J/AJ/163/219 Gaia DR2 stellar flybys in the Sco-Cen OB association (Ma+, 2022)
Search for Stellar Flybys in the Sco-Cen OB Association with the Gaia DR2.
Ma Y., De Rosa R.J., Kalas P.
<Astron. J., 163, 219 (2022)>
=2022AJ....163..219M 2022AJ....163..219M
ADC_Keywords: Associations, stellar; Stars, masses; Radial velocities
Keywords: Celestial mechanics ; Close encounters ; Debris disks ;
Circumstellar disks
Abstract:
High-contrast imaging studies of debris disks have revealed a
significant diversity in their morphologies, including large-scale
asymmetries. Theories involving stellar flybys, an external source of
gravitational disturbance, have offered a plausible explanation for
the origin of these morphological variations. Our study is an
experiment to gain empirical evidence that has been lacking from such
theories. We explore this paradigm by using astrometric and radial
velocity measurements from the Gaia DR2 and ground-based observations
to trace the trajectories of 625 stars in the Sco-Cen OB association
from 5Myr in the past to 2Myr in the future. We identified 119 stars
that had at least one past flyby event occurring within one Hill
radius, and 23 of these experienced flybys within 0.5 Hill radii. We
found no evidence of a significant correlation between the presence of
flyby events and infrared excess detections, although the sample is
not uniformly sensitive to infrared excess emission. Ten stars that
had past flyby events host resolved circumstellar disks that appear
relatively symmetric in the existing data except for the circumbinary
disk surrounding HD106906. We determined the trajectory and relative
velocity of each of these flyby events and compared these to the
geometry of the spatially resolved disks. Future work is needed to
measure the kinematics of lower-mass stars and to improve sensitivity
to circumstellar disks for the entire sample.
Objects:
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RA (2000) DE Designation(s)
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16 15 -24.2 Sco-Cen = NAME Upper Sco-Cen
16 12 -23.4 USCO = NAME Upper Sco Association
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 123 67 Events identified from Sco-Cen sample
table3.dat 123 113 Events identified from USCO sample
table4.dat 105 76 Events involving candidates and field stars with
dca<1pc and vrel<10km/s
table5.dat 123 30 Simulated Potential Flyby events from USCO sample
table6.dat 119 462 RV measurements of 462 Sco-Cen stars
table7.dat 119 219 RV measurements of USCO sample
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See also:
B/wds : The Washington Visual Double Star Catalog (Mason+ 2001-2020)
III/190 : WEB Catalog of Radial Velocities (Duflot+ 1995)
III/254 : 2nd Cat. Radial Velocities with Astrometric Data (Kharchenko+, 2007)
III/272 : RAVE 4th data release (Kordopatis+, 2013)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/A+AS/118/231 : Velocities & rotation of CP stars (Levato+, 1996)
J/AJ/117/354 : OB associations from Hipparcos (de Zeeuw+, 1999)
J/A+A/356/541 : T Tauri stars in the Sco-Cen OB association (Koehler+, 2000)
J/A+A/460/695 : Search for Associations Containing Young stars (Torres+, 2006)
J/AN/328/889 : Mean Radial Velocities of open clusters (Kharchenko+, 2007)
J/A+A/480/L33 : Radial velocities of HD 4113 and HD 156846 (Tamuz+, 2008)
J/A+A/524/A25 : Radial Velocities on 6 exoplanet host stars (Triaud+, 2010)
J/ApJ/738/122 : ScoCen debris disks Around F- and G-type stars (Chen+, 2011)
J/ApJ/745/56 : Upper Sco members rotational velocities (Dahm+, 2012)
J/ApJ/758/31 : IR photometry for members of Upper Sco (Luhman+, 2012)
J/AJ/144/8 : Spectro. of ∼100 G/K/M-type Sco-Cen complex memb (Song+, 2012)
J/ApJS/208/9 : Intrinsic colors and temperatures of PMS stars (Pecaut+, 2013)
J/ApJ/785/47 : Sources around target stars Upper Scorpius (Lafreniere+, 2014)
J/A+A/573/A126 : VLT/NaCo Large program I. Sample (Desidera+, 2015)
J/ApJ/827/142 : ALMA observations of GKM stars in Upper Sco (Barenfeld+, 2016)
J/ApJS/225/15 : IR excess stars from Tycho-2 and AllWISE (Cotten+, 2016)
J/MNRAS/461/794 : Scorpius-Centaurus K-Type Stars (Pecaut+, 2016)
J/ApJ/840/87 : Young star systems observed with SALT (Riedel+, 2017)
J/A+A/616/A37 : Close encounters to the Sun in Gaia DR2 (Bailer-Jones+, 2018)
J/ApJ/856/23 : BANYAN. XI. The BANYAN Σ algorithm (Gagne+, 2018)
J/AJ/156/194 : Orbits double-lined pairs in multiple stars (Tokovinin, 2018)
J/A+A/623/A112 : The Sco OB2 population from Gaia DR2 data (Damiani+, 2019)
J/AJ/157/78 : Double &multiple star systems GaiaDR2 (Jimenez-Esteban+, 2019)
J/A+A/640/A73 : pi Men radial velocity curves (De Rosa+, 2020)
J/AJ/160/24 : Circumstellar dust of 104 stars with GPIES (Esposito+, 2020)
J/A+A/633/A82 : Disks around T Tauri stars with SPHERE. II. (Garufi+, 2020)
J/ApJS/247/66 : SUPERWIDE; wide binaries in Gaia & SUPERBLINK (Hartman+, 2020)
J/A+A/636/A116 : VLTI/PIONIER images of 15 Herbig Ae/Be stars (Kluska+, 2020)
J/AJ/160/44 : Upper Scorpius spectroscopy and photometry (Luhman+, 2020)
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Byte-by-byte Description of file: table[235].dat
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Bytes Format Units Label Explanations
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1- 23 A23 --- Star1 Star 1 identifier
25- 47 A23 --- Star2 Star 2 identifier
49- 53 F5.2 km/s RVel ? Simulated radial velocity (1)
55- 59 F5.2 Myr Tca Time of closest approach
61- 64 F4.2 Myr e_Tca Lower uncertainty in tca
66- 69 F4.2 Myr E_Tca Upper uncertainty in tca
71- 74 F4.2 pc Dca Distance of closest approach
76- 79 F4.2 pc e_Dca Lower uncertainty in dca
81- 84 F4.2 pc E_Dca Upper uncertainty in dca
86- 89 F4.2 --- dca/RH-T Ratio of closet approach to target Hill radius
91- 94 F4.2 --- e_dca/RH-T Lower uncertainty in dca/RH,T
96- 99 F4.2 --- E_dca/RH-T Upper uncertainty in dca/RH,T
101-104 F4.2 --- dca/RH-F Ratio of closet approach to flyby Hill radius
106-109 F4.2 --- e_dca/RH-F Lower uncertainty in dca/RH,F
111-114 F4.2 --- E_dca/RH-F Upper uncertainty in dca/RH,F
116-120 A5 --- Cat Category (2)
122-123 A2 --- IREx? Infrared excess detected (3)
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Note (1): For Simulated Potential Flyby (SPF) of the flyby star, which do not
have RVel measurement, that outputs the minimum dca.
Note (2): Categories as follows:
T = Ecounters with 0.5<dca/RH-T<1
F = Ecounters with 0.5<dca/RH-F<1
TF = Encounters satisfying both T and F conditions
F0.5 = dca/RH≤0.5, where RH is the Hill radius of flyby star
TF0.5 = dca/RH≤0.5, where RH is the Hill radius of both star and flyby
Note (3): Detections as follows:
T = The target star has IR excess detected
TF = The target star and the flyby have IR excess detected
According to Cotten & Song, 2016, J/ApJS/225/15.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 28 A28 --- Star1 Star 1 identifier (1)
30- 57 A28 --- Star2 Star 2 identifier (1)
59- 63 F5.2 Myr Tca [-2.43/2.05] Time of closest approach
65- 68 F4.2 Myr e_Tca [0.01/2.28] Lower uncertainty in tca
70- 73 F4.2 Myr E_Tca [0.01/2.28] Upper uncertainty in tca
75- 78 F4.2 pc Dca [0.02/0.99] Distance of closest approach
80- 83 F4.2 pc e_Dca [0.01/0.68] Lower uncertainty in dca
85- 88 F4.2 pc E_Dca [0.02/2.39] Upper uncertainty in dca
90- 93 F4.2 km/s Vrel [0.71/9.98] Flyby star's velocity vector (2)
95- 98 F4.2 km/s e_Vrel [0.1/5.84] Lower uncertainty in Vrel
100-103 F4.2 km/s E_Vrel [0.16/9.34] Upper uncertainty in Vrel
105-105 A1 --- Cat Category (3)
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Note (1): Star 1 are stars from the Sco-Cen sample and Star 2 are stars
from the candidate and field star population.
Note (2): In the rest frame of the target star.
Note (3): Categories as follows:
C = ScoCen-candidate encounter (66 occurrences)
F = ScoCen-field encounter (10 occurrences)
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Byte-by-byte Description of file: table[67].dat
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Bytes Format Units Label Explanations
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1- 24 A24 --- Target Target identifier
26- 44 I19 --- Gaia Gaia DR2 identifier
46- 60 A15 --- SpType Spectral type
62- 67 F6.3 Msun Mass ? Stellar mass
69- 71 A3 --- SubGrp ? Subgroup (1)
73- 78 F6.2 km/s GRVel ? Gaia DR2 radial velocity
80- 84 F5.2 km/s e_GRVel ? Uncertainty in GRVel
86- 92 F7.3 km/s RVel ? Literature radial velocity
94- 99 F6.3 km/s e_RVel ? Uncertainty in RVel
101-119 A19 --- r_RVel ADS bibcode reference for RVel
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Note (1): Group as follows:
LCC = Lower Centaurus-Crux
US = Upper Scorpius
UCL = Upper Centaurus-Lupus
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 12-Oct-2022