J/ApJS/278/47 Exoplanets in the Antarctic Sky. V. AST3-II DR2 (Zhao+, 2025)
Exoplanets in the Antarctic Sky.
V. The second Data Release of AST3-II/CHESPA and newly found variables within
the Southern Continuous Viewing Zone of TESS.
Zhao B., Zhang H., Ashley M.C.B., Zhu J., Liu H., Yu Z., Zhou D., Ma B.,
Mould J., Wittenmyer R.A., Yuan X., Li Z., Li X., Fu J., Zhou J., Wang L.
<Astrophys. J. Suppl. Ser., 278, 47 (2025)>
=2025ApJS..278...47Z 2025ApJS..278...47Z
ADC_Keywords: Exoplanets; Stars, variable; Photometry; Optical; Stars, masses;
Surveys
Keywords: Binary stars ; Eclipsing binary stars ;
Astrometric exoplanet detection ; Sky surveys ; Catalogs ;
Photometric systems
Abstract:
Located at Dome A, the highest point on the Antarctic plateau, China's
Kunlun station is a premier ground-based photometric observatory. Its
cold, dry, and stable atmosphere allows continuous observation for
over 40 days during polar winter, ideal for detecting short-period
transiting exoplanets. Since 2008, the Antarctic Survey Telescopes
(AST3) project has pursued the CHESPA program to search for exoplanet
candidates. During the austral winters in 2016 and 2017, the AST3-II
telescope surveyed fields located in the southern continuous viewing
zone of the Transiting Exoplanet Survey Satellite (TESS). This paper
presents the second data release from CHESPA, encompassing photometric
data for over 85,000 bright (mi≤15) stars. The survey achieved a
photometric precision of approximately 2 mmag at optimal brightness
levels. To illustrate the data quality, we present a catalog of
203 newly identified variable stars showing brightness variations over
5 mmag based on the 2017 observations, as compared to Data Release 1.
Among these, 26 are newly recognized periodic variables that are not
listed in the AAVSO database (https://www.aavso.org/), and 86 are in
the TESS Candidate Target List. These variables required rigorous
examination to eliminate false-positive signals in the transiting
exoplanets search.
Description:
During the austral winter of 2017, we conducted a survey of selected
fields near the southern ecliptic pole and within the southern
continuous viewing zone (CVZ) of TESS using the Antarctic Survey
Telescopes (AST3)-II telescope at the Chinese Kunlun station, located
at Dome A, Antarctica. In this paper, we present the second data
release (DR2) of AST3-II (CHESPA) products obtained in austral winter
of 2017.
The AST3-II telescope, with an effective aperture of 50cm, enables
wide-field imaging over a 1.5x2.9deg2 field of view (in R.A. and
decl., respectively) with a spatial resolution of approximately 1"/pix.
It captures images in the Sloan i band.
See Section 2 and 3 for further explanations.
This release includes 203 newly identified variable stars compared to
DR1 (Zhang+ 2019, J/ApJS/240/16).
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 152 424 Variables from AST3-II (CHESPA) observation DR1 in
2016 and DR2 in 2017
lcs.dat 91 97262 AST3-II DR2 detrended light curves list;
table added by CDS
lightcurves/* . 32 Individual LC files in ASCII format
in 32 TESS Fields
--------------------------------------------------------------------------------
See also:
B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-)
II/336 : AAVSO Photometric All Sky Survey (APASS) DR9 (Henden+, 2016)
IV/38 : TESS Input Catalog - v8.0 (TIC-8) (Stassun+, 2019)
IV/39 : TESS Input Catalog version 8.2 (TIC v8.2) (Paegert+, 2021)
J/ApJ/628/411 : Identification and analysis of EBs (Devor+, 2005)
J/A+A/499/967 : Long-term monitoring of γ Dor stars (Cuypers+, 2009)
J/AJ/153/104 : Variables observed in the Gal. disk by AST3-1 (Wang+, 2017)
J/MNRAS/479/111 : AST3-1 Point Source Catalogue (Ma+, 2018)
J/AJ/156/102 : The TESS Input Catalog and Cand. Target List (Stassun+, 2018)
J/ApJS/240/16 : Exoplanets in the Antarctic sky. I. AST3-II DR1 (Zhang+, 2019)
J/ApJS/240/17 : Exoplanets in the Antarctic sky. II. (Zhang+, 2019)
J/AcA/73/127 : OGLE-IV Gal. bulge fields transiting planets (Mroz+, 2023)
http://casdc.china-vo.org/archive/ast3/II/dr2/ : Full data release
http://exoplanetarchive.ipac.caltech.edu/ : Exoplanet archive Caltech
http://www.aavso.org/ : AAVSO homepage
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- --- [AST3II]
7- 22 A16 --- AST3II Target identifier
(DDD.dddd+DD.dddd; J2000) (1)
27- 31 F5.2 mag imag [7.57/15.35] APASS catalog apparent i band
magnitude
33- 41 I9 --- TIC ? TESS Input Catalog Identifier (2)
43- 48 F6.3 mag Tmag [6.6/14.7]? TESS band apparent magnitude (2)
50- 58 F9.6 Rsun Rs [0.49/16.81]? Stellar radius (2)
60- 70 F11.9 Msun Ms [0.49/2.14]? Stellar mass (2)
72 I1 --- CTL [0/1] Candidate Target List flag (3)
74- 101 A28 --- AAVSO AAVSO notation
103- 111 F9.7 d PerA [0.07/5.53]? Period from AAVSO database
113- 127 A15 --- TypeA Type from AAVSO database (4)
129- 139 F11.9 d Per [0.048/6.13] AST3-II period
141- 148 A8 --- Type AST3-II type (5)
150- 152 A3 --- Cat Catalog identifier (6)
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Note (1): IDs of AST3-II targets in a format of "DDD.dddd+DD.dddd".
Sources in DR1 are <[ZYL2019] AST3II JDDD.dddd+DD.dddd> in Simbad.
Note (2): From the TIC (Stassun+ 2018, J/AJ/156/102).
Note (3): Flag as follows:
1 = target is also selected in the Candidate Target List
of TESS (Stassun+ 2017AJ....156..102S 2017AJ....156..102S; see Stassun+ 2018, J/AJ/156/102)
Note (4): VSX variable types are available at:
https://www.aavso.org/vsx/index.php?view=about.vartypes
Note (5): Variable star type designations following VSX:
CEP = Cepheids (33 occurrences + 3 "?")
CWB = W Virginis variables with periods shorter than 8 days. Also
known as BL Herculis variables (1 occurrence)
DSCT = Variables of the δ Scuti type (those with
amplitudes larger than 0.15 magnitude and asymetric
light curves are designated HADS) (35 occurrences + 2 "?")
EA(ED) = Algol eclipsing systems (40 occurrences + 1 "?")
EB(ESD) = Β Lyrae-type eclipsing systems (76 occurrences)
EW(EC) = W Ursae Majoris-type eclipsing variables (175 occurrences
+ 4 "?")
RR(RRAB/RRC) = Variables of the RR Lyrae type (58 occurrences)
There are a few occurrences with two classifications separated by "|" in
the table; note added by CDS.
Note (6): Catalogs of DR1 (Zhang+ 2019, J/ApJS/240/17; 221 occurrences) or
DR2 (this work; 203 occurrences).
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Byte-by-byte Description of file: lcs.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Field AST3-II field (Tess004 to Tess048)
9- 13 F5.2 mag imag [7/16] i-band magnitude in APASS database
15- 30 A16 --- AST3II Target identifier (DDD.dddd+DD.dddd; J2000) as
in Table 1
32- 79 A48 --- FileName File name in subdirectory: lightcurves/
Field/decorrapertureautocoadded0m/binned_1m/
epdbinnedtfa500svd8/tfastep2_data/
81- 91 F11.9 d Per [0.048/6.13]? AST3-II period from Table 1
--------------------------------------------------------------------------------
History:
From electronic version of the journal for Table 1
* ast3dr2binned1mtfa500svd8LCs.zip downloaded at:
https://casdc.china-vo.org/archive/ast3/II/dr2/
References:
Zhang et al. Paper I. 2019ApJS..240...16Z 2019ApJS..240...16Z Cat. J/ApJS/240/16
Zhang et al. Paper II. 2019ApJS..240...17Z 2019ApJS..240...17Z Cat. J/ApJS/240/17
Liang et al. Paper III. 2020AJ....159..201L 2020AJ....159..201L
Zhu et al. Paper IV. 2020AJ....159..172Z 2020AJ....159..172Z
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 18-Feb-2026