J/MNRAS/454/3267 Stellar encounters with long-period comets (Feng+, 2015)
Finding the imprints of stellar encounters in long-period comets.
Feng F., Bailer-Jones C.A.L.
<Mon. Not. R. Astron. Soc., 454, 3267-3276 (2015)>
=2015MNRAS.454.3267F 2015MNRAS.454.3267F (SIMBAD/NED BibCode)
ADC_Keywords: Solar system ; Comets
Keywords: celestial mechanics - Oort Cloud - Galaxy: kinematics and dynamics -
solar neighbourhood
Abstract:
The Solar system's Oort cloud can be perturbed by the Galactic tide
and by individual passing stars. These perturbations can inject Oort
cloud objects into the inner parts of the Solar system, where they may
be observed as the long-period comets (periods longer than 200yr).
Using dynamical simulations of the Oort cloud under the perturbing
effects of the tide and 61 known stellar encounters, we investigate
the link between long-period comets and encounters. We find that past
encounters were responsible for injecting at least 5 percent of the
currently known long-period comets. This is a lower limit due to the
incompleteness of known encounters. Although the Galactic tide seems
to play the dominant role in producing the observed long-period
comets, the non-uniform longitude distribution of the cometary
perihelia suggests the existence of strong - but as yet unidentified -
stellar encounters or other impulses. The strongest individual future
and past encounters are probably HIP 89825 (Gliese 710) and HIP 14473,
which contribute at most 8 and 6 percent to the total flux of
long-period comets, respectively. Our results show that the strength
of an encounter can be approximated well by a simple proxy, which will
be convenient for quickly identifying significant encounters in large
data sets. Our analysis also indicates a smaller population of the
Oort cloud than is usually assumed, which would bring the mass of the
solar nebula into line with planet formation theories.
Description:
We have conducted simulations of the perturbation of the Oort cloud in
order to estimate the significance of known encounters in generating
long-period comets.
We collected the data of stellar encounters from three sources:
(Bailer-Jones, 2015, Cat. J/A+A/575/A35, hereafter BJ15), Dybczynski &
Berski (2015MNRAS.449.2459D 2015MNRAS.449.2459D), and Mamajek et al.
(2015ApJ...800L..17M 2015ApJ...800L..17M).
Following BJ15, we use the term 'object' to refer to each encountering
star in our catalogue. A specific star may appear more than once but
with different data, thus leading to a different object.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 64 103 List of 103 encounter object
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See also:
J/A+A/575/A35 : Close star encounters (Bailer-Jones, 2015)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- HIP HIP number
8 A1 --- Cat [DGPRX] Catalog code (1)
10- 12 F3.1 Msun Menc Mass of the encountering star
14- 18 F5.2 Myr tph Time at perihelion of the
encountering star
20- 25 F6.2 km/s Vph Velocity at perihelion in the heliocentric
rest frame of the encountering star
27- 32 F6.3 pc dph Perihelion distance of the
encountering star
34- 38 F5.1 10-2Msun/pc2/km/s g g value (G=Menc/(dph2*Vph))
40- 42 I3 --- Ne Ne value (Ne=ηMenc/(dphdelta*Vph))
44- 48 F5.1 10+3 fmax Maximum flux ratio
50- 54 F5.2 Myr DTmax Time delay between the time when
encounter-induced flux reaches its
maximum and the perihelion time, tph
56- 60 F5.1 10+4 f0 Current flux ratio
62 A1 --- Seq [bnr] Sequence which an object belongs
to (2)
64 I1 --- r_Menc ? Reference to the stellar mass for the
45 most perturbing encounters (3)
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Note (1): Catalogue code as follows:
G = GCS, Holmberg et al., 2009A&A...501..941H 2009A&A...501..941H, Cat. V/130
R = RAVE, Kordopatis et al., 2013AJ....146..134K 2013AJ....146..134K, Cat. III/272
P = Pulkovo, Gontcharov, 2006AstL...32..759G 2006AstL...32..759G, Cat. III/252
X = XHIP, Anderson and Francis, 2012, Cat. V/137
D = Dybczynski & Berski (2015MNRAS.449.2459D 2015MNRAS.449.2459D)
Note (2): Sequence as follows:
r = objects in the reliable sequence, a subset of the basic
sequence with reliable data
b = objects in the basic sequence but not in the reliable sequence
n = objects in no sequence
Note (3): References as follows:
1 = mass was estimated according to the stellar type
2 = Garcia-Sanchez et al. (1999AJ....117.1042G 1999AJ....117.1042G)
3 = Rhee et al. (2007, Cat. J/ApJ/660/1556)
4 = Bailer-Jones (2015, Cat. J/A+A/575/A35)
5 = Thevenin et al. (2002A&A...392L...9T 2002A&A...392L...9T)
6 = De Rosa et al. (2012, Cat. J/MNRAS/422/2765)
7 = Liebert et al. (2005ApJ...630L..89G 2005ApJ...630L..89G)
8 = Malagnini & Morossi (1990A&AS...85.1015M 1990A&AS...85.1015M)
9 = Mamajek et al. (2015ApJ...800L..17M 2015ApJ...800L..17M)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 15-Jul-2016