357 Ninina and 748 Simeisa - Two Asteroids with Earth Commensurate Rotation Periods

A global collaboration of observers from Australia, Europe, and North America found synodic rotation periods and amplitudes for 357 Ninina 35.983 ± 0.001 h, 0.11 ± 0.01 magnitudes; 748 Simeisa 11.903 ± 0.001 h, 0.08 ± 0.01 magnitudes

Lightcurve analysis of 918 itha and 2008 Konstitutsiya

Photometric studies of 918 Itha and 2008 Konstitutsiyawere made in collaboration with observers in Australia and Argentina. The large geographic longitudinal differences between the two locations helped provide aunique solution for the synodic period for both asteroids: 918 Itha, 3.47393 ± 0.00006 h; 2008 Konstitutsiya11.2692 ± 0.0004 h.Fil: Oey, Julian. Kingsgrove Observatory; AustraliaFil: Colazo, Carlos Roberto. Observatorio El Gato; ArgentinaFil: Mazzone, Fernando Dario. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Matemática; ArgentinaFil: Chapman, Andrés. Observatorio Cruz del Sur; Argentin

Lightcurve analysis of 918 itha and 2008 Konstitutsiya

Photometric studies of 918 Itha and 2008 Konstitutsiyawere made in collaboration with observers in Australia and Argentina. The large geographic longitudinal differences between the two locations helped provide aunique solution for the synodic period for both asteroids: 918 Itha, 3.47393 ± 0.00006 h; 2008 Konstitutsiya11.2692 ± 0.0004 h.Fil: Oey, Julian. Kingsgrove Observatory; AustraliaFil: Colazo, Carlos Roberto. Observatorio El Gato; ArgentinaFil: Mazzone, Fernando Dario. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Matemática; ArgentinaFil: Chapman, Andrés. Observatorio Cruz del Sur; Argentin

PERIOD DETERMINATION FOR NEA (162421) 2000 ET70

Lightcurve analysis for (162421) 2000 ET70 was performed in collaboration with observers in Uruguay, Australia, and the United States from observations obtained during the asteroid’s favorable opposition in 2012. The synodic rotation period was found to be 8.947 ± 0.001 h and the lightcurve amplitude was 0.60 ± 0.07 mag

Spin vector and shape of (6070) Rheinland and their implications

Main belt asteroids (6070) Rheinland and (54827) 2001NQ8 belong to a small population of couples of bodies which reside on very similar heliocentric orbits. Vokrouhlicky & Nesvorny (2008, AJ 136, 280) promoted a term "asteroid pairs", pointing out their common origin within the past tens to hundreds of ky. Previous attempts to reconstruct the initial configuration of Rheinland and 2001NQ8 at the time of their separation have led to the prediction that Rheinland's rotation should be retrograde. Here we report extensive photometric observations of this asteroid and use the lightcurve inversion technique to directly determine its rotation state and shape. We confirm the retrograde sense of rotation of Rheinland, with obliquity value constrained to be >= 140 deg. The ecliptic longitude of the pole position is not well constrained as yet. The asymmetric behavior of Rheinland's lightcurve reflects a sharp, near-planar edge in our convex shape representation of this asteroid. Our calibrated observations in the red filter also allow us to determine $H_R = 13.68\pm 0.05$ and $G = 0.31\pm 0.05$ values of the H-G system. With the characteristic color index $V-R = 0.49\pm 0.05$ for the S-type asteroids, we thus obtain $H = 14.17\pm 0.07$ for the absolute magnitude of (6070) Rheinland. This a significantly larger value than previously obtained from analysis of the astrometric survey observations. We next use the obliquity constraint for Rheinland to eliminate some degree of uncertainty in the past propagation of its orbit. This is because the sign of the past secular change of its semimajor axis due to the Yarkovsky effect is now constrained. Determination of the rotation state of the secondary component, asteroid (54827) 2001NQ8, is the key element in further constraining the age of the pair and its formation process.Comment: Published in AJ, 28 pages, 4 figures, 2 table

An Introduction to the Chandra Carina Complex Project

The Great Nebula in Carina provides an exceptional view into the violent massive star formation and feedback that typifies giant HII regions and starburst galaxies. We have mapped the Carina star-forming complex in X-rays, using archival Chandra data and a mosaic of 20 new 60ks pointings using the Chandra X-ray Observatory's Advanced CCD Imaging Spectrometer, as a testbed for understanding recent and ongoing star formation and to probe Carina's regions of bright diffuse X-ray emission. This study has yielded a catalog of properties of >14,000 X-ray point sources; >9800 of them have multiwavelength counterparts. Using Chandra's unsurpassed X-ray spatial resolution, we have separated these point sources from the extensive, spatially-complex diffuse emission that pervades the region; X-ray properties of this diffuse emission suggest that it traces feedback from Carina's massive stars. In this introductory paper, we motivate the survey design, describe the Chandra observations, and present some simple results, providing a foundation for the 15 papers that follow in this Special Issue and that present detailed catalogs, methods, and science results.Comment: Accepted for the ApJS Special Issue on the Chandra Carina Complex Project (CCCP), scheduled for publication in May 2011. All 16 CCCP Special Issue papers are available at http://cochise.astro.psu.edu/Carina_public/special_issue.html through 2011 at least. 43 pages; 18 figure

Arm and interarm abundance gradients in CALIFA spiral galaxies

Spiral arms are the most singular features in disc galaxies. These structures can exhibit different patterns, namely grand design and flocculent arms, with easily distinguishable characteristics. However, their origin and the mechanisms shaping them are unclear. The overall role of spirals in the chemical evolution of disc galaxies is another unsolved question. In particular, it has not been fully explored if the H ii regions of spiral arms present different properties from those located in the interarm regions. Here we analyse the radial oxygen abundance gradient of the arm and interarm star forming regions of 63 face-on spiral galaxies using CALIFA Integral Field Spectroscopy data. We focus the analysis on three characteristic parameters of the profile: slope, zero-point, and scatter. The sample is morphologically separated into flocculent versus grand design spirals and barred versus unbarred galaxies. We find subtle but statistically significant differences betweenthe arm and interarm distributions for flocculent galaxies, suggesting that the mechanisms generating the spiral structure in these galaxies may be different to those producing grand design systems, for which no significant differences are found. We also find small differences in barred galaxies, not observed in unbarred systems, hinting that bars may affect the chemical distribution of these galaxies but not strongly enough as to be reflected in the overall abundance distribution. In light of these results, we propose bars and flocculent structure as two distinct mechanisms inducing differences in the abundance distribution between arm and interarm star forming regions

6764 Kirillavrov: A Binary Asteroid

Mutual events appearing in the lightcurve of 6764 Kirrillavrov unambiguously show that it is a binary asteroid with a rotation period of 4.739 ± 0.001 h, and an orbital period of 30.41 ± 0.01 h. Follow-up observations conducted during the 2021 opposition did not detect the mutual events due to unfavorable viewing geometry. Further observations during subsequent oppositions are encouraged.Fil: Polakis, Tom. Command Module Observatory; IslandiaFil: Oey, Julian. Blue Mountains Observatory; AustraliaFil: Colazo, Milagros Rita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentin