_Ernestina.png) Modelled shape ofErnestina from itslightcurve | |
| Discovery[1] | |
|---|---|
| Discovered by | J. Helffrich |
| Discovery site | Heidelberg Obs. |
| Discovery date | 5 March 1910 |
| Designations | |
| (698) Ernestina | |
Named after | Ernst Wolf (son ofMax Wolf)[2] |
| A910 ED · A908 WB 1910 JX | |
| main-belt[1][3] · (outer)[4] background[5][6][7] | |
| Orbital characteristics[3] | |
| Epoch 31 May 2020 (JD 2459000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 111.16yr (40,601 d) |
| Aphelion | 3.1847AU |
| Perihelion | 2.5490 AU |
| 2.8669 AU | |
| Eccentricity | 0.1109 |
| 4.85 yr (1,773 d) | |
| 269.92° | |
| 0° 12m 10.8s / day | |
| Inclination | 11.532° |
| 40.630° | |
| 98.687° | |
| Physical characteristics | |
| 5.0363±0.0005 h[11] | |
698 Ernestina (prov. designation:A910 EDor1910 JX) is abackground asteroid, approximately 27 kilometers (17 miles) in diameter, located in the outer regions of theasteroid belt. It was discovered on 5 March 1910, by German astronomerJoseph Helffrich at theHeidelberg-Königstuhl State Observatory.[1] The presumed carbonaceousC-type asteroid has arotation period of 5.0 hours. It was named after Ernst Wolf, son of German astronomer and prolificdiscoverer of minor planets,Max Wolf.[2]
Ernestina is a non-family asteroid of the main belt'sbackground population when applying thehierarchical clustering method to itsproper orbital elements.[5][6][7] It orbits the Sun in theouter asteroid belt at a distance of 2.5–3.2 AU once every 4 years and 10 months (1,773 days;semi-major axis of 2.87 AU). Its orbit has aneccentricity of 0.11 and aninclination of 12° with respect to theecliptic.[3] The asteroid was first observed as1908 WB atHeidelberg Observatory on 28 November 1908. The body'sobservation arc begins with its official discovery observation on 5 March 1910.[1]
Thisminor planet was named after Ernst Wolf, son of German astronomerMax Wolf (1863–1932), who has discovered many asteroids at Heidelberg including some of the firstnear-Earth objects andJupiter trojans. Thenaming citation was mentioned inThe Names of the Minor Planets byPaul Herget in 1955 (H 71).[2]
Ernestina is an assumed carbonaceousC-type asteroid.[4] In a taxonomic classification based on MOVIS near-infrared colors, the asteroid's preliminary determined Cgx-type was ultimately rejected and its final class changed to "undefined" (U). MOVIS data has been obtained by theVISTA Hemisphere Survey using theVISTA telescope atParanal Observatory in Chile.[13]
In October 2005, a rotationallightcurve ofErnestina was obtained fromphotometric observations by an international collaboration led byDonald Pray at Carbuncle Hill Observatory (912). Lightcurve analysis gave a well-definedrotation period of5.0363±0.0005 hours with a brightness variation of0.30±0.02magnitude (U=3).[11] Alternative period determinations in ascending order include:5.00±0.05 h by Gordana Apostolovska in 2011 (U=2),[4]5.03654±0.00004 h byLaurent Bernasconi in 2002 (U=3),[14]5.037±0.0008 h by astronomers at thePalomar Transient Factory in 2010 (U=2),[15]5.0415±0.0006 h byRené Roy in 2017 (U=3),[14]5.0431±0.0002 h byDavid Polishook in 2005 (U=3),[16] and5.07 h byVioleta Ivanova in 2002 (U=3).[17]
Two lightcurves, published in 2016, using modeled photometric data from the Lowell Photometric Database (LPD) and other sources, gave a concurring sidereal period of (5.03660±0.00005) and (5.03661±0.00001) hours, respectively. Each modeled lightcurve also determined twospin axes of (213.0°, −66.0°) and (76.0°, −49.0°), as well as (282.0°, −79.0°) and (114.0°, −45.0°) inecliptic coordinates (λ, β), respectively.[12][18]
According to the surveys carried out by the JapaneseAkari satellite, the Infrared Astronomical SatelliteIRAS and theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer (WISE),Ernestina measures (26.74±0.63), (27.03±1.2) and (29.804±0.438) kilometers in diameter and its surface has analbedo of (0.130±0.007), (0.1269±0.012) and (0.095±0.016), respectively.[8][9][10] TheCollaborative Asteroid Lightcurve Link derives an albedo of 0.1064 and a diameter of 26.92 kilometers based on anabsolute magnitude of 10.9.[4] The WISE team also published an alternative mean-diameter (27.037±0.242 km) and an albedo of (0.116±0.022).[6]
