SELECTED SOUTHERN DOUBLES and VARIABLES
R.A. 07 Hours
HJ 3921 (07006-5824)
lies in a fairly spartan field 50.8' (PA
336°) from Δ39. This faintish
pair is listed as 8.3 and 11.5v magnitude, being
separated by 5.8 arcsec along PA
272°. Since first measured by Innes
in 1911, little has changed in the relative
positions, and from the merger data available,
it remains uncertain if the two stars are
connected. HJ 3921 is easily seen in apertures
as low as 7.5cm, but is nothing to write home
about. If it were not so easy to find to the
north of DUN 39 - I might not have even
mentioned it.
Δ38
(07040-4337) is a triple system half-way between
Sigma (σ) Puppis (Δ51) and Nu (ν)
Puppis. Unlike most Dunlop pairs, the primary
‘AB’ system is yellow and orange.
Since discovery in 1836, the pair has continued
to slowly widen by 0.8 arcsec and increased in angle
by 5°. The separation now is c.21.3 arcsec
at PA 125°, both stars being with 5.5
and 6.8 magnitude. It is likely that these two
are physically associated as they have similar
proper motions and parallaxes. Inspection of the
field finds another bright yellow star preceding
the main pair. This is the so-called
Δ38 AC and wider than most, but
since 1900, this star has reduced in separation
from 184.8 down to 136.1 arcsec (1977), changing
phenomenally by 0.63 arcsec per year! Also the PA has
changed from 334° to 282°.
I estimated the current positions as 115 arcsec at PA
250° (2001). This star is assuredly
not physically associated with the AB system. In
this case, the apparent motion is not this star,
but actually due to the double’s high
proper motion and parallax. Using the Hipparcos
data the average proper motion is -102.95 arcsec
per century (1.72' per century) in RA and
392.71 arcsec per century (6.55' per century) in
declination. This motion, however, is not the
quickest in the heavens as 61 Cyg moves almost
ten times faster. Observers might like to
compare sketches over a number of years to
physically see the motion for themselves.
Distance to Δ38 AB is 15pc or
49±2ly.
Δ39 / DUN 39
(07033-5911) is a stunningly bright southern
pair that lies in Carina, some 1.5°E
of the mid-eastern Pictor border and
8.4°NE (exactly) (PA 315°)
from the second brightest star in the sky,
Canopus. It can also be easily be found some
3.3°NW (PA 35°) from the
3.2 magnitude Alpha (α) Pictoris. The
field itself contains a yellowish 6.0 magnitude
star, some 22'NE (PA 310°) away that
has another two fainter companions (11th and
10th magnitude) in a slightly crooked line.
These latter stars will correctly identify the
field.
This is one of the very best of the Dunlop
pairs discovered from his home Parramatta in
1826. Listed also as 89 Argûs, using the
old Bode Numbering System that is similar in
nature to the Flamsteed Numbers, Dunlop gives
the magnitudes as”6,7” at 1828
co-ordinates of 07h 01m 13s and -58°
55'.
Δ39 has the naked eye combined magnitude
of 5.1 whose component magnitudes are each 5.50v
and 6.52v (5.83V and 6.78V) magnitude.
Separation is presently 1.4 arcsec along PA
86° (1997). Since discovery, the pair
continues to become a more difficult as the
separation has decrease from 2.5 to 1.4 arcsec.
I.e. Innes measured the pair from South Africa in
1912, finding the positions as 80.7°
and 1.9 arcsec. Furthermore, the PA has
continued to progressively increase from
76° to its present 86°
(1997).
Using the available Hipparchos data, which I
have assumed is correct, finds that the pair's
distance from the Sun is 147±7pc.
(481±24ly.) - calculated from the
6.77±0.34mas parallax. From this, the
true stellar separation would be around 216 AU
(3.2x1010 km.) apart,
each have respective higher luminosities than
the Sun of 118x and 46x with the absolute
magnitudes of -0.35 and +0.67.
Association of the two components is almost
certain, as the proper motions are not too
dissimilar, indicating the stars are moving
southwest toward PA 220° at some
14.84mas per year. Visually I have seen this
pair several times and each time I saw the pair
as bluish and yellowish. These observations are
contradicted by both Gould and E.J. Hartung (See
Below) who both call them yellowish. Looking at
the combined spectral class of B9IV and the B-V
of -0.125, it is hard to see how this pair could
be described as yellowish at all. Could the
colour of the other bright field star be
influencing these observers?
Δ39 Descriptions
H.J. Hartung says in AOST1&2;
”[A] 7.5cm will readily
resolve this bright pale yellow star, and the components have
shown a very slow approach and increase in angle
since John Herschel’s measures in 1836,
and common proper motion indicates they are
connected.”
Ross Gould ("Southern Astronomy";
Mar/ Apr 1994 pg.52-53) says of Δ39;
”A test for 8cm refractors, and not
difficult with 10cm ’scopes. A pale yellow
pair, of mags 6.0 and 7.1... In 1952 it was at
1.7 arcsec, PA 82°.”
RST 4340
(07091-5905) is a double star that is near
impossible to see in any amateur telescope. It
lies some 44.6'E (PA 84°) within the
next field from Δ39. For the record, this
9.4 and 10.0 magnitude very close pair was
discovered by RST 4340 is separated by
0.1 arcsec along PA 339° (1991). The
PA has continued to decreased from
73° (1940) to 339°, some
94°, thus moving from Quadrant 1 to
Quadrant 4. The primary is identified as HIP
34810, and has a parallax of 7.98±0.95
displaying significant proper motion in both RA
and Dec. Last measure in the WDS02 is the
Hipparchos one, giving the PA as 339°
and the separation as the amazingly precise
0.147±0.013 arcsec. The companion of RST
4340 is not listed in the Hipparcos Catalog but
does appear in the Tycho Catalog as T
8562:1688:1. Using these values, the distance is
125±15pc., separating the stars by some
18AU or 2.8 billion kilometres. Both these stars
must be approximately similar in mass to the
Sun, with the absolute magnitude of +3.9 and
+4.5. No doubt this is a true binary star.
What drew my attention to this object is that
the 8.9 combined magnitude deep G5V yellow
'star' is the WDS unlisted 10.3 magnitude
reddish-orange companion whose colours made this
surprising interesting visual pair. This
companion (perhaps”RST 4340 C”)
lies 42.7 arcsec away along PA 292°.
This is not listed in the HIP Catalog but is in
the Tycho Catalog, giving the magnitude as
10.34V and the significantly larger parallax of
51.80±26.20mas. This star is not likely
to be associated as the proper motion in
declination travels the wrong direction.
There are also some other colourful stars in
the same eyepiece field. First is the orange
8.35 magnitude K1III star, HIP 34618 /
SAO 234989, some 10.1'NW (PA 56°)
from RST 4340. A second orange 8.31 magnitude K1
III star is HIP 34674 / SAO 234999, which
lies either 9.6'NW (PA 33°) from HIP
34618 or 19.5'NW (PA 44°) of RST
4340. Both these stars seem unrelated even
though the colours, magnitudes and spectral
types are quite similar. To contrast these two
orange stars is another 8th magnitude blue star
8' due East of HIP 34674, which at low
powers lies on the eastern edge of the eyepiece
field if centred on RST 4340. In all, these
stars only add to an already attractive
scattered field of many faint stars.
L2 Puppis
(07135-4439) is commonly an example of a
starting variable star for new observers. Some
3°SW of the star Sigma Puppis, finds
this orangey red variable is nearly always
visible to the naked-eye. First discovered by
Gould in 1872, it type is a semi-irregular SRb
variable with the mean period that varies over
c.141.9 days while the magnitudes ranging
roughly from 3rd to 6th magnitude. It is not
unusual for it to be brighter than this maximum
on occasions. I.e. L2
Puppis has brightened once to 2.6 mag, or faded
to 6.2. Its spectrum varies from M5 to M6 and
shows unusual emission lines.
This variable is also listed bythe GVSC
classification as 071044 based on star positions
in 1900. The variable appears in the comparison
chart of RASNZ Series 1 Chart No. 8.
L2 Puppis is also the wide double
star HJ 3943 that is often missed in many common
references. The components in the WDS03 give the
5.1 and 9.5 magnitude stars a separation of
62.0 arcsec along PA 214° which was
measured in 1913. HJ 3943 B can be found using
the GSC data. This identifies for GSC 7642:279
finds the separation is presently 1.4'
(84 arcsec) along PA 221°. The GSC
gives this star 11.5V magnitude much fainter
than the given 9.5v. Another brighter 10.55V
magnitude yellow star, T 7642:1891:1 / GSC
7642:1891 (07137-4439) also appears 1.5'
(90 arcsec) away along PA 144°. From
the available data and the observed separation
this is likely just an optical pair.
[Version 2 12/11/03]
R71 AB / SLR 22 BC
(07144-4440) is a white triple star some 8.6'E
(PA 99°) of L2 Puppis. R
71 AB is the brighter of the two that contains
the 9.6 and 10.2 (9.61V and 9.77V) magnitude
stars separated by 15.9 arcsec along
PA256°. R71 suggests it has shown
some change in the positions, reducing in PA
from 288° to 256° and
18.4" to 15.9" in the last 125 years. (2004)
Russell, incidentally, gave the magnitudes as
”10,10”. R71 was discovered by H.C.
Russell just before midnight on the 1st April
1879 (1879.248) and then measured as 15.39 arcsec
along PA 77.465°. It seems that he
evaluated the brighter component incorrectly so
the position angle had 180° added to
make the new PA as 257.465 or 257.5°.
However, the WDS03 gives this 1879 separation
here as 288° and 18.4 arcsec which does not
match the Russell’s”Sydney
Observatory List of New Double Stars”
that appears written in the 1881 publication. At
the time of writing the values are being
investigated by the USNO, but it does seem that
something is quite wrong with the WDS03 figures
or that another observation was made in 1879 by
another observer preceding Russell’s own
discovery. In the earlier versions of the WDS,
the 1879 position is given as 15.2 arcsec along
PA 256° - matching Russell’s
observations. His position angle has likely been
precessed from the time of Russell’s
original measure. Another possibility is that
this is the 1935 measure and not the 1879 one,
as the older versions of the WDS state the same
scalar measures.
SLR 22 finds that the R71 B
is again double. ‘C’ is 11.2v (10.90V)
magnitude being separated by 1.7 arcsec along PA
257°. Since discovery by R.P. Sellors
at Sydney Observatory in 1896, the position
angle has reduced from 266° to
257° while the separation remains
fixed.
Common proper motions suggests that SLR 22 is
likely a true binary star but the brighter
‘A’ component is a optical
companion. All three stars form a straight line
proportioned by a ratio of about 9:1. Spectral
classes are A5, A5 and A7III, respectively. The
whole system is visible in 7.5cm and contrasts
nicely with the orange-red colour of
L2 Puppis in the field.
NEARBY PLANETARY NEBULA to R71
Sa 2-6 / Wray 17-1 /
Longmore 3 / ESO 256-19 / PK 258-15.1 / PNG
258.0-15.7 (07148-4657) is an 11.8 magnitude
PNe some 82.0 arcsecond across
that appears in the same field as I 7 -
some 46'NNW (PA 346°) away. It can be
located using L2 Puppis by moving the
telescope 2.3°S (PA 174°).
The PNe form as flat equilateral triangle with
the 5.6 magnitude orange star HIP 35181 /
SAO 218589 (07163-4646) at the apex. This star
is 18.5'NE (PA 55°) away.
Unfortunately there is another 5.7 magnitude
bluish star merely 6.4'N (PA 354°)
which interferes with the faintness of the
nebulosity.
This star is the ACV variable PR Pup (07148-4651) which
varies between 5.69V and 5.74V magnitude in the
period of 1.9347 days. (Its spectrum is A0p(Si))
Yet another star interferes with the PNe.
This second stars is the yellowish 4.5
magnitude HIP 34834 / SAO 218537
(07126-4646) that lies 26'WNW (PA
298°). It would be best to eliminate
this star from the field as the star bright will
obscure the PNe Sa2-6 itself.
HJ 3947 (07166-4614)
is a medium close pair of 8.0 and 9.9 magnitude
separated by 8.0 arcsec along PA
270°. Located 45'N (PA
348°) of I 7 or alternatively
1.7° (PA 161°) from
L2 Puppis. Little has changed since
Lawrence Hargraves first measured the pair on
the 4th April 1881. This white pair is fairly
easy in small apertures and is a good example of
a nice faintish southern pair.
I 7 (07175-4659) is
within the constellation of Puppis some
2.4°SSE (PA 163°) of the
semi-regular variable star L2 Puppis.
Innes discovered the moderately close pair in
1894 for this 6.7v and 7.9v magnitude (7.1V and
8.4V) pair being presently separated by
1.1 arcsec along PA 209° (1998) This
pair continues to decrease slowly in separation
from it original measure of 1.5 arcsec
while the PA shows retrograde motion that has
changed from 220° to today’s
209° - roughly 1° per
decade. At present the pair is visible in 15cm
using moderate to high magnification, but over
the next century the separation will continue to
become more problematic for amateur observers. I
7’s spectral class is K3III matching the
yellow-orange primary seen in the telescope.
Proper motions are similar suggesting the pair
is attached.
Δ43 / Pi (π)
Puppis (07171-3706) is easy to find as it is
the brightest star in a small triangle of stars,
some 7.4°S of Eta CMa, whose common
name is Aludra. Pi Pup is separated by 69.2 arcsec at
PA 213°, while the magnitudes are 2.7
and 8.0. Observations since 1826 has seen little
changed in the positions. I saw the colours as
deep orange and blue, making one-hell-of-a
contrast. I place this as 3rd or 4th in my Top
10 of southern contrasting, perhaps just behind
the magnificent x Velorum (Δ95)(10393-5536)
in SE Vela. This field is just remarkably memorable.
JC 10 (07183-3644) was
discovered by W.S. Jacob in 1846 appear in the
next NW field. Both these blue stars are 5.1 and
8.7 magnitude and separated by 117 arcsec at PA
216°.
R CMa / R Canis
Majoris (07195-1624) is located
8.4°W of Sirius. It can be found
1.2°S of the 9th magnitude open star cluster
NGC 2360 containing about fifty stars between
9th and 11th magnitude. This eclipsing binary is
listed as semi-detached, suggesting that it is
almost an EB system. Magnitude variations change
between 5.70 and 6.34, with the period of
1.1359405 days where the primary minima varies
by 0.64 magnitudes, while the secondary minima
dips only 0.08 magnitudes. The period’s
length is suspected to vary discontinuously.
Recent calculations place the mass of the
system as 1.20 M⊚ and 0.20 M⊚ (1989).
W. Heintz in Double Stars (1978)
states that the masses of the stars are
respectively 1.80 M⊚ and 0.2 M⊚, with
the secondary that appears very extended. It is likely that
mass transference through the Roche Lobe has
occurred in the past, and may still be
continuing, with the primary being the youngest
star. The individual luminosities are 2.8 L⊚
and 0.1 L⊚, with surface
temperatures of 6 110K and 3 110K. True distance
between the two stars, surface to surface, is
3.5 million kilometres, with the respective
individual diameters of 2 million and 1.7
million kilometres. Spectral classes are listed
as F1V and K1VI while distance is 27pc or 88 ly.
R 75 (07216-5521) is a
triple star containing a moderately faint close
pair and another wider faint component. Located
in some 8°E of Canopus, and roughly
half-way between Canopus and the open star
cluster NGC 2516 at the bottom of the false
cross, this system is a faint portion of sky
beyond the boundary of the Milky Way. Since
discovered by H.C. Russell in 1880, there has
been some motion in the main AB pair. When first
found the three stars were in a straight line,
however the movement of component
‘B’ has changed from PA
268° to PA 272° making it
slightly more bent than any straight line.
R 75 AB is the inner pair is visually
given from previous observers as 10.0 and 10.6
mag. with the Tycho values being 10.43V and
11.28V magnitude AB is separated by an unchanged
5.1 arcsec. The primary seems to be F3 III:
star.
R 75 AC is some 30.8 arcsec wide along
PA 262° yet has hardly moved since
discovery. R75 C is given as 11.47 and 10.4v
being a whole magnitude different! When I last
observed this pair in 1985, I saw all the
colours as both yellowish, however, this was a
bit harder to discern properly because of the
faint magnitude of the stars. It is possible
that the inner pair are associated, though there
is some doubt about the wider component.
Although this triple won’t set 'the world
on fire' its linear nature of the three stars is
unusual. Proper motions for the three stars are
similar, so this is likely a real system.
Pair Sep. P.A. Comp- Mag.
arcsec (o) onet (v)
R 75 AB 5.1 272 A 10.43
R 75 AC 30.8 262 B 11.28
R 75 BC 25.8 260 C 11.47
Δ47 / DAW 129
(07247-3149) is a wide yellow and white pair
just inside the southeastern Canis Major border
some 52' due west of Δ49. Both stars are
5.3 and 7.6 magnitude and are separated by 99.2 arcsec
at PA 342°, and can be seen even in
binoculars. Like Δ30, both components are
again double. The brightest component, the "AB"
system, was discovered by B.H.Dawson in 1922.
Known as DAW 129, the pair is certainly
difficult in apertures less than 25cm. At 5.3
and 11.0 magnitude, the stars and are separated
by 1.9 arcsec along PA 309°. The fainter
component in the "CD" system was discovered by
W.H. van der Bos in 1929. The "D" component is
10.8, some 3.2 mag fainter than "C", and can be
found about 1.0 arcsec along PA 205°. I
found this second pair easier to separate than
"AB", even though it is almost twice the
separation. A 20cm using medium to high
magnification should see each of the components.
The connection of the CD is likely, though the
distant pair AB-CD is presently uncertain. This
pair will challenge some observers.
Δ49
(07289-3151) this magnificent pair lies near the
southern Canis Major border. Both 6.4 and 7.2
magnitude stars are separated by 8.9 arcsec at PA
59°, and I saw both stars as blue and
blue-white. Some change has been seen with this
pair since Dunlop discovered Δ49 in 1836.
John Herschel measured the separation as
15.0 arcsec, meaning the apparent distance has
almost halved, while the position angle has
increase 4° (1993). Spectral class of
the two stars is given as B3V and B4V, with the
WDS04 giving 6.34V and 6.95V for the individual
magnitudes. The field is star-studded and the
pair is simply bedazzling!
Hartung in AOST1&2 describes the pair in
glowing terms, being;
”This bright white pair
accentuates a beautiful field sown profusely with stars, many
of which form marked curvilinear patterns. The
angle is so far fixed but the separation seems
to be diminishing slowly, and if these stars in
orbit the period must be very long.”
Looking at the proper motions the motion in
declination is A: +6″ B: +7″ per century, but
the proper motion is right ascension is nearly
double (-9 arcsec per century compared to -17 arc
seconds for the companion.) This result means
that either the orbital motion is edgewise to
the line-of-site or that the proper motions are
moving in similar directions. It is probable
that this is an optical pair but the proof will
not be known for centuries. The field also
contains a 5.7 magnitude rich blue star some
23'N Another 8.5 magnitude orange star also
appears some 14' (PA 242°) from
Δ49. [Version 2 12/11/03]
Δ51 / Sigma
(σ) Puppis (07292-4318) in my opinion
is the best in this set of double stars. Located
20°S of M93, this bright pair is of
3.2 and 8.8 mag, whose components are separated
by 22.2 arcsec along PA 74°. The pair is
quite colourful, which I see as orange and
white. Easily visible in 5cm, and little has
changed in the positions since Dunlop discovered
the pair in 1836.
COO 49 (07297-3209)
lies 20.5' (PA 151°) from Δ49.
This equal yellowish pair was discovered at the
Cordoba Observatory in 1911 and was surprisingly
missed by earlier double star observers. Listed
as 9.6 magnitude, both stars are separated by
4.5 arcsec along PA 40°. Except
for a slight 0.2″ increase in separation little
has changed. The proper motions of the two are
similar so they may be gravitationally
associated. Tycho give the deemed secondary as
the brighter star at 9.50V with the secondary
being 9.63V - though visually I could not
perceive the difference. This a nice pair that
can be seen in 10.5cm and probably with 7.5cm.
Δ50
(07294(-3149??)) the listing of Dunlop 50 has no
Declination, but Dunlop gives the star the
visual identification of 146 Argûs. An
assumed precessed position based on Δ49
are 07h 29m 26s (-31° 49'??) and this
would be 2.4'W of No. 49. However no star
appears anywhere near here.
The only clue is that the pair is separated by
2 arcsec and the magnitudes are”5 and
8” which Dunlop describes as”Very
close double star.” I looked through the
entire declinations of he constellation of
Argûs between -10° and
-60° and between 07h 20m and 07 40m
and found no candidates except RST 2482 that
match this combination of clues. (Another is HJ 3982 (See Below),
but this pair is too wide at 38.2 arcsec.)
RST 2482
(07299-2301) is 3.8° of Δ49 and
34'E of the Puppis border with Canis Major. The
pair’s position is identified simply as it
forms a flat triangle (some 39' across in RA and
10' in Declination) with the other two 5.7 and
5.9 magnitude stars to the west. Within a
moderately starry field, this surprisingly
bright and pleasant pair can be clearly
separated in 15cm using moderate magnification
but is much easier in 20cm. (127x)- with the
main problem being the sizeable Δm of 4.8
magnitudes.
It was R.T. Rossiter discovered the pair 1935,
and for something this bright it is amazing that
it was not discovered earlier. Visual magnitudes
are given as 4.9 and 10.7 whose present
separation is 3.0 arcsec along the north-south
position angle of 180°.
Unfortunately, the Hipparcos never was able to
resolve the two because of the inherent problems
of pairs in this resolution range of the
interferometric system on the satellite. This
places RST 2482 within the USNO’s
‘Neglected Southern Pairs’ list -
thus awaiting some future measures.
Since discovery, the pair has changed very
little, so attachment remains uncertain. The WDS
gives the last measure as 1967, and in 1992 I
thought I saw little with the last value.
Spectral class is given as A5Ib which partly
matches the yellowish colour reported in my
double star notes. The big question is; Was
Dunlop able to see these stars in his 9-inch
speculum mirrored telescope? Based on the
similar pairs Dunlop observed, I.e. Δ54
(3 arcsec, 6th / 9th mag.), it is just possible
this could be seen. In all I think RST 2482 is
likely Δ50.
HJ 3982 / p Pup / ADS
6205 (07354-2822) lies 2.6° (PA
70°) from η CMa. In a moderately
starry field, this lovely wide pair of 4.6 and
9.1 magnitude is separated by 38.4 arcsec along
PA 151°. HJ 3982 is easily visible in
7.5cm and is quite impressive using low
magnification in 20cm. The field also contains
an obvious yellow 7.4 magnitude star some 9'SW.
Measures have changed little since discovery and
it remains uncertain if the two are attached.
Note: This is an unlikely candidate for
Δ50. (*See Above)
HJ 4000 (07423-5840)
is a challenge for apertures around 10cm to
15cm, and easy for anything above this. Located
44'NW R79, this 7.1 and 10.2
magnitude pair is easy to find as there is
another 6.4 mag. blue star only 2.7' NNW (PA
150°). Close inspection finds that
the other star is the double that takes some
care to split. The problem is here is there is a
moderate Δm of 2.6 mag. for the 1.4 arcsec
separation. Colours are white but were uncertain
because of the faintness of the comes. HJ 4000
is showing slow direct motion from
Herschel’s angular measure in 1836 of
230° to its present 249°
but the separation has remained fixed. As the
proper motions in RA and Dec are almost fixed
but both are at least very similar, so it is
likely they are attached. Spectral Class for the
primary is A1IV. Nice.
Δ55
(07442-5027) is a bright and wide yellow /
yellowish pair in a fairly starry field that
lies in southern Puppis near the border with
Carina. It can be found 3.2°NW along
(PA 322°) from Chi (χ) Carinae or
5.2°SW (PA 231°) from the
gloriously bright multiple star Gamma (γ)
Velorum (Δ65). When Dunlop discovered this
pair, and before the grand constellation of Argo
was divided into its more manageable part, the
naked-eye star it was simply known as 209
Argûs. Given as 6.6v and 7.6v (6.64V and
7.55V) magnitude, the current position angle of
133° has changed very little since
found by Dunlop in 1826, but the separation has
slowly decreased from about 60 to 51.9 arcsec.
Spectral classes for both Main Sequence
stars are listed as F8 and G0 - corresponding
well to the observed colours. It is likely that
this pair is attached as both stars show similar
proper motion. Δ55 is highly suitable pair
even for the smallest of apertures.
NEARBY PLANETARY NEBULA to Δ55
He2-5 / Sa2-17 / ESO 209-1 / PK 264-18.1
/ PK 264-12.1 / PNG 264.4-12.7(07473-5115) is a
bright but very small planetary nebula in a
moderately spartan field within nearby Carina,
and is 55'SE (PA 145°) from the wide
pair Δ55 - useful here as the field star
to find the PNe. He2-5 is 3.0 arcsec across and
is listed as 12.3p magnitude. It is easily
visible in a 15cm especially I one is using an
O-III filter by flicking it across the field.
HJ 4002 (07451-5017)
lies in the same field as Δ55 and merely
13.4'NE (PA 40°) away. The magnitudes
are 7.5 and 11.5 with the separation being
19.5 arc seconds along PA 91°. John
Herschel when discovered the pair lists the
separation as 18.0 arcsec and the PA as
87°, but looking at the slow changes
both these values seem questionable, and likely
this reason that it was deleted in the Index of
Double Stars (IDS) in 1961. The good measures,
however, between 1913 and 1933 looks like it
changed very little, I saw the pair as yellowish
and possibly white. Knowledge of the true
attachment of the two stars is presently
unknown. This is an easy pair in 7.5cm aperture.
Δ56
(07471-4130) is 3.4° SW of ζ
Puppis and half-way between Δ51 σ
Puppis) and ζ Pup. Magnitudes are 6.9 and
7.7 for this bluish-white duo which are
separated by 49.6 arcsec along PA 177°.
These stars are certainly an optical pair, but
the field is quite nice. 7'E is a 9th mag orange
star making a nice contrast with all the blue
stars in the field. Also note the star in one of
the wide 10th mag pairs some 8'N of the main
star. This bottom star, 8'NNW of Δ56 is
the variable RR Pup (07469-4122), which
is an Algol-type eclipsing variable. The
light-curve changes between 10.34V and 11.37V
mag in the period of 6.4296338 days. Duration of
the primary eclipse is 0.83585 days.
R 79 (07472-5905) is a
wide and easy pair of 9.0 and 9.8 (8.95 and
9.84V) magnitude that was discovered by Russell
on the late evening of the 10th July 1880.
Position angle is fixed at 120°
though the 32.6 arcsec separation (1991) has
decrease from Russell's measure of 35.8 arcsec
(PA 299.8°) in 1880. According to the
WDS01, the position angle has changed from
300° to 120° between 1880
and 1991 - this might seem significant except
that the angle is out by exactly
180°. Russell’s estimated the
brightnesses as 9th and 9 1/2th quite close to
the more exact magnitudes today. R 79 lies
1.2°W of the nebulae IC 2220 being
near the centre of Carina and 4.6°W
of Epsilon (υ) Carinae / Avior. Both
stars share similar common proper motions and
are likely attached. To me this pair looks white
and yellowish in a moderately starry field. An
interesting pair to look after observing the
nebulosity of IC 2220. Another pair to look for
is HJ 4000, some 44'NW.
HJ 4018 (07522-5937)
is another triple that is fainter than HJ 4084
mentioned above that was discovered and first
measured by John Herschel in 1837. About
1.3°NNW from the centre of NGC 2516,
the triple lies within a field with two other
similar coloured stars of near equal brightness
layed out in a roughly flat triangle where HJ
4018 is the apex. HJ 4018’s white primary
star is given as 7.5 magnitude with a moderately
close 9.7 magnitude companion, joined with
another wider 11th magnitude companion. The
inner pair is HJ 4018AB, separated by
5.1 arcsec along PA 327° This is
visible in 15cm, and possibly in a well-aligned
7.5cm to 10.5cm telescope. Outer pair HJ
4018AC is much easier, as 10.91 mag. star
has the separation is 64 arcsec along PA
259°. Proper motions suggest it is
unlikely any of the stars are associated. Star
‘A’ shows it is an Ap star with
Silicon (Si) lines in its spectrum.
A nice southern pair.
Δ59
(07592-4950) lies in the far south of Puppis
near the Carina border. It can be found
3.2°SW of the multiple star Gamma
Velorum (Δ65). This pair contain two equal
blue-white stars 6.3 mag. Separated is 16.4 arcsec at
PA 47°, and little has changed since
Dunlop discovered the pair in 1836. It is
uncertain if the two stars are associated,
though I suspected the equal proper motions of
the stars makes this more than likely. The field
is densely populated with 11th and 12th mag
stars. At 11'SE is a collection of 12th
magnitude stars that look like a small open
cluster (which it is not).
The field also contains a deep red variable
star NR Pup (07596-5009) some 10'S. The
magnitude at maximum is 13.5, which is suspected
to drop below 16th. NR Pup is likely another
Mira variable but at present the period and
details of variability are not known.
“Southern Astronomical Delights”
© (2009) |
LAST UPDATED
10 Mar 2009 |
|