L. l, 1 Carinae
-------------
John Pazmino
NYSkies Astronomy Inc
nyskies@nyskies.org
www.nyskies.org
2006 March 8 initial
2013 August 30 current
Introduction
-----------
On 28 February 2006 European Southern Observatory showed newly
discovered shells or envelopes around three delta Cephei stars. They
were detected by infrared interferometry at 'delta Cephei' itself,
'alpha Ursae Minoris' (Polaris), and 'L Carinae'. The astronomy and
space news media copied over these designations without comment.
I caught immediately that there is no such star 'L Carinaw'.
Perhaps this was a short form of some other name? Reading the many
accounts of the discovery turned up no explanation.
Bayer Greek letters
-----------------
In 1603 Johannes Bayerus issued his new scheme for naming stars
using small Greek letters. In general he ordered the stars by their
apparent brightness. This is a rough guide in that he followed the
Ptolemaeus order of the stars, which were more or less in brightness
order. He applied the Greek letters seriatim until he ran out. There
are 24 letters in the Greek alphabet.
To stretch the supply of letters he assigned a single letter for a
associated group of stars. Look at the pi stars of Orion, tau stars of
Eridanus, or psi stars of Auriga. He did not number the stars in the
group but merely noted there were so-many stars for the letter. The
numbering came later from other astronomers.
Later astronomers also doubled up on Greek letters for widely-
spaced double stars. They numbered the members '1' and '2', like
'gamma-1', 'gamma-2' in Virgo or 'epsilon-1', 'epsilon-2' in Lyra.
Even with grouped stars under single Greek letter, many
constellations had too many stars for the Greek alphabet. Recall that
he observed with eye alone, the telescope being a few years in the
future.He sure had good eyesight.
Bayer Latin letters
-----------------
He continued his naming with Latin letters. By chance no
constellation needed letters beyond Q, an important fact for two
centuries later.
The usual accounts state that Bayer first went thru the small
Latin letters. When these ran out, he dipped into big Latin letters.
Within these sequences later astronomers multiplexed the letters, as
shown below for L1 and L2 Puppis.
The curious fact is that in the very Uranometria, Bayer's own 1603
atlas, there are NO complete sequences of smalls and bigs. He used a
single sequence of MIXED bigs and smalls, like 'a, B, c, d, E, f, G,
...'. More over, he used different mixes for each constellation!
The use of Latin letters is a little known feature of the Bayer
system, often missed by home -- and campus! -- astronomers.
Bayer named stars in southern constellations, not visible from
northern Europe. His information about them was pretty awful, coming
from sailors and travellers inept in astronomical cartography.
The faulty information resulted in messed-up maps and star
letters. His letters were rearranged after decent mapping of the
southern skies was available.
More study of this feature of the Bayer system is needed.
Ex una, plures
------------
One of the charter 48 constellations handed to us from the Graeco-
Roman era was Argo. This in mythology is the ship that roved the sea
in hunt for the Golden Fleece. It was a large sprawling region
embedded in the southern Milky Way with lots of stars discernible to
the eye.
Bayer lettered these stars, applying a single sequence of Greek
and Latin letters. The farthest letter he needed was, ta-TAH!, 'Q' for
'Q Argus'.
When in 1930 the International Astronomical Union formalized the
constellation frontiers, it broke up Argo into four smaller groups.
They are the present Carina (keel), Puppis (stern), /Pyxis (case for
marine compass), and Vela (sails). Pyxis has only dim stars while the
other three are filled with bright ones.
However, the IAU preserved the original Bayer names from the
former humongous constellation. Hence, for all four new groups there
is ONE SEQUENCE of Bayer letters. There is, for example, we have
'alpha Carinae', former 'alpha Argus', but no 'alpha Velorum'. There
is a 'delta Velorum', former 'delta Argus', but no 'delta Puppis'.
There is a 'Q Puppis', former 'Q Argus', but no 'Q Carinae'.
Pyxis had no Bayer stars from old Argo. A whole new set was
assigned to it.
Note the nominative and genitives of the constellations. They are
a bit unusual. They are glatt Latin words, so if you have tuition in
that tongue, their orthographical shift does make sense.
+----------------------------------------------------------------+
| NAMES OF ARGO AND ITS DERIVATIVE CONSTELLATIONS |
+------------+------+--------+------------+----------------------+
| nominative | numb | declen | gentitive | Pronunciation |
+------------+------+--------+------------+----------------------+
| Argo | sing | fourth | Argus | ARR-goh, -goos |
| Carina | sing | first | Carinae | ka-REE-na, -nigh |
| Puppis | sing | third | Puppis | PUH-piss, -piss |
| Pyxis | sing | third | Pyxidis | PIKK-siss, -sih-diss |
| Vela | plur | second | Velorum | VEH-la, veh-LOH-rumm |
+------------+------+--------+------------+----------------------+
'Declen' is declension, the scheme in Latin for the spelling and
pronunciation for a noun's various grammatical functions. There are
five declensions in Latin, each with its own set of rules.
Flamsteed designations
--------------------
Johannes Flansteed in the early 1700s promulgated a new naming
scheme using only Arabic numbers. From west to east in a constellation
he numbered the stars from '1' to however many he needed. He couldn't
run out of numbers, and some constellations do have well over 100
Flamsteed stars. In Argus, still the one group back then, he numbered
only the stars he could observe from England's latitude. These all
happened to be in today's northern Puppis.
With the diffraction of Argo, there was nothing special to do with
the Flamsteed numbers except note that the star such-&-such Argus is
now such-&-such Puppis. I think the last Flamsteed star is 22 Argus,
now 22 Puppis.
For far southern constellations, with no Flamsteed numbers, we
employ Gould numbers. They resemble Flamsteed's by progressing west to
east across each constellation. They were developed by Gould in the
1870s, with generous overlap into northern constellations, as visible
from his observatory in Argentina.
Today only Flamsteed's own numbers are used in constellations
originally carrying them. Gould numbers there are abandoned. Gould's
are used only in constellations with no original Flamsteed numbers. In
the mid-south declination belt, this left some constellations with
only a few numbered stars, like Puppis.
That's how the globular cluster in Tucana is '47 Tucanae'. This is
a Gould number in that constellation, not a true Flamsteed name.
The L star
--------
In Argo there was a Bayer star L Argus. This is now L Puppis. The
reason I caught the ESO name conflict on the spot is that this L
Puppis is a well known variable star. Actually, the star is a close
line-of- sight pair. Astronomers late named it L1 and L2. L2 is the
variable. So vera mente there is no star called just 'L Puppis' but it
is short for 'L2 Puppis'. L1 has nothing of interest for it.
Because of the one suite of Bayer letters thruout the former Argo
region, there can be no star 'L Carinae'. That is historicly
impossible.
l and 1
-----
In many type styles the '1' and 'l' characters are very similar
and in a quick reading can be confused. Do you remember the typewriter?
This was a large heavy mechanical machine for stamping characters on
paper by pressing the appropriate keys on a console. There generally
was NO KEY FOR THE NUMERAL '1'! You keyed in the letter 'l' for the
numeral '1', so similar they would be if they had separate keys!!
It wasn't until the IBM electric typewriter that 'l' and '1' were
given their own keys. That was a result of the typewriter's potential
to be driven by signals from a computer, where 'l' and '1' had
distinct IBM character codes.
The l star
--------
Is that 'l' or '1'? For the Cepheid envelope case, the star name
has the small Latin letter 'l', not the Arabic numeral '1'. How to
make sure the reader knows which character is intended?
Easy! Make the 'l' a big letter 'L'. There's no way that looks
like a '1', does it? And so, in all likelihood, the authors merely
wanted to avoid mixing up the two characters and wrote the star name
with a big 'L'.
This is like using 'L' as the symbol for 'liter' rather than 'l'.
In a value-&-unit set it's too easy to read it as an extra digit '1'.
Also in all likelihood the news authors didn't realize they were
accidently duplicating the name of a whole other star -- also a
variable of substantial interest! -- in Puppis. They also probably
never thought there was a Flamsteed '1 Puppis' out there.
Note that there is BOTH a small l' and big 'L' star in the Argo
region! These are 'l Carinae' and 'L Puppis'. I don't know how this
came about since in the strict bayer system there can be only one star
with a given letter. As I noted above, more investigation is needed in
the history of the Bayer system.
1 L of an l
---------
Thus now we have a charming example of how some fellows more than
two thousand years ago who defined the constellations and two European
chaps in the 1600s and 1700s who marked letters and numbers on the
stars come to bedevil us in this 21st century.
Here are some specs for the three stars in this tangle of names
+----------------------------------------------------------------+
| THE L, l, AND 1 STARS OF ARGO AND ITS DERIVATIVES |
+-----------+--------+---------+------+----+------+------+-------+
| Star name | Rt Asc | Declin | Magn | Sp | LY | HR # | HIP # |
+-----------+--------+---------+------+----+------+------+-------+
| l Carinae | 09h45m | -62d31m | 3.7v | G5 | 1510 | 3884 | 47854 |
| L Puppis | 07h14m | -44d28m | 4.4v | M5 | 198 | 2748 | 34922 |
| 1 Puppis | 07h44m | -28d24m | 4.6 | K5 | 977 | 2993 | 32648 |
+-----------+--------+---------+------+----+------+------+-------+
The distances to the stars remain uncertain. You may find other
values elsewhere.
+-----------+---------+-------+---------+----------+
| Star name | Max-min | Days | Type | Comments |
+-----------+---------+-------+---------+----------+
| l Carinae | 3.3-4.2 | 35.53 | del Cep | = ZZ Car |
| L Puppis | 2.6-6.2 | ~140 | semireg | = L2 Pup |
| 1 Puppis | 4.6 | suspected unconfirmed var |
+-----------+---------+-------+---------+----------+
Naming variable stars
-------------------
The Bayer system of using Latin letters has an important
consequence today, even if you haven't heard of this part of his
method. When variable stars were recognized as a new celestial feature
a naming scheme for them was needed. Most of the early finds were
already named under the Bayer system" 'beta Persei, omicron Ceti, eta
Cerinae. As such no additional name was applied to them.
The first new variable in a constellation having no Bayer letter
was named 'R' in continuation of the Bayer system. We have as
examples 'R Andromedae', 'R Cancri', 'R Hydrae'. The farthest letter
needed by Bayer was 'Q', so 'R' was merely the next open letter.
Most constellations didn't have lettered stars so far in the
alphabet as 'Q'. To be consistent 'R' was always the first non-Bayer
variable star, even if this left a gap in the constellation between
its existing farthest-lettered star and 'R'. Future variables were
letters forward thru 'Z'.
Understand well that 'R' is does NOT denote the very first
variable found in a constellation. it's the first variable to receive
its own designation for lack of its own existing Bayer name..
In the 19th century when variable stars were first treated
seriously, we believed they were rare items. How many could there
possibly be in a constellation? The letters R thru Z would surely
cover all that may be found.
Wrong.
More letters
----------
When the number of variables in a constellation exceded the
alphabet thru Z, a double-letter designation was invented. I don't go
thru the details here but the first letter must be less than or equal
to the second and letter 'J' is omitted. We have 'CY Aquarii', 'SS
Cygni', 'BL Lacertae', 'RS Ophiuchi'
L2 Puppis when realized to be a variable star already had the L3
name. We left it alone without giving it a new variable star letter. l
(small Latin letter) Carinae, on the other hand, when enrolled among
the variable stars, was given the next available letter combo, This
happened to be ZZ. We got a ZZ Carinae. This was probably done to
remove the duplicate Bayer Latin letters in Argo, even tho they are
mow in different descendents of Argo.
After exhausting the possible double-letters, we gave up and went
to numbers, like 'V361 Orionis' and 'V838 Monocerotis'. Yes, there can
be hundreds of variables per constellation, specially if it's in the
Milky Way band in the sky.
It would be far better if the discovery authors used the variable
star name 'ZZ Carinae' in the stead of the mistaken 'L Carinae'. I'm
sure you saw far worse news accounts in astronomy.
Collateral history
----------------
When we delineated the frontiers of the constellations we tried to
keep the named stars of the former amorphous groups together. Once in
a while we had to let a named star fall across the border into an
other constellation, mainly because to keep in within its home
constellation would require delicate gerrymandering of the frontier.
One constraint was that variable stars must stay within the home
constellation. This comes from their names derived from the Bayer
system. A star 'UZ Lyncis' (which I picked out of the air) must stay
within the new borders of Lynx, even if the border must be stretched
to enclose it. Else it would be an orphan star in the next
constellation.
Conclusion
--------
From a news story about shells around three delta Cephei stars we
ended up exploring some interesting astronomy history. This happens
often in astronomy, that starting with one topic can expand you
inquiry into many other, at first unrelated, subjects and themes.
In some cases you'll come to deadends because the current
information is obscure or lacking. That's when you may try to build
out the missing information and then diffuse it for wider access.