---

Size, Mass and Density of Asteroids (SiMDA)

Home | Catalog | More | Info

Designation

OR select from list: --------- 10P/Tempel_2 1991_VH 1994_CC 1996_FG3 1998_RO1 1998_SM165 1999_KW4 1999_OJ4 1999_TC36 19P/Borrely 1P/Halley 2000_DP107 2000_OJ67 2000_QL251 2000_UG11 2001_QC298 2001_QT297 2001_SN263 2001_XR254 2002_CE26 2003_QY90 2003_TJ58 2003_YT1 2004_DC 2004_PB108 22P/Kopff 2P/Encke 45P/H-M-P 46P/Wirtanen 67P/C-G 6P/dArrest 81P/Wild_2 9P/Tempel_1 Adelheid Adeona Adorea Adria Aegina Aegle Aemilia Aeria Aethra Aglaja Alauda Alekto Aletheia Alexandra Aline Alkeste Alkmene Amalthea Amherstia Ampella Amphitrite Anacostia Andromache Ani Antigone Antiope Apollonia Aquitania Ara Arachne Arethusa Argentina Ariadne Armenia Armida Arsinoe Artemis Asia Aspasia Asterope Astraea Atala Atalante Ate Athamantis Aurelia Aurora Ausonia Balam Bamberga Barbara Baucis Beatrix Bellona Bennu Berbericia Berna Bertha Bertholda Bettina Bilkis Bohlinia Boliviana Borasisi Bredichina Brixia Bruchsalia Budrosa Camilla Campania Cantabia Carina Carlova Cava Ceres Ceto Chaldaea Charybdis Cheruskia Chicago Chimaera Chloris Christa Chryseis Circe Comacina Concordia Corduba Cybele Dagmar Danae Daphne Davida De_Sitter Debussy Dembowska Denise Desiderata Devosa Diana Dido Didymos Dike Dione Dionysus Diotima Doris Dynamene Echo Edith Edna Egeria Eichsfeldia Ekard Elektra Eleonora Elfriede Elisabetha Elpis Emita Emma Eos Erato Erigone Eris Erminia Eros Eucharis Eudora Eugenia Eukrate Eunike Eunomia Euphrosyne Europa Eurydike Eurykleia Eurynome Euterpe Eva Evelyn Faina Felicitas Feronia Fides Flammario Flora Fortuna Freda Freia Frigga Fringilla Frostia Galatea Gallia Ganymed Genoveva Genua Gerlinde Germania Gratia Gudrun Gyptis Hamburga Harmonia Haumea Havnia Hebe Hedwig Hekate Hektor Hel Helio Henrietta Hera Herculina Hermentaria Hermione Hersilia Hertha Hesperia Hestia Hippo Hispania Hohensteina Honoria Huenna Hygiea Hypatia Ianthe Ida Iduna Ilmatar Industria Ino Interamnia Io Iphigenia Irene Iris Irma Irmgard Irmintraud Isabella Isberga Isis Isolda Itokawa Johanna Josephina Juewa Julia Juno Kalliope Kallisto Kalypso Kassandra Kleopatra Klio Klotho Klymene Klytaemnestra Kolga Kreusa Lacadiera Lachesis Laetitia Lamberta Lampetia Lanzia Laurentia Leda Lehigh Leonora Leto Leukothea Lictoria Liguria Lilaea Logos Lomia Loreley Lucina Ludmilla Luisa Lumen Lundia Luscinia Lutetia Lydia Mancunia Mandeville Marghanna Marianna Marion Martha Mashona Massalia Massinga Mathesis Mathilde Medea Megaira Melete Meliboea Melpomene Melusina Merapi Messalina Metis Minerva Miriam Misa Mnemosyne Mombasa Montague Myrrha Nausikaa Nemausa Nemesis Nephele Nephthys Ninina Niobe Notburga Nuwa Nysa Oceana Octavia Olga Olympia Ophelia Orcus Ornamenta Ostro Padua Palatia Pales Palisana Pallas Palma Panopaea Papagena Pariana Parthenope Patientia Patroclus Pax Peitho Penelope Peraga Phaeo Philomela Philosophia Phocaea Phthia Pickeringia Pluto Polyhymnia Polyxena Polyxo Pomona Pompeja Praxedis Pretoria Princetonia Prokne Proserpina Protogeneia Psyche Pulcova Pythia Quaoar Rachele Roberta Rosa Rusthawelia Ryugu SL9 Sabine Sapientia Sappho Scheila Sekhmet Semele Semiramis Sibylla Siegena Siwa Sophrosyne Stereoskopia Sulamitis Svea Sylvia Tama Tamara Tanete Tatjana Tauris Tekmessa Tercidina Terpsichore Thalia Themis Theobalda Thetis Thia Thisbe Thyra Tisiphone Titania Tokio Tolosa Tombecka Typhon Ulla Una Undina Unitas Urania Ursula Vanadis Vaticana Velleda Veritas Vesta Vibilia Victoria Vincentina Virginia Vundtia Winchester Wratislavia Xanthippe Zelinda

---

Introduction This system is an archive (data base) of published mass and diameter estimates of minor bodies of our Solar System (mainly asteroids, but also some comets, TNOs and dwarf planets). Currently 1764 mass and 4141 diameter estimates for 428 objects are archived. Status: The archive is yet not complete, especially volume-equivalent diameter from DAMIT has to be added and masses from some planetary ephemerides. Usage Enter in the form above the name of an asteroid (like for example Hermione or Psyche) or select an object from the drop down list. The average mass and diameter values are calculated interactively from the list of values in the tables. You can select / deselect entries (except there is only one value given) and (re-)calculate the average mass and / or the average diameter by clicking the "Update" button. The corresponding plot will be updated as well. Unselected values will be shown in light grey in the plot and are not used for the average calculation. The derived mean bulk density will be recalculated as well after you re-calculated either the average mass or the average diameter. The average mass and diameter values are calculated using the "Expected Value Method (EVM)" [1]. For comparison the summary table also gives the values derived using the well-known weighted average (w.avg). The disadvantage of the latter method is that a single estimate with underestimated errors can bias the average because of the strong weight it gets (w = 1/err^2). All errors are 1σ. Concerning the treatment of asymmetric errors for diameter and / or mass estimates here in SiMDA please refer to the info page. Cite Kretlow, M., 2020: Size, Mass and Density of Asteroids (SiMDA) - A Web Based Archive and Data Service. EPSC Abstracts Vol. 14, EPSC2020-690.

Densities The calculated bulk density (ρ) is based on the averaged values of the mass (M) and of the diameter (D), from which a volume of a sphere is calculated. Derived densities can be unrealitstic. Currently, the uncertainty of the mass estimate is in many cases the limiting factor for the reliability of the bulk density ρ, but if the mass estimate is accurate to ≈20%, the contribution of the uncertainty of the volume-equivalent diameter can overwhelm that of the mass. See [2] and also here. Diameter As the volume V of the object is ~D3 (D: volume-equivalent diameter), the derived density is sensitive to the (volume-equivalent) diameter D. Not all methods provide volume-equivalent diameters, like for example stellar occcultation profile fits. But combining them with 3D shape models yields to volume-equivalent sizes. Dyn and Tax Dynamical (orbit) classes (Dyn) used here are: COM, MBA (IMB, OMB, MCA etc.), NEA, CEN and TNO. Taxanomic classes (Tax) used here corresponds to the Tholen (1984+) scheme, the SMASSII Bus and Binzel (2002), the S3OS2 Lazarro+5 (2004), and the DeMeo+3 (2009) scheme. The data are taken from PDS (v4), and are given in the T.T, T.B , T.L (T:Tholen | B:Bus) and T.D columns of the summary table for the object. Contribution If you are missing a mass or size estimate which should be added into this data base please send me an email with the reference. If you find a bug please inform me as well. Thank you! References [1] M. Birch, B. Singh. Method of Best Representation for Averages in Data Evaluation. Nucl. Data Sheets 120, 106 (2014). DOI. [2] Carry, B., 2012 : Density of asteroids. Planetary and Space Science, Volume 73, Issue 1, p. 98-118. ADS.