March 31 – 40 Harmonia

Main-belt asteroid 40 Harmonia was discovered by Hermann Goldschmidt on March 31st, 1856.  It is an S-type main belt asteroid, about 107 km in diameter.  One of 14 asteroids discovered by Goldschmidt, Harmonia is named after the Greek goddess of (obviously) harmony.  Her Roman counterpart was Concordia (who also has an asteroid named after her, discovered in 1860).  The name was chosen to mark the end of the Crimean War, which officially came to an end, with the signing of the Treaty of Paris, on the day before Harmonia was discovered.

Despite her harmonious attributes, the most popular stories surrounding this goddess involve a necklace she received on her wedding day, possibly from Hephaestus (different sources give various donors).  This necklace, while it apears to have had no adverse impact on Harmonia herself, had a long life bringing misery and death to all who owned it after her.

Polynices giving Eriphyle the necklace of Harmonia.

Polynices giving Eriphyle the necklace of Harmonia.

The photograph shows a red figure oinochoe (wine jug) by the Mannheim painter.   Eriphyle is being bribed by Polynices to get her husband Amphiaraüs to become embroiled in the battle of the “Seven Against Thebes”.  She was later to do the same to her son, Alcmaeon.  When he found out what she’d been up to, he killed her.


1886  –  Asteroid 254 Augusta was discovered by Austrian astronomer Johann Palisa on March 31st 1886.  It is a small main belt asteroid of about 12km diameter, and is of spectral type “S”.  It was named after Auguste von Littrow,  the widow of astronomer Carl Ludwig von Littrow.


1886  –  Asteroid 255 Oppavia is another main belt asteroid, and was also discovered on March 31st 1886 by Johann Palisa.  It’s rather larger than Augusta, at 57 km wide, and is a P-type.

The Arms of Opava

The Arms of Opava

Opava is the name of the town where Palisa was born.  It is currently in the Czech Republic, but at the time of Palisa’s birth it was part of the territory known as Austrian Silesia (following the War of Austrian Succession) which is why he is an Austrian astronomer.  Opava’s most famous daughter is Joy Adamson, author of “Born Free”.


2005  –  The large trans-Neptunian object (TNO) and Kuiper Belt object (KBO) Makemake was discovered nine years ago today.  As well as being as TNO, Makemake’s size allows it to bask in the title “dwarf planet”, and while various studies give varying opinions regarding the precise extent of that size, the prevailing view seems to be that it’s around 1,400 to 1500 km in diameter.  Unfortunately for early planet hunters, though, it’s also a very long way away,  (magnitude 16.7 at opposition) and has an unusually high orbital inclination, which is why it was only discovered so recently.

Spectral analysis of the surface suggest that up to 90% is covered in ices of methane and Nitrogen, with “tholins” also present, giving Makemake a reddish appearance visually.  It has almost no atmosphere, and (unusually for such a large TNO) no satellites.


1891  –  Discovery of asteroid 308 Polyxo by Alphonse Borrelly. Measuring 130 km across, Polyxo is one of the rare, mysterious T-type asteroids. There are multiple Polyxo’s in Greek mythology, but I believe this particular asteroid was named after one of the Hyades.


1997  –  Death of Lyman Strong Spitzer Jr.


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March 29 – 4 Vesta

Asteroid 4 Vesta, the brightest asteroid visible from Earth, and one of the larger, at about 530 km wide, was first spotted on March 29th 1807 by Heinrich Wilhelm Olbers. It is named after the Roman goddess of the home and hearth, who always had a fire burning in her temples as a reminder.  Vesta is the second most massive asteroid (after Ceres, which had been discovered the year before)  but is only the third biggest by volume (Pallas, also discovered by Olbers, five years earlier, takes second place).

Composite image of Vesta from the DAWN spacecraft (image credit: NASA)

Composite image of Vesta from the DAWN spacecraft (image credit: NASA)

Vesta was visited recently (July 2011) by NASA’s Dawn spacecraft, which took the above image (actually it’s a collection of many images stuck together). Observations show it to be an oblate spheroid, but irregularities in shape and the low mass mean it doesn’t qualify as a dwarf planet under the current naming rules.


 2002  –  Launch of the Reuvan Ramaty High Energy Solar Spectroscopic Imager (HESSI, or RHESSI) to study solar flares.


March 28 – 2 Pallas

Asteroid 2 Pallas was discovered on March 28th, 1802, by Heinrich Wilhelm Olbers, physician by day, astronomer by night, and the man after whom the Olbers Paradox (the one about why the sky is dark if the universe is infinite) is named.  He discovered Pallas while trying to locate Ceres, which had been discovered by Giuseppe Piazzi the previous year.

Pallas (from the Hubble Space Telescope). Image: NSAS

Pallas (from the Hubble Space Telescope). Image: NASA

Pallas is at the larger end of the minor planet scale,  being about 550 km wide on average (it isn’t round). It is a B-type body, one of the less common asteroid types. B’s are similar to the much more populous C-types, but with a greater albedo, and different a absorption lines in their spectra.

Statue of Pallas Athene above the Austrian Parliament Building in Vienna (image credit: Max Novara)

Statue of Pallas Athene above the Austrian Parliament Building in Vienna (image credit: Max Novara)

Pallas is named after the Greek goddess Athena (she was often referred to as Pallas Athena/Athene), goddess of wisdom, daughter of Zeus and Metis, owner of the Aegis, and friend of owls. Her Roman equivalent was Minerva.


On March 28, 1900, asteroid 454 Mathesis was discovered from Heidelberg by Friedrich Karl Arnold Schwassmann. Mathesis is a main belt asteroid of about 81.6 km diameter, having, apparently, a rather pleasing year of 1555.5 days, and an equally pleasing albedo of 0.0555. I wonder if that’s why it was named after mathematics?

Schwassmann was discoverer of 22 asteroids, but this was his first without the assistance of the even more prolific discoverer, Max Wolf .


 2009  –  Start of ISS expedition 19.


March 27 – M101

Messier 101, also known as the Pinwheel Galaxy (NGC 5457) in Ursa Major, was discovered on March 27, 1781, by Pierre Méchain.  It is more than 20 million light years distant, contains around 1 trillion stars, and measures approximately 170,000 light years across (probably quite similar to the Milky Way, although our galaxy is hard to measure from the inside).

M101 (Image credit: ESA / NASA, Davide De Martin, and K.D. Kuntz)

M101 (Image credit: ESA / NASA, Davide De Martin, and K.D. Kuntz)

M101 has its own group of galaxies (called the M101 Group, obviously), and is one of a collection of groups of galaxies (including our own Local Group) that make up the Virgo Supercluster, a vast conglomeration of more than 100 groups of galaxies.


1886  –  Spiral galaxy NGC 2981, in the constellation of Leo, was discovered by Samuel Oppenheim (or possibly Johann Palisa – there is a little uncertainty).


1886  –  Barred Spiral galaxy NGC 2926 and spiral galaxy NGC 2944 (both in the constellation Leo Minor) were discovered by Johann Palisa.  These two are listed separately from the above NGC 2981 because they are definitely Palisa’s.


1906  –  Discovery of asteroid 594 Mirielle by Max Wolf at Heidelberg. It was named after a poem by the French poet Frédéric Mistral.  In the poem, written in the Occitan language, Mirèio is a farmer’s daughter who runs away from home to escape her father’s poor choice of suitors for her.


1964  –  Launch of Kosmos 27 on a planned trip to study the hostile Venusian atmosphere (when it would probably have been known as Zond 3MV-1 No 3). Unfortunately, an upper stage malfunction resulted in a mission duration of approximately one day, and a fiery death in Earth’s atmosphere.


1968  –  Death of Yuri Gagarin, hero of the Soviet Union, aged 34.
image


 

 

March 26 – Explorer 3

Explorer 3 was launched on March 26th 1958 from Cape Canaveral, using a Juno I four stage launcher, the same rocket that had been used to launch (successfully) Explorer 1 and (less than successfully) Explorer 2.

Explorer 3 (probably)

Explorer 3 (probably)

Explorer 3 looked almost exactly like Explorer 1, hence the non-committal title of the above photograph, and had the same task, to explore the Earth’s radiation belts.  Those whip-like things sticking out from the body are transmitting antennae, kept extended by the rotation of the satellite.


Asteroid 561 Ingwelde discovered by Max Wolf in 1905. The prevailing view seems to be that Ingwelde was named after the opera by Max von Schillings. I’m inclined to agree, as the opera had been doing the rounds in the years leading up to 1905. Following its premiere in Karlsruhe (1894) it had been revived in Munich in 1896, directed by no less a person than Richard Strauss (albeit for only three performances).


March 25 – Titan

Titan, Saturn’s largest moon, and the second largest moon in the Solar System (behind Ganymede, which is only ever so slightly bigger), was discovered on March 25th 1655 by the Dutch astronomer Christiaan Huygens.  As the first moon to be discovered around Saturn there was no immediate pressure on Huygens to find an impressive name for it, so he settled for Luna Saturni (Saturn’s moon).  It wasn’t until Cassini discovered a further four Saturnian moons that a naming system became an issue, and even then the solution wasn’t particularly imaginative (“Saturn IV” to start off with, then “Saturn VI” after a couple more were found).  It was John Herschellson of the more famous William, who came up with the name Titan, as well as the names of the other six saturnian moons known at the time.

Titan, with Tethys in the background (image: NASA)

Titan, with Tethys in the background (image: NASA)

Titan, as you can see from the picture below, is shy, and doesn’t like to show us a great deal of surface detail.  It is the only moon in the Solar System with a substantial atmosphere, so dense in fact that the surface pressure is about half as great again as on Earth.  It is also suspected of having the potential to support microbial life, making it a very tempting place for Earthlings to visit.

Titan from the Cassini Spacecraft (false colour image in Ultraviolet and Infrared). Image credit: NASA / JPL / Space Science Institute.

Titan from the Cassini Spacecraft (false colour image in Ultraviolet and Infrared). Image credit: NASA / JPL / Space Science Institute.

In the hierarchy of Saturnian moons, Titan is right at the top of the pile.  It has a mass of 1.34 x 1023 kg (that’s about twice the mass of our own lightweight moon) which makes it far and away the biggest, accounting for 96% of the combined mass of all Saturn’s satellites.


1928  –  Jim Lovell (commander of Apollo 13) born today in Cleveland, Ohio. Captain James Lovell, USN, is a veteran of four space flights (he was the first man to achieve the feat) totalling 29 days: Gemini 7, Gemini 12, Apollo 8, and Apollo 13. He is also the only person to fly to the Moon twice without landing on it.


March 24 – Concordia

On March 24 1860 Karl Theodor Robert Luther discovered the C-type asteroid 58 Concordia from the Düsseldorf-Bilk Observatory.  As you may remember (I mention it every so often) Luther discovered 24 asteroids in all.  This one was named after the Roman goddess of marital harmony and understanding.  The name was chosen by Karl Christian Bruhns, the recently appointed professor of astronomy at the University of Leipzig.

Concordia (image credit: Andreas Praefcke)

Concordia (image credit: Andreas Praefcke)

Concordia is a main belt asteroid, 90-odd km wide, orbiting at between 2.5 and 2.8 AU, and taking 4.44 years to orbit the Sun.  It is a member of the Nemsis family, a medium-sized asteroid family with about 250 known members, predominantly C-types.


1781   –   Messier 105 (NGC 3379).  If you think back a couple of days you might remember me mentioning a group of galaxies in Leo containing M95 and M96, both of which were discovered on March 20th 1781.  M105 is also in the group, and it was discovered on March 24th 1781, also by Messier’s assistant Pierre Méchain, who was on a roll.  Unlike the other two, this one is an elliptical galaxy, and is known to have a supermassive black hole at its centre.

M105 (image credit: NASA)

M105 (image credit: NASA)

M105 is the brightest elliptical galaxy in this particular group.  It is an E1 type, and is approximately 38 million light years away from Earth.  The “E” rating for galaxies is based on their elongation, where “E0” is fairly round, while “E7” is extremely stretchy.  E1 galaxies are only slightly elongated.


March 22 – Messier 94

Messier 94, also known as NGC4736, was discovered today in 1781 by Pierre Méchain. It is a spiral galaxy in the constellation Canes Venatici, and is about 16 million light years (4.91 megaparsecs) away from us.

M94 (Image: NASA; JPL; Spitzer)

M94 (Image: NASA; JPL; Spitzer)

M94 has its own grouping of galaxies within the Virgo Supercluster, called (unsurprisingly) the M94 group . The group has about 20 members.


Asteroid 327 Columbia was discovered by Auguste Charlois on March 22nd, 1892. It is in the main belt, has an absolute magnitude of 10.1, and is of unknown spectral type.

Asteroid 327 was named after Christopher Columbus, the Genes explorer who helped kick-start the Spanish colonisation of the Americas.  Any mental image you might have of Columbus’ appearance is from a portrait made after his death.  There are no known paintings of Columbus dating from his lifetime.  So I won’t be including one here.


 

March 20 – Messier Triple Bill

Messier 93, NGC2447, was discovered on this day in 1781. This binocular object is an open cluster about 3,600 light years away, spanning approximately 10 light years, in the constellation Puppis. It was the last open cluster to be discovered by Charles Messier himself. M93 contains a good collection of blue giant stars, as well as quite a few red giants, possibly in clusters of their own. It’s hard to say how many stars a cluster contains, mainly because they get in each other’s way when you try to count them. This one has at least 80 identifiable members, but may well turn out to be several hundred strong.

M93

M93

Messier 95 is a great example of a barred spiral with a “circumnuclear ring”. It, too, was discovered on March 21st 1781, and is a member of the Leo I group of galaxies.

M95

M95

The final member of today’s triple bill is Messier 96. It was identified by Messier’s assistant Pierre Méchain, and is the largest member of the Leo I group. Unlike M95 it has an asymmetrical structure and an off-centre nucleus, the result of gravitational interractions with other members of the group.

M96

M96

 

The Leo I group also contains M101, and they are located about 35 to 40 million light years away. All three should show up as grey fuzzy patches in small telescopes, given suitable viewing conditions.


March 18 – 136 Austria

Asteroid 136 Austria was discovered on March 18th 1874 by Austrian astronomer Johann Palisa.  Being his first discovery, he got a bit patriotic when it came to choosing a name, although he did stick to the convention of Latinising the name, rather than use Österreich or Oesterreich.

The Coat of Arms of Austria

The Coat of Arms of Austria

136 Austria is in the main belt, is about 40 km wide, and may or may not be an M-type.  A study by Clarke et al published in the Abstracts of the 25th Lunar and Planetary Science Conference suggest it may be more of an S-type.