J/ApJ/941/143 SPYGLASS. III. Fornax-Hor assoc. & Austral complex (Kerr+, 2022)
SPYGLASS.
III. The Fornax-Horologium association and its traceback history within the
Austral Complex.
Kerr R., Kraus A.L., Murphy S.J., Krolikowski D.M., Bedding T.R.,
Rizzuto A.C.
<Astrophys. J., 941, 143 (2022)>
=2022ApJ...941..143K 2022ApJ...941..143K
ADC_Keywords: Associations, stellar; Radial velocities; Equivalent widths;
Stars, masses; YSOs; Parallaxes, trigonometric; Colors; Optical
Keywords: Stellar associations ; Stellar ages ; Star formation ;
Pre-main sequence stars
Abstract:
The study of young associations is essential for building a complete
record of local star formation processes. The Fornax-Horologium
association (FH), including the χ1 Fornacis cluster, represents
one of the nearest young stellar populations to the Sun. This
association has recently been linked to the Tuc-Hor, Carina, and
Columba associations, building an extensive "Austral Complex" almost
entirely within 150pc. Using Gaia astrometry and photometry in
addition to new spectroscopic observations, we perform the deepest
survey of FH to date, identifying over 300 candidate members, nearly
doubling the known population. By combining this sample with
literature surveys of the other constituent populations, we produce a
contiguous stellar population covering the entire Austral Complex,
allowing the definitions of subpopulations to be reassessed along with
connections to external populations. This analysis recovers new
definitions for FH, Tuc-Hor, Columba, and Carina, while also revealing
a connection between the Austral complex and the Sco-Cen-affiliated
Platais 8 cluster. This suggests that the Austral complex may be just
a small component of a much larger and more diverse star formation
event. Computing ages and tracing stellar populations back to
formation reveals two distinct nodes of cospatial and continuous
formation in the Austral Complex, one containing Tuc-Hor, and the
other containing FH, Carina, and Columba. This mirrors recent work
showing similar structure elsewhere, suggesting that these nodes,
which only emerge through the use of traceback, may represent the
clearest discrete unit of local star formation, and a key building
block needed to reconstruct larger star-forming events.
Description:
The initial selection of candidate Fornax-Horologium members is based
on the results of SPYGLASS-I (Kerr+ 2021, J/ApJ/917/23), which
identified 3x104 photometrically young stars within 333pc of the
solar system.
To complete literature RV sample (described in Section 2.2), we
obtained supplemental observations using the LCO NRES spectrograph,
which provides high-resolution (R=53000) spectra covering a spectral
range between 3400 and 10900Å. Exposure times ranged from 5-30min
depending on the star's magnitude.
A total of 37 targets were observed using the LCO 1m telescopes
across three of the network's nodes: the Wise Observatory (TLV),
South Africa Astronomical Observatory (CPT), and Cerro Tololo
Observatory (LSC).
See Section 2.3.
To determine pulsation frequencies for asteroseismic ages, we used
photometry from the Transiting Exoplanet Survey Satellite (TESS). The
data have 2 minutes cadence and were obtained from the Mikulski
Archive for Space Telescopes. See Section 2.6.
After combining all of our samples and removing eight duplicates found
in both our Fornax-Horologium sample and our literature-derived
catalog of Columba members, our sample size across all Austral
subassociations is 811. See Section 3.5.
Objects:
----------------------------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------------------------
03 27 00 -35 50 00 Fornax-Horologium = [KRK2021] Fornax-Horologium
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File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 91 628 Spectroscopic properties of members in Fornax-
Horologium and the connected Tuc-Hor, Columba, and
Carina associations
table2.dat 88 811 Stars identified as credible candidate members of
Fornax-Horologium and adjoining Austral populations
table5.dat 58 206 Binaries in the Austral complex (see Section 3.3)
refs.dat 106 43 References
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See also:
B/ocl : Optically visible open clusters and Candidates (Dias+ 2002-2015)
III/254 : 2nd Cat. of RVel with Astrometric Data (Kharchenko+, 2007)
V/137 : Extended Hipparcos Compilation (XHIP) (Anderson+, 2012)
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
III/279 : RAVE 5th data release (Kunder+, 2017)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/A+AS/135/503 : HIP southern B8-F2 stars radial velocities (Grenier+ 1999)
J/AJ/123/3356 : Palomar/MSU nearby star sp. survey. III. (Gizis+, 2002)
J/A+A/438/1163 : Catalogue of Open Cluster Data (COCD) (Kharchenko+, 2005)
J/AJ/132/866 : New M dwarfs in solar neighborhood (Riaz+, 2006)
J/A+A/460/695 : Associations Containing Young stars (Torres+, 2006)
J/AN/328/889 : Mean Radial Velocities of open clusters (Kharchenko+, 2007)
J/AJ/133/2524 : Spectra of young nearby stars (White+, 2007)
J/A+A/508/833 : SACY III. Li abundances (da Silva+, 2009)
J/ApJS/190/1 : A survey of stellar families (Raghavan+, 2010)
J/A+A/530/A138 : Geneva-Copenhagen survey re-analysis (Casagrande+, 2011)
J/ApJ/731/8 : Multiple star formation in Taurus-Auriga (Kraus+, 2011)
J/A+A/546/A61 : Radial velocities for XHIP catalogue (de Bruijne+, 2012)
J/A+A/551/A46 : Compiled phot. for Cham I & II members (Lopez Marti+, 2013)
J/ApJ/762/88 : Young stellar kinematic group cand. members (Malo+, 2013)
J/A+A/568/A26 : SACY. V. Multiple systems (Elliott+, 2014)
J/AJ/147/146 : Spectroscopy of Tuc-Hor candidate members (Kraus+, 2014)
J/ApJ/788/81 : BANYAN III. RVel & rotation of low-mass stars (Malo+, 2014)
J/MNRAS/454/593 : Young moving groups in solar neighbourhood (Bell+, 2015)
J/ApJS/220/18 : BDKP IV. RVs of M & L dwarfs with MagE (Burgasser+, 2015)
J/A+A/573/A126 : VLT/NaCo Large program I. Sample (Desidera+, 2015)
J/ApJS/225/10 : Kinematic analysis of M7-L8 dwarfs (Faherty+, 2016)
J/AJ/154/69 : ACRONYM II. β Pictoris Moving Group (Shkolnik+, 2017)
J/A+A/618/A93 : Gaia DR2 open clusters in the MW (Cantat-Gaudin+, 2018)
J/MNRAS/475/1960 : ESPaDOnS spectropolarimeter obs. of M dwarfs (Fouque+, 2018)
J/ApJ/862/138 : BANYAN. XIII. Young assoc. with Gaia DR2 (Gagne+, 2018)
J/ApJ/860/43 : BANYAN. XII. New members from Gaia-Tycho data (Gagne+, 2018)
J/ApJ/856/23 : BANYAN. XI. The BANYAN Σ algorithm (Gagne+, 2018)
J/A+A/614/A76 : CARMENES input catalogue of M dwarfs. III. (Jeffers+, 2018)
J/AJ/156/84 : APOGEE-2 survey of Orion Complex. II. (Kounkel+, 2018)
J/A+A/616/A7 : Gaia DR2 radial velocity standard stars (Soubiran+, 2018)
J/A+A/615/A12 : Nearby open clusters TGAS and HSOY reanalysis (Yen+, 2018)
J/A+A/620/A172 : Solar neighbourhood young stars 3D mapping (Zari+, 2018)
J/ApJ/877/60 : YMGs. I. Young binaries & lithium-rich stars (Bowler+, 2019)
J/A+A/621/A115 : Vela OB2 members (Cantat-Gaudin+, 2019)
J/AJ/158/122 : Local structure & SFH of the MW (Kounkel+, 2019)
J/ApJ/870/32 : Kinematics in young star clusters & assoc. (Kuhn+, 2019)
J/MNRAS/489/2189 : Nearby young moving groups with ML (Lee+, 2019)
J/AJ/157/234 : ACRONYM. III. Cand. young low-mass stars (Schneider+, 2019)
J/A+A/626/A31 : Radial velocities of nearby stars (Sperauskas+, 2019)
J/ApJS/245/34 : Abund. for 6 million stars from LAMOST DR5 (Xiang+, 2019)
J/A+A/654/A122 : X1 Fornacis cluster DANCe (Galli+, 2021)
J/ApJ/917/23 : SPYGLASS. I. Mapping young stellar structures (Kerr+, 2021)
J/MNRAS/513/5727 : Li study with GESiDR6's PMS stars cluster (Binks+, 2022)
J/A+A/664/A175 : MW low mass young stars from Gaia EDR3 (Prisinzano+, 2022)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
2- 20 I19 --- Gaia Gaia DR3 source identifier
22- 29 F8.4 deg RAdeg Right Ascension (ICRS) at Epoch=2016.0
31- 38 F8.4 deg DEdeg Declination (ICRS) at Epoch=2016.0
40- 45 F6.2 km/s RVel [-26/94]? Radial Velocity
47- 51 F5.2 km/s e_RVel [0/37.4]? Uncertainty in RVel
53- 57 A5 --- r_RVel Source for RVel (see refs.dat file)
59- 64 F6.3 0.1nm EWLi [-0.09/2.3]? Equivalent width, Lithium
66- 70 F5.3 0.1nm e_EWLi [0/1.9]? Uncertainty in EWLi
72- 75 A4 --- r_EWLi Source for EWLi (see refs.dat file)
77- 82 F6.2 0.1nm EWHb [-36.8/3.8]? Equivalent width, Hβ
84- 87 F4.2 0.1nm e_EWHb [0/1]? Uncertainty in EWHb
89- 91 A3 --- r_EWHb Source for EWHb (see refs.dat file)
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 I19 --- Gaia Gaia DR3 source identifier
21- 23 A3 --- Group Literature group the star was initially
assigned to (1)
25- 27 A3 --- Src Source the star was drawn from (2)
29 I1 --- Reg [1/6] ID of the HDBSCAN subgroup (3)
31- 38 F8.4 deg RAdeg Right Ascension (ICRS) at Epoch=2016.0
40- 47 F8.4 deg DEdeg Declination (ICRS) at Epoch=2016.0
49- 53 F5.2 mas plx [3.5/20] Gaia DR3 parallax
55- 59 F5.2 mag Gmag [-0.2/5]? Gaia DR3 G-band magnitude
61- 65 F5.2 mag GBP-GRP [5.9/63] Gaia DR3 GBP-GRP color
67- 70 F4.2 Msun Mstar [0.09/3.7] Mass
72- 75 F4.2 --- D [0/1] Clustering proximity
77 I1 --- A [0/1] Boolean solution to the Astrometric
quality cut from SPYGLASS-I (4)
79 I1 --- P [0/1] Boolean solution to the Photometric
quality cut from SPYGLASS-I (4)
81 I1 --- PY [0/1] Flag for the photometric youth
determination of the star (4)
83- 84 I2 --- V [-1/1] Flag to represent the results of our
velocity membership cuts (4)
87- 88 I2 --- F [0/10]? Flag for other notable features (4)
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Note (1): The literature group the star was initially assigned to. Stars
assigned to FH constitute the candidate member sample for
Fornax-Horologium produced by this publication.
FH = Fornax-Horologium association (329 occurrences)
THA = Tucana-Horologium Association (229 occurrences)
COL = Columba association (140 occurrences)
CAR = Carina association (110 occurrences)
SMT = (3 occurrences)
Note (2): The source the star was drawn from. The abbreviations are as follows:
F = the Fornax-Horologium association (FH) sample from this work;
T = Torres et al. (2008hsf2.book..757T 2008hsf2.book..757T)
M = Malo et al. (2013ApJ...762...88M 2013ApJ...762...88M)
K = Kraus et al. (2014AJ....147..146K 2014AJ....147..146K)
S = Schneider et al. (2019AJ....157..234S 2019AJ....157..234S)
11 = Gagne et al. (2018ApJ...862..138G 2018ApJ...862..138G)
12 = Gagne et al. (2018ApJ...860...43G 2018ApJ...860...43G)
13 = Gagne & Faherty (2018ApJ...862..138G 2018ApJ...862..138G)
B21 = Booth et al. (2021MNRAS.500.5552B 2021MNRAS.500.5552B)
Note (3): The ID of the HDBSCAN subgroup the star is assigned to.
Codes as follows:
1 = Columba (124 occurrences)
2 = Carina (101 occurrences)
3 = Tuc-Hor (220 occurrences)
4 = Fornax-Horologium association (FH; 329 occurrences)
5 = Group 5 (22 occurrences)
6 = Group 6, centered on the Sco-Cen-linked Platais 8 cluster
(15 occurrences)
Note (4): Generally, the flag 1 = passes the criteria; 0= fails. The
Astrometric quality is based on the unit weight error; The Photometric
quality cut is based on the BP/RP flux excess factor; Stars that fail
photometric youth cut (PY=0) are not included in this table. For the
velocity membership cuts, 1 passes, -1 fails, and 0 has no RV. A flag
for other notable features. 1 indicates that the star has a resolved
companion within 10000 AU in the plane of the sky, 2 indicates a bad
broadening function solution, 4 indicates a bimodal line profile likely
indicative of spectroscopic binarity, 8 indicates an RUWE>1.2,
indicating likely unresolved binarity. The flags are added in cases
where multiple are true; for example, flag 6 indicates both flag 2 and 4.
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Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 I19 --- Gaia Gaia DR3 source identifier
21- 23 I3 --- Syst [0/100] Sequential system identifier
25- 28 I4 au Sep [0/8533] Projected separation (1)
30- 37 F8.4 deg RAdeg Right Ascension (ICRS) at Epoch=2016.0
39- 46 F8.4 deg DEdeg Declination (ICRS) at Epoch=2016.0
48- 52 F5.2 mag Gmag [4.6/19.7] Gaia DR3 G-band magnitude
54- 58 F5.2 mas plx [6.6/34.3] Gaia DR3 parallax
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Note (1): Projected separation in astronomical units at the distance of the
primary relative to the primary. Primaries have a separation of zero.
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Byte-by-byte Description of file: refs.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 A5 --- Ref Reference code
7- 25 A19 --- Auth First author's name(s)
28- 46 A19 --- BibCode Bibcode of the reference
48-106 A59 --- Comm Comment
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History:
From electronic version of the journal
References:
Kerr et al. Paper I. 2021ApJ...917...23K 2021ApJ...917...23K Cat. J/ApJ/917/23
Kerr et al. Paper II. 2022ApJ...941...49K 2022ApJ...941...49K Cat. J/ApJ/941/49
Kerr et al. Paper III. 2022ApJ...941..143K 2022ApJ...941..143K This catalog
Kerr et al. Paper IV. 2023ApJ...954..134K 2023ApJ...954..134K Cat. J/ApJ/954/134
Kerr et al. Paper V. 2024ApJ...975...99K 2024ApJ...975...99K
Kerr et al. Paper VI. 2025ApJ...985..111K 2025ApJ...985..111K
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 02-Oct-2025