DOCSLIB.ORG

The Veritas and Themis Asteroid Families: 5-14Μm Spectra with The

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Veritas and Themis Asteroid Families: 5-14Μm Spectra with The Icarus 269 (2016) 62–74 Contents lists available at ScienceDirect Icarus journal homepage: www.elsevier.com/locate/icarus The Veritas and Themis asteroid families: 5–14 μm spectra with the Spitzer Space Telescope Zoe A. Landsman a,∗, Javier Licandro b,c, Humberto Campins a, Julie Ziffer d, Mario de Prá e, Dale P. Cruikshank f a Department of Physics, University of Central Florida, 4111 Libra Drive, PS 430, Orlando, FL 32826, United States b Instituto de Astrofísica de Canarias, C/Vía Láctea s/n, 38205, La Laguna, Tenerife, Spain c Departamento de Astrofísica, Universidad de La Laguna, E-38205, La Laguna, Tenerife, Spain d Department of Physics, University of Southern Maine, 96 Falmouth St, Portland, ME 04103, United States e Observatório Nacional, R. General José Cristino, 77 - Imperial de São Cristóvão, Rio de Janeiro, RJ 20921-400, Brazil f NASA Ames Research Center, MS 245-6, Moffett Field, CA 94035, United States article info abstract Article history: Spectroscopic investigations of primitive asteroid families constrain family evolution and composition and Received 18 October 2015 conditions in the solar nebula, and reveal information about past and present distributions of volatiles in Revised 30 December 2015 the solar system. Visible and near-infrared studies of primitive asteroid families have shown spectral di- Accepted 8 January 2016 versity between and within families. Here, we aim to better understand the composition and physical Available online 14 January 2016 properties of two primitive families with vastly different ages: ancient Themis (∼2.5 Gyr) and young Ver- Keywords: itas (∼8 Myr). We analyzed the 5 – 14 μm Spitzer Space Telescope spectra of 11 Themis-family asteroids, Asteroids including eight previously studied by Licandro et al. (2012), and nine Veritas-family asteroids, for a to- Asteroids tal of 20 asteroids in our sample. We detect a broad 10-μm emission feature, attributed to fine-grained composition and/or porous silicate regolith, in all 11 Themis-family spectra and six of nine Veritas-family asteroids, Asteroids with 10-μm spectral contrast ranging from 1% ± 0.1% to 8.5% ± 0.9%. We used thermal modeling to de- surfaces rive diameters, beaming parameters and albedos for our sample. Asteroids in both families have beaming Infrared observations parameters near unity and geometric albedos in the range 0.03 – 0.14. Spectral contrast of the 10-μm Spectroscopy silicate emission feature is correlated with beaming parameter and rotation period in the Themis family, and may be related to near-infrared spectral slope for both families. We see no correlations of 10-μm emission with diameter or albedo for either family. Comparison with laboratory spectra of primitive me- teorites suggests these asteroids are similar to meteorites with relatively low abundances of phyllosili- cates. Overall, our results suggest the Themis and Veritas families are primitive asteroids with variation in composition and/or regolith properties within both families. © 2016 Elsevier Inc. All rights reserved. 1. Introduction and even water ice (e.g., Campins et al., 2010; Rivkin and Emery, 2010; Licandro et al., 2011a). The study of primitive asteroids Asteroid families are the remnants of catastrophic collisions. provides constraints on models of solar system formation and Family members share similar orbits and cluster in the parameter evolution and is relevant to the origin of Earth’s water and life. space of their proper orbital elements. Spectroscopy of asteroid Themis and Veritas are two compositionally primitive families families can be diagnostic of composition and degree of aqueous residing in the outer main belt, with low inclinations and low alteration, and spectral hetero- or homogeneity within a family eccentricities (Fig. 1). The Veritas asteroid family is dynamically can reveal the state of differentiation of the parent body (Cellino young, 8.3 ± 0.5 Myr (Nesvorný et al., 2003). In a study of visible et al., 2002). Primitive asteroid families are of particular interest (0.4–0.9μm) spectroscopy from large surveys, Mothé-Diniz et al. because they represent a record of conditions in the early solar (2005) reported homogeneity among the Veritas asteroids, with all system. These bodies contain organic materials, hydrated minerals, Veritas members in the study falling within the C taxonomic com- plex. Previously, Di Martino et al. (1997) hadreportedevidencefor both C and D types among the Veritas asteroids. At ∼2.5 Gyr, the Themis family falls at the opposite dynamical ∗ Corresponding author. Tel.: +1 4078232325. E-mail address: [email protected] (Z.A. Landsman). age extreme (Marzari et al., 1995; Nesvorný et al., 2003). Themis http://dx.doi.org/10.1016/j.icarus.2016.01.008 0019-1035/© 2016 Elsevier Inc. All rights reserved. Z.A. Landsman et al. / Icarus 269 (2016) 62–74 63 Fig. 1. The Themis and Veritas asteroid families in the parameter spaces of the sine of inclination vs. semimajor axis (left) and the sine of inclination vs. eccentricity (right). family members studied with visible spectroscopy are typically B- vibrational modes in silicates, is sensitive to grain size, porosity types and C-types, with a smaller number of X-types, consistent and mineralogy (e.g., Emery et al., 2006; Vernazza et al., 2012). with a parent body mineralogy similar to CM meteorites (Florczak Additionally, the mid-IR may be diagnostic of degree of aque- et al., 1999; Mothé-Diniz et al., 2005). A visible and near-infrared ous alteration. In a study of primitive meteorites, McAdam et al. spectroscopic study of the Themis family and a young ( < 10 Myr) (2015) found that an emissivity minimum around 12 μm is cor- sub-family, Beagle, shows a range of spectral slopes within the related with the amount of phyllosilicates contained in the mete- Themis family, while the Beagle asteroids tend to be bluer, brighter, orites; the feature occurs at shorter wavelengths (near 11.4 μm) for and with less variation in their spectral slopes (Fornasier et al., more aqueously altered meteorites and longer wavelengths (near 2016). These trends are attributed to heterogeneity in the Themis 12.3 μm) for less altered meteorites. Interestingly, they found that parent body, space weathering effects, or both. Kaluna et al. (2016) the 0.7-μm absorption band, one typical diagnostic measure of the also studied visible spectra and albedos of Themis and Beagle as- presence of aqueous alteration in asteroids, did not correlate to teroids, and they, too, report that the Beagle asteroids are bluer the measured amount of phyllosilicates in the primitive meteorites. and brighter than the other Themis members, suggesting space They compared the Spitzer spectrum of (24) Themis to the mete- weathering results in the reddening and darkening of C-complex orite spectra and found it was similar to less-altered meteorites. asteroids. 2–4 μm spectroscopy of (24) Themis, the largest mem- Here, we present the results of our analysis of the mid-infrared ber of the Themis family, has revealed the presence of water Spitzer Space Telescope spectra of twenty Themis and Veritas as- ice and organics on its surface (Campins et al., 2010; Rivkin and teroids. Our sample (Table 1) consists of 9 Veritas asteroids and Emery, 2010). Recently, the signature of water ice was detected in spectra (90) Antiope, another large Themis member (Hargrove et al., 2015). Table 1 Studies of primitive asteroid families in the visible and near- Analytic proper orbital elements and taxonomic classification. infrared (NIR; 0.8 – 2.4 μm) have shown relationships between a Object Family ap (AU) ep ip (deg) Taxonomic class spectral properties and family age. Nesvorný et al. (2005) reported a trend of SDSS colors with family age for primitive asteroids, with (24) Themis Themis 3.13393 0.1525 1.0829 Cb,Cc,Bd,Ce b c d e the young Veritas asteroids at one end of the trend line and the (90) Antiope Themis 3.14543 0.1552 0.0231 C ,Ch ,C ,C (222) Lucia Themis 3.13457 0.15520 1.0486 BUb ancient Themis family at the other end. Ziffer et al. (2011) com- (223) Rosa Themis 3.08982 0.13470 1.5128 Xb,Xcc pared NIR spectra of the Themis and Veritas families. They found (316) Goberta Themis 3.17127 0.1370 1.3465 Cc that the Themis family members have red (positive) NIR slopes, (379) Huenna Themis 3.13564 0.1569 0.0307 Bb,Cd c d while the Veritas family members have blue (negative) NIR slopes. (383) Janina Themis 3.13374 0.15330 1.4096 B ,B (468) Lina Themis 3.14105 0.15970 1.2205 Xkd Observed differences between the Themis and Veritas family may (492) Gismonda Themis 3.11169 0.15220 1.2663 - be due to the large difference in the ages of the two families, com- (515) Athalia Themis 3.12074 0.15620 1.0428 Cbd positional differences, differences in thermal evolution, or a com- (526) Jena Themis 3.12237 0.15580 1.4211 Bb,Chc bination of these (Nesvorný et al., 2005; Ziffer et al., 2011). (1086) Nata Veritas 3.16534 0.06260 9.2998 Chc,Chd (2428) Kamenyar Veritas 3.16967 0.06340 9.3056 Chd We aim to investigate whether similar spectral trends exist d μ (2934) Aristophanes Veritas 3.16615 0.06230 9.1895 Ch in the mid-infrared (mid-IR; 5–14 m) by comparing spectra (3090) Tjossem Veritas 3.16909 0.06300 9.2301 Cgd for the Themis and Veritas families acquired with the Spitzer (5592) Oshima Veritas 3.16806 0.05990 9.3869 Chc Space Telescope. This wavelength range is ideally suited to study (5594) Jimmiller Veritas 3.16823 0.06040 9.3114 – both the composition and the physical properties of primitive (7231) Porco Veritas 3.16583 0.06280 9.2301 – (8726) Masamotonasu Veritas 3.17264 0.06030 9.5147 – asteroids.
Load more

Recommended publications
  • The Asteroid Veritas: an Intruder in a Family Named After It? ⇑ Patrick Michel A, , Martin Jutzi B, Derek C
    Icarus 211 (2011) 535–545 Contents lists available at ScienceDirect Icarus journal homepage: www.elsevier.com/locate/icarus The Asteroid Veritas: An intruder in a family named after it? ⇑ Patrick Michel a, , Martin Jutzi b, Derek C. Richardson c, Willy Benz d a University of Nice-Sophia Antipolis, CNRS, Observatoire de la Côte d’Azur, Cassiopée Laboratory, B.P. 4229, 06304 Nice Cedex 4, France b Earth and Planetary Sciences, University of California, 1156 High Street, Santa Cruz, CA 95064, USA c Department of Astronomy, University of Maryland, College Park, MD 20742-2421, USA d Physicalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland article info abstract Article history: The Veritas family is located in the outer main belt and is named after its apparent largest constituent, Received 19 June 2010 Asteroid (490) Veritas. The family age has been estimated by two independent studies to be quite young, Revised 19 October 2010 around 8 Myr. Therefore, current properties of the family may retain signatures of the catastrophic dis- Accepted 19 October 2010 ruption event that formed the family. In this paper, we report on our investigation of the formation of Available online 29 October 2010 the Veritas family via numerical simulations of catastrophic disruption of a 140-km-diameter parent body, which was considered to be made of either porous or non-porous material, and a projectile impact- Keywords: ing at 3 or 5 km/s with an impact angle of 0° or 45°. Not one of these simulations was able to produce Asteroids satisfactorily the estimated size distribution of real family members.
    [Show full text]
  • A Spectral Comparison of (379) Huenna and Its Satellite ⇑ Francesca E
    Icarus 212 (2011) 677–681 Contents lists available at ScienceDirect Icarus journal homepage: www.elsevier.com/locate/icarus A spectral comparison of (379) Huenna and its satellite ⇑ Francesca E. DeMeo a,b, ,1, Benoît Carry c,b,d, Franck Marchis e, Mirel Birlan f,1, Richard P. Binzel a,f, Schelte J. Bus g, Pascal Descamps f, Alin Nedelcu f,h,1, Michael Busch i, Hervé Bouy c a Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA b LESIA, Observatoire de Paris, 5 Place Jules Janssen, 92195 Meudon Principal Cedex, France c European Space Astronomy Centre, ESA, P.O. Box 78, 28691 Villanueva de la Cañada, Madrid, Spain d Université Paris 7 Denis-Diderot, 5 rue Thomas Mann, 75205 Paris Cedex, France e University of California at Berkeley, Dept. Of Astronomy, 601 Campbell Hall, Berkeley, CA 94720, USA f IMCCE, UMR8028 CNRS, Observatoire de Paris, 77 avenue Denfert-Rochereau, 75014 Paris Cedex, France g Institute for Astronomy, 640 N. Aohoku Place, Hilo, HI 96720, USA h Astronomical Institute of the Romanian Academy, 5 Cutßitul de Argint, RO-75212 Bucharest, Romania i Department of Earth and Space Sciences, University of California Los Angeles, 595 Charles Young Dr. E., Los Angeles, CA 90095, USA article info abstract Article history: We present near-infrared spectral measurements of Themis family Asteroid (379) Huenna (D 98 km) Received 17 June 2010 and its 6 km satellite using SpeX on the NASA IRTF. The companion was farther than 1.500 from the pri- Revised 2 February 2011 mary at the time of observations and was approximately 5 magnitudes dimmer.
    [Show full text]
  • Comet Hitchhiker
    Comet Hitchhiker NIAC Phase I Final Report June 30, 2015 Masahiro Ono, Marco Quadrelli, Gregory Lantoine, Paul Backes, Alejandro Lopez Ortega, H˚avard Grip, Chen-Wan Yen Jet Propulsion Laboratory, California Institute of Technology David Jewitt University of California, Los Angeles Copyright 2015. All rights reserved. Mission Concept - Pre-decisional - for Planning and Discussion Purposes Only. This research was carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration, and in part at University of California, Los Angeles. Comet Hitchhiker NASA Innovative Advanced Concepts Preface Yes, of course the Hitchhiker’s Guide to the Galaxy was in my mind when I came up with a concept of a tethered spacecraft hitching rides on small bodies, which I named Comet Hitchhiker. Well, this NASA-funded study is not exactly about traveling through the Galaxy; it is rather about exploring our own Solar System, which may sound a bit less exciting than visiting extraterrestrial civilizations, building a hyperspace bypass, or dining in the Restaurant at the End of the Universe. However, for the “primitive ape-descended life forms that have just begun exploring the universe merely a half century or so ago, our Solar System is still full of intellectually inspiring mysteries. So far the majority of manned and unmanned Solar System travelers solely depend on a fire breathing device called rocket, which is known to have terrible fuel efficiency. You might think there is no way other than using the gas-guzzler to accelerate or decelerate in an empty vacuum space.
    [Show full text]
  • A Low Density of 0.8 G Cm-3 for the Trojan Binary Asteroid 617 Patroclus
    Publisher: NPG; Journal: Nature:Nature; Article Type: Physics letter DOI: 10.1038/nature04350 A low density of 0.8 g cm−3 for the Trojan binary asteroid 617 Patroclus Franck Marchis1, Daniel Hestroffer2, Pascal Descamps2, Jérôme Berthier2, Antonin H. Bouchez3, Randall D. Campbell3, Jason C. Y. Chin3, Marcos A. van Dam3, Scott K. Hartman3, Erik M. Johansson3, Robert E. Lafon3, David Le Mignant3, Imke de Pater1, Paul J. Stomski3, Doug M. Summers3, Frederic Vachier2, Peter L. Wizinovich3 & Michael H. Wong1 1Department of Astronomy, University of California, 601 Campbell Hall, Berkeley, California 94720, USA. 2Institut de Mécanique Céleste et de Calculs des Éphémérides, UMR CNRS 8028, Observatoire de Paris, 77 Avenue Denfert-Rochereau, F-75014 Paris, France. 3W. M. Keck Observatory, 65-1120 Mamalahoa Highway, Kamuela, Hawaii 96743, USA. The Trojan population consists of two swarms of asteroids following the same orbit as Jupiter and located at the L4 and L5 stable Lagrange points of the Jupiter–Sun system (leading and following Jupiter by 60°). The asteroid 617 Patroclus is the only known binary Trojan1. The orbit of this double system was hitherto unknown. Here we report that the components, separated by 680 km, move around the system’s centre of mass, describing a roughly circular orbit. Using this orbital information, combined with thermal measurements to estimate +0.2 −3 the size of the components, we derive a very low density of 0.8 −0.1 g cm . The components of 617 Patroclus are therefore very porous or composed mostly of water ice, suggesting that they could have been formed in the outer part of the Solar System2.
    [Show full text]
  • Aqueous Alteration on Main Belt Primitive Asteroids: Results from Visible Spectroscopy1
    Aqueous alteration on main belt primitive asteroids: results from visible spectroscopy1 S. Fornasier1,2, C. Lantz1,2, M.A. Barucci1, M. Lazzarin3 1 LESIA, Observatoire de Paris, CNRS, UPMC Univ Paris 06, Univ. Paris Diderot, 5 Place J. Janssen, 92195 Meudon Pricipal Cedex, France 2 Univ. Paris Diderot, Sorbonne Paris Cit´e, 4 rue Elsa Morante, 75205 Paris Cedex 13 3 Department of Physics and Astronomy of the University of Padova, Via Marzolo 8 35131 Padova, Italy Submitted to Icarus: November 2013, accepted on 28 January 2014 e-mail: [email protected]; fax: +33145077144; phone: +33145077746 Manuscript pages: 38; Figures: 13 ; Tables: 5 Running head: Aqueous alteration on primitive asteroids Send correspondence to: Sonia Fornasier LESIA-Observatoire de Paris arXiv:1402.0175v1 [astro-ph.EP] 2 Feb 2014 Batiment 17 5, Place Jules Janssen 92195 Meudon Cedex France e-mail: [email protected] 1Based on observations carried out at the European Southern Observatory (ESO), La Silla, Chile, ESO proposals 062.S-0173 and 064.S-0205 (PI M. Lazzarin) Preprint submitted to Elsevier September 27, 2018 fax: +33145077144 phone: +33145077746 2 Aqueous alteration on main belt primitive asteroids: results from visible spectroscopy1 S. Fornasier1,2, C. Lantz1,2, M.A. Barucci1, M. Lazzarin3 Abstract This work focuses on the study of the aqueous alteration process which acted in the main belt and produced hydrated minerals on the altered asteroids. Hydrated minerals have been found mainly on Mars surface, on main belt primitive asteroids and possibly also on few TNOs. These materials have been produced by hydration of pristine anhydrous silicates during the aqueous alteration process, that, to be active, needed the presence of liquid water under low temperature conditions (below 320 K) to chemically alter the minerals.
    [Show full text]
  • IMPLICATIONS of ASTEROIDAL SATELLITES. W.J. Merline1 and C.R
    64th Annual Meteoritical Society Meeting (2001) 5457.pdf IMPLICATIONS OF ASTEROIDAL SATELLITES. W.J. Merline1 and C.R. Chapman2, 1Southwest Research Institute ([email protected]), 2Southwest Research Institute ([email protected]) There has been a recent revolution in asteroid astron- strange objects like the highly elongated metallic ob- omy that may have important implications for meteor- ject Kleopatra and the recently discovered distant sat- ite parent bodies. In short, in the last 8 years, it has ellite of a Kuiper Belt Object, could be a remnant from been found that numerous asteroids are double bodies accretionary processes. or have small satellites orbiting about them. The first one to be discovered (the 1.8 km moonlet found by the In thinking about where meteorites come from, it Galileo spacecraft to be orbiting around 31 km-sized would help parent-body modelers to have a mental Ida during a 1993 flyby) could have been a fluke, since framework that includes the kinds of configurations the accepted theoretical perspective at the time was now being discovered and the potential processes these that such satellites would be very rare or absent. How- bodies have been through before delivering meteorites ever, we now know that at least several percent of to our collections. Certainly there are implications main-belt asteroids are binaries and that a large per- from the existence of asteroidal satellites for the char- centage of Earth-approaching asteroids are binaries. acter of rubble piles, exposure ages of asteroidal rocks, and so on. The existence of double impact craters on It is not known with certainty how these satellites are the Earth and other planets may now have a more natu- created, but it is likely to be due to several different ral explanation.
    [Show full text]
  • Spectroscopic Survey of X-Type Asteroids S
    Spectroscopic Survey of X-type Asteroids S. Fornasier, B.E. Clark, E. Dotto To cite this version: S. Fornasier, B.E. Clark, E. Dotto. Spectroscopic Survey of X-type Asteroids. Icarus, Elsevier, 2011, 10.1016/j.icarus.2011.04.022. hal-00768793 HAL Id: hal-00768793 https://hal.archives-ouvertes.fr/hal-00768793 Submitted on 24 Dec 2012 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Accepted Manuscript Spectroscopic Survey of X-type Asteroids S. Fornasier, B.E. Clark, E. Dotto PII: S0019-1035(11)00157-6 DOI: 10.1016/j.icarus.2011.04.022 Reference: YICAR 9799 To appear in: Icarus Received Date: 26 December 2010 Revised Date: 22 April 2011 Accepted Date: 26 April 2011 Please cite this article as: Fornasier, S., Clark, B.E., Dotto, E., Spectroscopic Survey of X-type Asteroids, Icarus (2011), doi: 10.1016/j.icarus.2011.04.022 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form.
    [Show full text]
  • The Minor Planet Bulletin, Alan W
    THE MINOR PLANET BULLETIN OF THE MINOR PLANETS SECTION OF THE BULLETIN ASSOCIATION OF LUNAR AND PLANETARY OBSERVERS VOLUME 42, NUMBER 2, A.D. 2015 APRIL-JUNE 89. ASTEROID LIGHTCURVE ANALYSIS AT THE OAKLEY SOUTHERN SKY OBSERVATORY: 2014 SEPTEMBER Lucas Bohn, Brianna Hibbler, Gregory Stein, Richard Ditteon Rose-Hulman Institute of Technology, CM 171 5500 Wabash Avenue, Terre Haute, IN 47803, USA [email protected] (Received: 24 November) Photometric data were collected over the course of seven nights in 2014 September for eight asteroids: 1334 Lundmarka, 1904 Massevitch, 2571 Geisei, 2699 Kalinin, 3197 Weissman, 7837 Mutsumi, 14927 Satoshi, and (29769) 1999 CE28. Eight asteroids were remotely observed from the Oakley Southern Sky Observatory in New South Wales, Australia. The observations were made on 2014 September 12-14, 16-19 using a 0.50-m f/8.3 Ritchey-Chretien optical tube assembly on a Paramount ME mount and SBIG STX-16803 CCD camera, binned 3x3, with a luminance filter. Exposure times ranged from 90 to 180 sec depending on the magnitude of the target. The resulting image scale was 1.34 arcseconds per pixel. Raw images were processed in MaxIm DL 6 using twilight flats, bias, and dark frames. MPO Canopus was used to measure the processed images and produce lightcurves. In order to maximize the potential for data collection, target asteroids were selected based upon their position in the sky approximately one hour after sunset. Only asteroids with no previously published results were targeted. Lightcurves were produced for 1334 Lundmarka, 1904 Massevitch, 2571 Geisei, 3197 Weissman, and (29769) 1999 CE28.
    [Show full text]
  • The Minor Planet Bulletin
    THE MINOR PLANET BULLETIN OF THE MINOR PLANETS SECTION OF THE BULLETIN ASSOCIATION OF LUNAR AND PLANETARY OBSERVERS VOLUME 38, NUMBER 2, A.D. 2011 APRIL-JUNE 71. LIGHTCURVES OF 10452 ZUEV, (14657) 1998 YU27, AND (15700) 1987 QD Gary A. Vander Haagen Stonegate Observatory, 825 Stonegate Road Ann Arbor, MI 48103 [email protected] (Received: 28 October) Lightcurve observations and analysis revealed the following periods and amplitudes for three asteroids: 10452 Zuev, 9.724 ± 0.002 h, 0.38 ± 0.03 mag; (14657) 1998 YU27, 15.43 ± 0.03 h, 0.21 ± 0.05 mag; and (15700) 1987 QD, 9.71 ± 0.02 h, 0.16 ± 0.05 mag. Photometric data of three asteroids were collected using a 0.43- meter PlaneWave f/6.8 corrected Dall-Kirkham astrograph, a SBIG ST-10XME camera, and V-filter at Stonegate Observatory. The camera was binned 2x2 with a resulting image scale of 0.95 arc- seconds per pixel. Image exposures were 120 seconds at –15C. Candidates for analysis were selected using the MPO2011 Asteroid Viewing Guide and all photometric data were obtained and analyzed using MPO Canopus (Bdw Publishing, 2010). Published asteroid lightcurve data were reviewed in the Asteroid Lightcurve Database (LCDB; Warner et al., 2009). The magnitudes in the plots (Y-axis) are not sky (catalog) values but differentials from the average sky magnitude of the set of comparisons. The value in the Y-axis label, “alpha”, is the solar phase angle at the time of the first set of observations. All data were corrected to this phase angle using G = 0.15, unless otherwise stated.
    [Show full text]
  • The Minor Planet Bulletin
    THE MINOR PLANET BULLETIN OF THE MINOR PLANETS SECTION OF THE BULLETIN ASSOCIATION OF LUNAR AND PLANETARY OBSERVERS VOLUME 35, NUMBER 3, A.D. 2008 JULY-SEPTEMBER 95. ASTEROID LIGHTCURVE ANALYSIS AT SCT/ST-9E, or 0.35m SCT/STL-1001E. Depending on the THE PALMER DIVIDE OBSERVATORY: binning used, the scale for the images ranged from 1.2-2.5 DECEMBER 2007 – MARCH 2008 arcseconds/pixel. Exposure times were 90–240 s. Most observations were made with no filter. On occasion, e.g., when a Brian D. Warner nearly full moon was present, an R filter was used to decrease the Palmer Divide Observatory/Space Science Institute sky background noise. Guiding was used in almost all cases. 17995 Bakers Farm Rd., Colorado Springs, CO 80908 [email protected] All images were measured using MPO Canopus, which employs differential aperture photometry to determine the values used for (Received: 6 March) analysis. Period analysis was also done using MPO Canopus, which incorporates the Fourier analysis algorithm developed by Harris (1989). Lightcurves for 17 asteroids were obtained at the Palmer Divide Observatory from December 2007 to early The results are summarized in the table below, as are individual March 2008: 793 Arizona, 1092 Lilium, 2093 plots. The data and curves are presented without comment except Genichesk, 3086 Kalbaugh, 4859 Fraknoi, 5806 when warranted. Column 3 gives the full range of dates of Archieroy, 6296 Cleveland, 6310 Jankonke, 6384 observations; column 4 gives the number of data points used in the Kervin, (7283) 1989 TX15, 7560 Spudis, (7579) 1990 analysis. Column 5 gives the range of phase angles.
    [Show full text]
  • ABSTRACT Title of Dissertation: WATER in the EARLY SOLAR
    ABSTRACT Title of Dissertation: WATER IN THE EARLY SOLAR SYSTEM: INFRARED STUDIES OF AQUEOUSLY ALTERED AND MINIMALLY PROCESSED ASTEROIDS Margaret M. McAdam, Doctor of Philosophy, 2017. Dissertation directed by: Professor Jessica M. Sunshine, Department of Astronomy This thesis investigates connections between low albedo asteroids and carbonaceous chondrite meteorites using spectroscopy. Meteorites and asteroids preserve information about the early solar system including accretion processes and parent body processes active on asteroids at these early times. One process of interest is aqueous alteration. This is the chemical reaction between coaccreted water and silicates producing hydrated minerals. Some carbonaceous chondrites have experienced extensive interactions with water through this process. Since these meteorites and their parent bodies formed close to the beginning of the Solar System, these asteroids and meteorites may provide clues to the distribution, abundance and timing of water in the Solar nebula at these times. Chapter 2 of this thesis investigates the relationships between extensively aqueously altered meteorites and their visible, near and mid-infrared spectral features in a coordinated spectral-mineralogical study. Aqueous alteration is a parent body process where initially accreted anhydrous minerals are converted into hydrated minerals in the presence of coaccreted water. Using samples of meteorites with known bulk properties, it is possible to directly connect changes in mineralogy caused by aqueous alteration with spectral features. Spectral features in the mid-infrared are found to change continuously with increasing amount of hydrated minerals or degree of alteration. Building on this result, the degrees of alteration of asteroids are estimated in a survey of new asteroid data obtained from SOFIA and IRTF as well as archived the Spitzer Space Telescope data.
    [Show full text]
  • (2000) Forging Asteroid-Meteorite Relationships Through Reflectance
    Forging Asteroid-Meteorite Relationships through Reflectance Spectroscopy by Thomas H. Burbine Jr. B.S. Physics Rensselaer Polytechnic Institute, 1988 M.S. Geology and Planetary Science University of Pittsburgh, 1991 SUBMITTED TO THE DEPARTMENT OF EARTH, ATMOSPHERIC, AND PLANETARY SCIENCES IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN PLANETARY SCIENCES AT THE MASSACHUSETTS INSTITUTE OF TECHNOLOGY FEBRUARY 2000 © 2000 Massachusetts Institute of Technology. All rights reserved. Signature of Author: Department of Earth, Atmospheric, and Planetary Sciences December 30, 1999 Certified by: Richard P. Binzel Professor of Earth, Atmospheric, and Planetary Sciences Thesis Supervisor Accepted by: Ronald G. Prinn MASSACHUSES INSTMUTE Professor of Earth, Atmospheric, and Planetary Sciences Department Head JA N 0 1 2000 ARCHIVES LIBRARIES I 3 Forging Asteroid-Meteorite Relationships through Reflectance Spectroscopy by Thomas H. Burbine Jr. Submitted to the Department of Earth, Atmospheric, and Planetary Sciences on December 30, 1999 in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Planetary Sciences ABSTRACT Near-infrared spectra (-0.90 to ~1.65 microns) were obtained for 196 main-belt and near-Earth asteroids to determine plausible meteorite parent bodies. These spectra, when coupled with previously obtained visible data, allow for a better determination of asteroid mineralogies. Over half of the observed objects have estimated diameters less than 20 k-m. Many important results were obtained concerning the compositional structure of the asteroid belt. A number of small objects near asteroid 4 Vesta were found to have near-infrared spectra similar to the eucrite and howardite meteorites, which are believed to be derived from Vesta.
    [Show full text]