82 Alkmene

{{Short description|Main-belt asteroid}}

{{Use dmy dates|date=October 2019}}

{{Infobox planet

| minorplanet = yes

| background=#D6D6D6

| name=82 Alkmene

| image = 82Alkmene (Lightcurve Inversion).png

| image_scale =

| caption=A three-dimensional model of 82 Alkmene based on its light curve.

| discoverer=Karl Theodor Robert Luther

| discovered=27 November 1864

| mpc_name=(82) Alkmene

| alt_names=

| pronounced = {{IPAc-en|æ|l|k|ˈ|m|iː|n|iː}}'Alcmene, Alkmene' in The Century Dictionary and Cyclopedia (1895)

| adjective = Alkmenean {{IPAc-en|æ|l|k|ˈ|m|iː|n|i|ə|n}}Mairéad McAuley (2015), Reproducing Rome, p. 126; stress determined by verse in George Chapman, Gentleman Usher, Thomas Parrott 1907 ed., p. 220.

| named_after = Alcmene

| mp_category=Main belt

| epoch=9 December 2014 (JD 2457000.5)

| semimajor=2.7655 AU

| perihelion=2.1609 AU

| aphelion=3.3701 AU

| eccentricity=0.2186

| period=4.60 yr

| inclination=2.8286°

| asc_node=25.507°

| arg_peri=111.27°

| mean_anomaly=192.56°

| avg_speed=17.70 km/s

| dimensions={{Val|61|1.5|u=km}} (IRAS)

| mass={{Val|2.4e17|u=kg}} (assumed)

| density=

| rotation=12.999 h

| spectral_type=S

| abs_magnitude=8.40

| albedo=0.208

}}

82 Alkmene is a main-belt asteroid. Alkmene was discovered by R. Luther on 7 November 1864 and named after Alcmene, the mother of Herakles in Greek mythology. Based on IRAS data, Alkmene is estimated to be about {{convert|61|km|mi}} in diameter. A satellite has been suggested based on 1985 lightcurve data.{{Cite web|url=http://www.johnstonsarchive.net/astro/asteroidmoonsq.html|title=Other reports of asteroid/TNO companions}}

Asteroid Alkmene occulted the apparent magnitude 7.5 star HIP 99229 in the constellation of Capricornus on 18 September 2014 around 06:41 UT (17 September 23:41 PDT) and was centered on Sacramento, CA.[http://www.poyntsource.com/New/Google/20140918_32999.HTM Interactive GoogleMap of Shadow Path] {{webarchive|url=https://archive.today/20140909213828/http://www.poyntsource.com/New/Google/20140918_32999.HTM |date=2014-09-09 }}{{cite web |url=http://www.asteroidoccultation.com/2014_09/0918_82_32999.htm |url-status=dead |archive-url=https://web.archive.org/web/20140911001910/http://www.asteroidoccultation.com/2014_09/0918_82_32999.htm |archive-date=11 September 2014 |title=(82) Alkmene / HIP 99229 event on 2014 Sep 18, 06:41 UT}} Alkmene projected an eclipse shadow that moves at about {{convert|2|mi/s|km/s|order=flip|abbr=on}}. Asteroid occultations allow for accurate 2-dimensional mapping of an asteroids silhouette when observed by multiple telescopes separated by about 10 km (6.2 mi).