J/A+A/575/A35 Close star encounters (Bailer-Jones, 2015)
Close encounters of the stellar kind.
Bailer-Jones C.A.L.
<Astron. Astrophys. 575, A35 (2015)>
=2015A&A...575A..35B 2015A&A...575A..35B
ADC_Keywords: Positional data ; Solar system ; Stars, nearby
Keywords: comets: general - methods: numerical -
stars: kinematics and dynamics - stars: general - methods: numerical -
Oort cloud
Abstract:
Stars which pass close to the Sun can perturb the Oort cloud,
injecting comets into the inner solar system where they may collide
with the Earth. Using van Leeuwen's re-reduction of the Hipparcos
data complemented by the original Hipparcos and Tycho-2 catalogues,
along with recent radial velocity surveys, I integrate the orbits of
over 50000 stars through the Galaxy to look for close encounters. The
search uses a Monte Carlo sampling of the covariance of the data in
order to properly characterize the uncertainties in the times,
distances, and speeds of the encounters.
Description:
The table gives the perihelion (closest approach) parameters of stars
in the Hipparcos-2 catalogue (I/311) which are found by numerical
integration through a Galactic potential to approach within 10pc of
the Sun. These parameters are the time (relative to the Hipparcos
measurement epoch), heliocentric distance, and heliocentric speed of
the star at perihelion. Uncertainties in these have been calculated by
a Monte Carlo sampling of the data to give the Bayesian posterior
probability density function (PDF) over the parameters. For each
parameter, three summary values of this PDF are reported: the mean,
the 5% lower bound, the 95% upper bound. The latter two give a
Bayesian 90% confidence interval. The table also reports the
probability that each star approaches the Sun within 0.5, 1.0, and
2.0pc, as well as the measured parallax, proper motion, and radial
velocity (plus uncertainties) of the stars. Table 3 in the article
lists the first 65 lines of this data table (mean perihelion distance
below 2pc).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 158 1548 Perihelion parameters for all objects with a mean
perihelion distance below 10pc, in order of
increasing mean perihelion distance
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See also:
I/311 : Hipparcos, the New Reduction (van Leeuwen, 2007)
III/252 : Pulkovo radial velocities for 35493 HIP stars (Gontcharov, 2006)
III/272 : RAVE 4th data release (Kordopatis+, 2013)
V/137 : Extended Hipparcos Compilation (XHIP) (Anderson+, 2012)
J/A+A/530/A138 : Geneva-Copenhagen survey re-analysis (Casagrande+, 2011)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- HIP Hipparcos star identifier
8 A1 --- Cat [gprx] Catalogue identifier
(source of input data) (1)
10- 19 F10.3 kyr t.ph [-8912/15140] Mean perihelion time
21- 30 F10.3 kyr b_t.ph 5% bound on perihelion time distribution
32- 41 F10.3 kyr B_t.ph 95% bound on perihelion time distribution
44- 49 F6.3 pc d.ph [0.1/10] Mean perihelion distance
52- 57 F6.3 pc b_d.ph 5% bound on perihelion distance distribution
60- 65 F6.3 pc B_d.ph 95% bound on perihelion distance distribution
69- 74 F6.2 km/s v.ph [4/975] Mean perihelion speed
78- 83 F6.2 km/s b_v.ph 5% bound on perihelion speed distribution
86- 92 F7.2 km/s B_v.ph 95% bound on perihelion speed distribution
95- 96 I2 % f0.5 [0/100] Probability star approaches within 0.5pc
98-100 I3 % f1.0 [0/100] Probability star approaches within 1.0pc
102-104 I3 % f2.0 [0/100] Probability star approaches within 2.0pc
107-113 F7.2 mas Plx [3/797] Star Parallax
116-122 F7.2 mas e_Plx Parallax uncertainty (1σ)
124-131 F8.2 mas/yr pm Total proper motion
134-140 F7.2 mas/yr e_pm Proper motion uncertainty (1σ)
143-149 F7.2 km/s RV Radial velocity
152-158 F7.2 km/s e_RV Radial velocity uncertainty (1σ)
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Note (1): Code for source of input data as follows:
g = hip2gcs, cross-match between HIP2 (I/311) and GCS (J/A+A/530/A138)
p = hip2pulkovo, cross-match between HIP2 (I/311) and Pulkovo (III/252)
r = hip2rave, cross-match between HIP2 (I/311) and RAVE-DR4 (III/272)
x = xhip, XHIP (V/137)
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Acknowledgements:
Coryn Bailer-Jones, calj(at)mpia.de
(End) Coryn Bailer-Jones [MPIA, Heidelberg], Patricia Vannier [CDS] 15-Dec-2014