J/ApJ/770/7 WISE/NEOWISE Main Belt asteroids: family members (Masiero+, 2013)
Asteroid family identification using the hierarchical clustering method and
WISE/NEOWISE physical properties.
Masiero J.R., Mainzer A.K., Bauer J.M., Grav T., Nugent C.R., Stevenson R.
<Astrophys. J., 770, 7 (2013)>
=2013ApJ...770....7M 2013ApJ...770....7M
ADC_Keywords: Minor planets ; Infrared sources ; Surveys
Keywords: minor planets, asteroids: general
Abstract:
Using albedos from WISE/NEOWISE to separate distinct albedo groups
within the Main Belt asteroids, we apply the Hierarchical Clustering
Method to these subpopulations and identify dynamically associated
clusters of asteroids. While this survey is limited to the ∼35% of
known Main Belt asteroids that were detected by NEOWISE, we present
the families linked from these objects as higher confidence
associations than can be obtained from dynamical linking alone. We
find that over one-third of the observed population of the Main Belt
is represented in the high-confidence cores of dynamical families. The
albedo distribution of family members differs significantly from the
albedo distribution of background objects in the same region of the
Main Belt; however, interpretation of this effect is complicated by
the incomplete identification of lower-confidence family members. In
total we link 38298 asteroids into 76 distinct families. This work
represents a critical step necessary to debias the albedo and size
distributions of asteroids in the Main Belt and understand the
formation and history of small bodies in our solar system.
Description:
In the first publication in this series (Masiero et al. 2011,
Cat. J/ApJ/741/68) we presented the preliminary results for Main Belt
asteroids (MBAs) from the Wide-field Infrared Survey Explorer (WISE)
thermal infrared all-sky survey (Wright et al. 2010AJ....140.1868W 2010AJ....140.1868W)
and the NEOWISE solar system enhancement to the core WISE mission
(Mainzer et al. 2011ApJ...731...53M 2011ApJ...731...53M).
In this paper we perform new analysis of the Main Belt using the
Hierarchical Clustering Method (HCM; Zappala et al.
1990AJ....100.2030Z 1990AJ....100.2030Z, 1994AJ....107..772Z 1994AJ....107..772Z, 1995Icar..116..291Z 1995Icar..116..291Z;
Bendjoya & Zappala 2002aste.conf..613B), taking into account dynamical
associations as well as asteroid albedo and diameter.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 90 76 Orbital elements, median and maximum diameters,
average albedos, and raw SFD slopes (α)
for observed asteroid families
table3.dat 60 38297 Orbital and physical parameters for Main Belt
asteroids associated with dynamical families
--------------------------------------------------------------------------------
See also:
J/A+A/569/A122 : Main-belt asteroids polarimetry. IV (Gil-Hutton+, 2014)
J/ApJ/760/L12 : WISE/NEOWISE NEOs preliminary thermal fits (Mainzer+, 2012)
J/ApJ/759/L8 : WISE/NEOWISE obs. of main belt asteroids (Masiero+, 2012)
J/ApJ/759/49 : WISE/NEOWISE Jovian Trojan asteroids: taxonomy (Grav+, 2012)
J/ApJ/744/197 : WISE/NEOWISE observations of Hilda asteroids (Grav+, 2012)
J/ApJ/743/156 : NEOWISE obs. of NEOs: preliminary results (Mainzer+, 2011)
J/ApJ/742/40 : Jovian Trojans asteroids with WISE/NEOWISE (Grav+, 2011)
J/ApJ/741/68 : Main Belt asteroids with WISE/NEOWISE. I. (Masiero+, 2011)
J/A+A/529/A86 : Polarimetric survey of main-belt asteroids (Gil-Hutton+, 2011)
http://hamilton.dm.unipi.it/astdys/index.php : AstDyS-2, Asteroids Dynamic Site
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 I05 --- Nfam [3/24649] ID number of family
7- 19 A13 --- Name Name of family
21 A1 --- f_Name [*] *: ambiguous parent bodies (1)
23- 25 I3 m/s Vlink [55/130] The HCM (Hierarchical Clustering
Method) velocity the family was extracted at
27- 32 F6.4 AU a [1.9/3.5] Median proper semimajor axis
34- 39 F6.4 --- e [0.01/0.3] Median eccentricity
41- 47 F7.4 deg i [0.6/27] Median inclination
49- 54 F6.2 km Dmax [5.9/469] Diameter of the largest body
56- 60 F5.2 km Dmed [1.6/10.3] Median diameter
62- 66 F5.3 --- pV [0/0.8] Average visible geometric albedo
68- 72 F5.3 --- e_pV [0.01/0.2] Error in pV
74- 79 F6.3 --- alpha [-5.2/-1.4] Raw size-frequency distribution
(SFD) slope αSFD (N∝Dα)
81- 85 F5.3 --- e_alpha [0.01/1.5] alpha uncertainty
87- 90 I4 --- N [40/5718] Number of linked family members
--------------------------------------------------------------------------------
Note (1): Cases of ambiguous parent bodies: either because there is no clear
largest body (e.g., Endymion) or there is a small group of objects of
similar sizes that could be the parent or represent a completely
shattered parent (e.g., the Eos family, where (221) Eos, (639) Latona,
and (579) Sidonia are clustered at similar semimajor axes with
diameters of D=96km, 89km, and 86km respectively). In some cases it is
clear that the listed family likely represents two overlapping
families (e.g., Emma). We also indicate Baptistina as an ambiguous
case given the results found in Masiero et al. (2012ApJ...759...14M 2012ApJ...759...14M).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- MPC Asteroid name in MPC format
9- 14 F6.4 AU a [1.9/3.6] Semimajor axis
16- 21 F6.4 --- e [0.005/0.3] Eccentricity
23- 29 F7.4 deg i [0.3/28] Inclination
31- 36 F6.2 km D [0.9/469] Infrared-measured diameter
38- 42 F5.2 km e_D Error in Diam
44- 48 F5.3 --- pV [0.004/1] Visible geometric albedo
50- 54 F5.3 --- e_pV Error in pV
56- 60 I05 --- Nfam ID number of family parent
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 18-Dec-2014