January 21, 2019

AstroEvent: Catch Jupiter’s Moons in 1-2-3-4 order.

Recently I’d caught something at a star party that’s worth looking out for; Jupiter’s moons in 1-2-3-4 order. This event happens 3 to 4 times a month, and is always a good teaching moment to name and explain the four Galilean moons.

The action on February 1st is best for those in the US Northeast and the Canadian Maritimes directly after sunset, and the moon Io will be the first to break the symmetry by passing behind Jupiter slightly before sunset for most US East Coast viewers westward. The table below is courtesy of astronomy calculator extraordinaire Ed Kotapish:

Dates for 2011:

(All dates and times are UT)

1-2-3-4 events for the evening apparition of Jupiter:

FEB 01 2013 TO 2258

FEB 06 0444 TO 0920

FEB 07 0943 TO 1130

FEB 27 1200 TO 1525

MAR 13 1651 TO 1930

MAR 14 1920 TO 2338

MAR 28 2310 TO MAR 29 0436

CONJUNCTION WITH SUN: April 6th, 2011.

1-2-3-4 events for the morning apparition of Jupiter:

APR 09 1126 TO 1954

APR 18 0452 TO 0541

APR 19 0510 TO 1213

APR 23 1529 TO APR 24 0348

MAY 02 0939 TO 0944

MAY 03 0914 TO 1728

MAY 14 2133 TO MAY 15 0330

MAY 29 0943 TO 1939

JUN 07 1920 TO JUN 08 1417

JUN 12 1532 TO 2329

JUN 22 0327 TO 1814

JUL 03 2316 TO JUL 04 0512

JUL 05 0618 TO 0627

JUL 13 1446 TO 1519

JUL 18 0405 TO 0900

JUL 19 0948 TO 1010

JUL 27 2149 TO JUL 28 0356

AUG 02 1337 TO 1520

AUG 11 0432 TO 0742

AUG 22 1525 TO 1832

AUG 23 1913 TO 2207

SEP 05 1941 TO 2220

SEP 06 2252 TO SEP 07 0220

SEP 21 0226 TO 0629

OCT 02 1424 TO 1549

OCT 11 0550 TO 0751

OCT 12 0741 T0 1233

OCT 16 1752 TO 2127

OCT 25 0945 TO 1141

OCT 26 1108 TO 1633

NOV 06 2314 TO NOV 07 0552

NOV 09 1944 TO 2035

NOV 15 1537 TO 1619

NOV 21 0304 TO 1138

NOV 29 1936 TO 2026

NOV 30 1952 TO DEC 01 0249

DEC 05 0654 TO 1743

DEC 13 2340 TO DEC 14 0001

DEC 14 2328 TO DEC 15 0712

DEC 26 1239 TO DEC 27 0339

The astroword for this week is Brown Dwarf. Remember that scene in the movie 2010 where the alien monoliths cause Jupiter to collapse in on itself and ignite? That level of fusion would be difficult to sustain, because Jupiter is well below the mass limit for low grade deuterium fusion to begin in the first place. Because of this, we sometimes refer to Jupiter as a “failed star,” an object not quite massive enough to enter a sub-dwarf class of stars known as brown dwarfs. At about 13 Jupiter masses deuterium fusion of hydrogen nuclei can begin and about double that, available lithium nuclei can begin to undergo the fusion process. The upper mass limit for a brown dwarf is set at about 75-80 Jupiters, and scientists are just now starting to discover examples of this class of stellar dwarf. As we get to know many of the newly discovered “hot-Jupiter” exo-planets, no doubt examples will turn up that blur the line between massive planet and proto-star… add that to the “what defines a planet” controversy!

Comments

  1. Ed Kotapish says:

    Hi Dave,

    I would think the “Royal Straight Flush” on the 1-2-3-4 would be to have the GRS visible as well!

    Ed

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