouzet+, 2018)
Four winters of photometry with ASTEP South at Dome C, Antarctica.
Crouzet N., Chapellier E., Guillot T., Mekarnia D., Agabi A.,
Fantei-Caujolle Y., Abe L., Rivet J.-P., Schmider F.-X., Fressin F.,
Bondoux E., Challita Z., Pouzenc C., Valbousquet F., Bayliss D.,
Bonhomme S., Daban J.-B., Gouvret C., Blazit A.
<Astron. Astrophys. 619, A116 (2018)>
=2018A&A...619A.116C 2018A&A...619A.116C (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Asteroseismology
Keywords: methods: observational - methods: data analysis -
techniques: photometric - site testing -
stars: variables: delta Scuti - binaries: eclipsing
Abstract:
Dome C in Antarctica is a promising site for photometric observations
thanks to the continuous night during the Antarctic winter and
favorable weather conditions.
We developed instruments to assess the quality of this site for
photometry in the visible and to detect and characterize variable
objects through the Antarctic Search for Transiting ExoPlanets (ASTEP)
project.
Here, we present the full analysis of four winters of data collected
with ASTEP South, a 10cm refractor pointing continuously toward the
celestial south pole.
We achieved nearly continuous observations over the winters. We
improved the instrument over the years and developed specific data
reduction methods. We measure an average sky background of
20mag/arcsec2 in the 579-642nm bandpass. We built the lightcurves of
6000 stars and developed a model to infer the photometric quality of
Dome C from the lightcurves themselves. The weather is photometric
67.1±4.2% of the time and veiled 21.8±2.0% of the time. The
remaining time corresponds to poor quality data or winter storms.We
analyzed the lightcurves of Oct and HD 184465 and find that the
amplitude of their main frequency varies by a factor of 3.5 and 6.7
over the four years, respectively. We also identify 34 new variable
stars and eight new eclipsing binaries with periods ranging from 0.17
to 81 days.
The phase coverage that we achieved with ASTEP South is exceptional
for a ground-based instrument and the data quality enables the
detection and study of variable objects. These results demonstrate the
high quality of Dome C for photometry in the visible and for time
series observations in general.
Description:
tablec1.dat contains 36 new variable stars (ID, coordinates,
magnitude, variability parameters, variability type).
tablec2.dat contains 11 eclipsing binaries (ID, coordinates,
magnitude, eclipse parameters, eclipsing binary type). Eight are new
and three are known objects with improved classification and
parameters (see notes).
These objects were detected with ASTEP South at Dome C, Antarctica,
using stellar lightcurves obtained between 2008 and 2011 in a
4°x4° field of view centered on the celestial south pole.
tableb1.dat contains the 21 main frequencies detected in the Fourier
spectrum of sigma Oct with their amplitudes and phases.
tableb2.dat contains the amplitude of the ten main delta Scuti
frequencies found in the Fourier spectrum of sigma Oct for each winter
and for the four winters together.
tableb3.dat contains the amplitude of the ten delta Scuti frequencies
with signal to noise ratios greater than four found in the Fourier
spectrum of HD 184465 for each winter and for the four winters
together.
tableb4.dat contains the amplitude variations of three delta Scuti
frequencies of HD 184465 over the four winters, with two time
intervals for each of the 2008, 2009, and 2010 winters and six 30-day
intervals for the 2011 winter.
These objects were analyzed using lightcurves obtained by ASTEP South
at Dome C, Antarctica over four winters between 2008 and 2011.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablec1.dat 84 34 List of new variable stars
tablec2.dat 95 11 List of eclipsing binaries
listb.dat 57 2 List of tables with sigma Ori and HD 184465
frequencies
tableb1.dat 37 21 21 main frequencies of sigma Oct
tableb2.dat 62 10 Amplitude of the ten main delta Scuti frequencies
of sigma Oct over four winters
tableb3.dat 62 10 Amplitude of the ten main delta Scuti frequencies
of HD 184465 over four winters
tableb4.dat 23 12 Amplitude variations of three delta Scuti
frequencies of HD 184465 over four winters
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See also:
I/315 : UCAC3 Catalogue (Zacharias+ 2009)
Byte-by-byte Description of file: tablec1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- ID Name of the source in the UCAC3 catalog
(Cat. I/315)
12- 13 I2 h RAh Right ascension (J2000)
15- 16 I2 min RAm Right ascension (J2000)
18- 23 F6.3 s RAs Right ascension (J2000)
25 A1 --- DE- Declination sign (J2000)
26- 27 I2 deg DEd Declination (J2000)
29- 30 I2 arcmin DEm Declination (J2000)
32- 36 F5.2 arcsec DEs Declination (J2000)
38- 42 F5.2 mag fmag UCAC3 magnitude
44- 50 F7.5 1/d Freq Frequency
52- 57 F6.5 1/d e_Freq Frequency uncertainty
59- 63 F5.2 d Per Period
65- 68 F4.1 mmag Amp Amplitude
70- 72 F3.1 mmag e_Amp Amplitude uncertainty
74- 84 A11 --- Type Variability type (1)
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Note (1): Variability types as follows:
VRot = rotational variable
VRot? = tentative classification as rotational variable
Var = the type cannot be determined
delta Scuti = delta Scuti variable
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Byte-by-byte Description of file: tablec2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- ID Name of the source in the UCAC3 catalog
(Cat. I/315)
12- 13 I2 h RAh Right ascension (J2000)
15- 16 I2 min RAm Right ascension (J2000)
18- 23 F6.3 s RAs Right ascension (J2000)
25 A1 --- DE- Declination sign (J2000)
26- 27 I2 deg DEd Declination (J2000)
29- 30 I2 arcmin DEm Declination (J2000)
32- 36 F5.2 arcsec DEs Declination (J2000)
38- 42 F5.2 mag fmag UCAC3 magnitude
44- 54 F11.8 d Per Period
56- 64 F9.8 d e_Per Period uncertainty
66- 74 F9.4 d T0 Time of mid-eclipse (BJD-2450000)
76- 80 F5.4 d e_T0 Time of mid-eclipse uncertainty
82- 86 F5.1 mmag Dep Eclipse depth
88- 90 F3.1 mmag e_Dep Eclipse depth uncertainty
92- 93 A2 --- Type Eclipsing binary type
95 A1 --- Note [*] * indicates an individual note (1)
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Note (1): Notes as follows:
003-001765 = was reported as a rotating ellipsoidal variable by
Wang et al., 2015, Cat. J/ApJS/218/20.
004-000272 = was reported as a variable of unknown type by Wang et al., 2011,
Cat. J/AJ/142/155 was not identified by Wang et al., 2013, Cat. J/AJ/146/139.
001-000823 = is EN Oct: we improved its period and eclipse depth compared
to previous studies by Knigge et al. (1967BamVe...6...45K 1967BamVe...6...45K),
Otero (2004IBVS.5532....1O 2004IBVS.5532....1O).
002-003056 = is discussed in Sect. 7.5.2 of the paper.
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Byte-by-byte Description of file: listb.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 h RAh Right ascension (J2000)
4- 5 I2 min RAm Right ascension (J2000)
7- 11 F5.2 s RAs Right ascension (J2000)
13 A1 --- DE- Declination sign (J2000)
14- 15 I2 deg DEd Declination (J2000)
17- 18 I2 arcmin DEm Declination (J2000)
20- 23 F4.1 arcsec DEs Declination (J2000)
25- 33 A9 --- Name Star name
35- 45 A11 ---- FileName1 Name of the file with frequencies
47- 57 A11 --- FileName2 Name of the second file with frequencies
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Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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1- 9 F9.6 1/d Freq Frequency
11- 17 F7.6 1/d e_Freq Frequency uncertainty
19- 22 F4.2 mmag Amp Amplitude
24- 26 F3.2 mmag e_Amp Amplitude uncertainty
28- 32 F5.3 rad Phase Phase (BJD-2454600) (1)
34- 37 F4.3 rad e_Phase Phase uncertainty
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Note (1): The reference for the phase is BJD 2454600.
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Byte-by-byte Description of file: tableb2.dat tableb3.dat
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Bytes Format Units Label Explanations
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1- 9 F9.6 1/d Freq Frequency
11- 17 F7.6 1/d e_Freq Frequency uncertainty
19- 22 F4.2 mmag A08 Amplitude for the 2008 winter
24- 26 F3.2 mmag e_A08 Amplitude uncertainty for the 2008 winter
28- 31 F4.2 mmag A09 Amplitude for the 2009 winter
33- 35 F3.2 mmag e_A09 Amplitude uncertainty for the 2009 winter
37- 40 F4.2 mmag A10 Amplitude for the 2010 winter
42- 44 F3.2 mmag e_A10 Amplitude uncertainty for the 2010 winter
46- 49 F4.2 mmag A11 Amplitude for the 2011 winter
51- 53 F3.2 mmag e_A11 Amplitude uncertainty for the 2011 winter
55- 58 F4.2 mmag A08-11 Amplitude for the winters 2008 to 2011 together
60- 62 F3.2 mmag e_A08-11 Amplitude uncertainty for the winters
2008 to 2011 together
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Byte-by-byte Description of file: tableb4.dat
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Bytes Format Units Label Explanations
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1- 4 I4 d JD Time (JD-2450000)
6- 9 F4.2 mmag A9.671 Amplitude of the 9.671d-1 frequency
11- 14 F4.2 mmag A8.692 Amplitude of the 8.692d-1 frequency
16- 19 F4.2 mmag A6.465 Amplitude of the 6.465d-1 frequency
21- 23 F3.2 mmag e_A Amplitude uncertainty
(same for all amplitudes at a given time)
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Acknowledgements:
Nicolas Crouzet, nicolas.crouzet(at)iac.es
(End) Patricia Vannier [CDS] 20-Aug-2018