J/A+A/701/A242 R CrA formation history (Rigliaco+, 2025)
The Corona-Australis star-forming region.
New insights on its formation history from detailed stellar and disk analysis.
Rigliaco E., Gratton R., Nascimbeni V.
<Astron. Astrophys. 701, A242 (2025)>
=2025A&A...701A.242R 2025A&A...701A.242R (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Populations, stellar ; Stars, distances ;
Proper motions
Keywords: stars: formation - stars: general -
stars: stars: kinematics and dynamics
Abstract:
The star-forming complex of Corona Australis (CrA) is one of the
closest and most isolated molecular clouds. It belongs to a chain of
clusters that show age gradients with distance from the galactic
plane.
We aim to provide suggestions regarding its formation history by
examining the stellar and disk populations, the stellar multiplicity,
and the interstellar absorption.
We made a census of stars and disks using Gaia DR3 and infrared data.
Interstellar absorption in the direction of each star was derived by
comparing spectral types from the literature and Gaia colors. Stellar
multiplicity analysis accounts for both direct observation of visual
companions (Gaia data and high-contrast imaging) and indirect
detection of the presence of companions (eclipsing binaries,
spectroscopic binaries, and astrometry). The properties of the disks
were obtained from the slopes of the spectral energy distributions.
As found in previous studies, the CrA complex can be divided into two
regions: a younger region (CrA-Main: 3±1Myr) and an older one
(CrA-North: 6.7±0.3Myr), which are slightly younger than previously
thought. Moreover, while CrA-Main still appears bound to the gas,
CrA-North is unbound and expanding. The stars that belong to CrA-North
were in the most compact configuration 3.72Myr ago. At that time,
CrA-Main and CrA-North were also much closer to each other than they
appear now. The fraction of disk-bearing stars is higher in CrA-Main
than in CrA-North, as also expected due to the younger age of
CrA-Main.
We propose a formation history scenario for the CrA-complex. It
started between 15 and 18Myr ago with supernovae (SNe) explosions in
the Upper Centaurus-Lupus complex, followed by a quiescent phase with
little star formation. A star formation episode ∼7Myr ago formed
CrA-North stars. About 3.7Myr ago, a second SN explosion south of
CrA-North triggered star formation in CrA-Main. This last SN might
have been the origin of the pulsar RX J1856.5-3754.
Description:
Designations, proper motion and distances of the 442 stars considered
in this paper. 134 belong to the CRA-Main group and 308 belong to the
CrA-North group. of the CrA-Main and CrA-North stars. The full list of
the Gaia parameters, besides the proper motion and distances reported
in this table can be found in the Gaia Archive.
Stellar and disk properties of the CrA-Main and CrA-North stars.
Spectral type, mass, alpha disk index, dust mass, G-band extinction,
bp-rp color, G-band magnitude, G-H color and H-band magnitude are
reported for the 442 stars.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tableb1.dat 113 443 Designations, proper motion and distances of the
134 stars in CrA-Main and 308 stars in CrA-North
tableb2.dat 62 442 Stellar and disk properties of the CrA-Main
and CrA-North stars
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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- 6 A6 --- Run Run identification number or Pulsar
8- 17 A10 --- Group Belonging group
18- 37 A20 --- Name Designation
38- 68 A31 --- AName Alternative name(s)
70- 72 A3 --- --- [DR3- ]
74- 92 I19 --- GaiaDR3 ? Gaia DR3 name
94- 98 F5.2 mas/yr pmRA ?=- Proper motion along right ascension
100-105 F6.2 mas/yr pmDE ?=- Proper motion along declination
107-113 F7.3 pc Dist ?=- Distance
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Byte-by-byte Description of file: tableb2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Run Run identification number
5- 10 A6 --- SpType Spectral Type
12- 15 F4.2 Msun Mass ?=- Mass
17- 20 F4.2 --- alpha ?=- alpha disk index
22- 27 F6.2 Mgeo Mdust ?=- Dust mass of the disk in Earth masses
29- 32 F4.1 [Myr] logAge ?=- logarithm of the age
34- 38 F5.2 mag AG ?=- Extinction in G band
40- 44 F5.2 mag Bp-Rp ?=- Bp-Rp color
46- 50 F5.2 mag Gmag ?=- G-band magnitude
52- 56 F5.2 mag G-H ?=- G-H color
58- 62 F5.2 mag Hmag ?=- H-band magnitude
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Acknowledgements:
Elisabetta Rigliaco, elisabetta.rigliaco(at)inaf.it
INAF/Astronomical Observatory of Padua
(End) Elisabetta Rigliaco [INAF/Padua Obs.], Patricia Vannier [CDS] 30-Jul-2025