ARE THESE STARS LOOKING BACK AT US?
---------------------------------
John Pazmino
NYSkies Astronomy Inc
nyskies@nyskies.org
www.nyskies.org
2008 November 18
With the ongoing discovery of planets around other stars and
increased public awareness of them, I collect here a list of the more
showy of these planetary stars. I include the entire celestial sphere,
recognizing the global residences and travels of NYSkies members.
Most of the stars hosting planets are faint and unappealing.
However, many are bright enough to see by eye under a dark sky or in
binoculars from New York. I set out here some facts and figures for
these stars. I limit them to stars with Bayer or Flamsteed names so
you can find them on binocular-level staratlases.
This article is updated iregularly to accommodate newly found
bright planetary stars and to revise the data of current ones. You can
spot new planets at the planetary stars by their year of announcement
in the last column of the table below. The latest issue of this
article is at 'www.nyskies.org/articles/pazmino/planstar.htm'.
It is still impossible for home telescopes to discern these
planets. Yet it is interesting to point out the stars themselfs to
your visitors. While these stars look entirely ordinary, they hold the
prospect that in their planets there could be people looking back at
us! NYSkies telescopists at starviewing sessions include these stars
on their roster of targets.
The columns 'star' thru 'ly' give the usual specs for the star and
are essentially fixed data. The HD number comes from the Henry Draper
catalog, a prime source for candidate planetary stars and the usual
way to reference them.
'Sun' is the apparent magnitude of Sun as seen from the star. This
is (Sun app magn) = (star app magn) - (star abs magn) + (Sun abs magn
of +4.8). As an example, the Sun seen from 51 Pegasi (the first bright
planetary star) is of apparent magnitude (5.5) - (+4.6) + (+4.8) =
5.7. The star's absolute magnitude, +4.6. is not listed in this table;
it comes from general stellar data.
'Mjup' is the planet's mass in Jupiter units. The value is (true
mass)*(sin(orbit inclination)). The planet could be far more massive.
SOme references cite mass in Earth units. Jupiter is 318 Earth masses.
'SMA' is the semimajor axis of the planet's orbit in AU. This
handles the frequent inquiry about the distance of the planet from its
star compared to Earth's distance from Sun. In general, the planets
run in strongly excentric orbits, not closely circular ones like the
planets of our solar system.
'days' is the planet's orbital period, its year, in Earth days.
'year' is when the planet was announced. This typicly is the end
of a multiyear study of the planet to establish its properties.
Following the table are comments about some of the stars.
-------------------------------------------------------------------
star HD num RA (2000) dec mag ly Sun Mjup SMA days year
------- ------ ---------------- --- --- --- ----- ----- ------ ----
54 Psc 3651 00h39.4m +21d16m 5.8 36 5.0 0.2 0.28 62.2 2003
ups And 9826 01h36.8m +41d25m 4.1 45 5.4 0.69 0.06 4.6 1996
1.89 0.83 241.5 1999
3.75 2.53 1284 1999
109 Psc 10697 01h44.9m +20d05m 6.3 91 7.4 6.12 2.13 1077.9 1999
79 Cet 16141 02h35.3m -03d34m 6.8 96 7.1 0.23 0.35 75.6 2000
81 Cet 16400 02h37.7m -03d24m 5.7 317 9.7 5.3 2.5 952.7 2008
iot Hor 17051 02h42.5m -50d48m 5.4 57 6.0 1.94 0.91 311.3 1999
94 Cet 19994 03h12.8m -01d11m 5.1 77 6.5 2 1.3 454 2000
eps Eri 22049 03h32.9m -09d27m 3.7 10 2.3 0.86 3.3 2502.1 2000
0.1 40 9999 2003
eps Ret 27442 04h16.5m -59d18m 4.4 59 6.1 1.28 1.18 423.8 2000
eps Tau 28305 04h28.6m +19h11m 3.5 155 8.2 7.6 1.93 594.9 2007
pi Men 39091 05h37.2m -80d28m 5.7 67 6.1 10.35 3.29 2064 2001
6 Lyn 45410 06h30.8m +58d10m 5.9 186 8.6 2.4 2.2 899 2008
bet Gem 62509 07h45.3m +28d02m 1.2 34 4.9 2.9 1.69 589.6 2006
pi2 UMa 73108 08h40.2m +64d20m 4.6 252 9.2 7.1 0.87 269.3 2007
rho1Cnc 75732 08h52.6m +28d20m 6.0 44 5.3 0.82 0.12 14.7 1996
0.17 0.24 44.3 2001
3.84 5.77 5218 2001
0.03 0.04 2.8 2004
0.14 0.78 260 2007
47 UMa 95128 10h59.5m +40d26m 5.0 45 5.5 2.6 2.11 1083.2 1996
0.76 3.73 2594 2003
lalaUMa 95735 11h03.4m +36d02m 7.5 8.3 1.8 0.90 --- 2118 1996
1.85 --- 9999 1996
70 Vir 117176 13h26.5m +13d37m 5.0 72 6.1 7.44 0.48 116.6 1996
tau Boo 120136 13h47.3m +17d27m 4.5 49 5.8 3.9 0.05 3.3 1996
23 Lib 134987 15h13.5m -25d19m 6.5 76 6.8 1.58 0.78 260 1999
iot Dra 137759 15h24.9m +58d58m 3.3 103 7.3 8.64 1.34 550.6 2002
kap CrB 142091 15h51.2m +35d39m 4.8 101 7.3 1.8 2.7 1191 2007
rho CrB 143761 16h01.1m +33d19m 5.4 58 6.0 1.04 0.22 39.8 1997
14 Her 145675 16h10.4m +43d49m 6.6 59 6.1 4.64 2.77 1773.4 1998
2.09 5.81 --- 2005
mu Ara 160691 17h44.1m -51d50m 5.2 50 5.7 1.67 1.5 654.5 2000
3.1 4.17 2986 2003
0.04 0.09 9.6 2004
0.52 0.92 310.6 2006
16 Cyg 186427 19h41.8m +50d31m 6.0 65 6.5 1.69 1.67 798.9 1996
xi Aql 188310 19h54.3m +08d57m 4.7 204 8.8 2.8 0.68 136.8 2008
18 Del 199665 20h58.4m +10d50m 5.5 238 9.1 10.3 2.6 993.3 2008
tau1Gru 216435 22h53.6m -48d36m 6.0 109 7.4 1.49 2.7 1442.9 2002
rho Ind 216437 22h54.6m -70d04m 6.4 86 6.9 2.1 2.7 1294 2002
51 Peg 217014 22h57.5m +20d46m 5.5 55 5.7 0.47 0.05 4.2 1995
alp PsA 216956 22h57.6m -29d37m 1.2 25 4.2 3 115 9999 2008
14 And 221345 23h31.3m +39d14m 5.2 249 9.2 4.8 0.83 185.8 2008
gam Cep 222404 23h39.3m +77d38m 3.2 38 5.5 1.6 2.04 902.9 2002
-------------------------------------------------------------------
54 Piscium is the southwestern star of the pair 54-55.
upsion Andromedae in 1999 was found to have two more planets, the
first other star with a true 'solar system'. It is sometimes misnamed
as epsilon, an altogether other star.
109 Piscium is sometimes misnamed as 106, which is nu, a wrong
star. 109 sits about one degree at 8:30 o'clock from 107 and is
easiest approached from downtown Aries.
79 Ceti is not labeled in many charts. It is about 1/2 degree west
of 81, between Mira and Caput Ceti.
81 Ceti is the brighter and eastern of the pair 79 & 81 and is
usually labeled, while 79 is not. They are only 1/2 degree apart, the
closest angular spacing between planetary stars. They are linearly
well separated, 81 Ceti being about 221LY farther away than 79.
epsilon Eridani was, with tau Ceti, the first star to be examined
in the 1960s for extraterrestrial intelligence. The second planet is
uncertain, with a period of 102,770 days, about 280 years. The value
in the table is an overflow. The inner planet rounded its periastron
during 2007, when it could have been opticly imaged. As at winter 2008
no such 'photograph' was obtained. Fomalhaut already won the honor of
having the first ever photographed planet.
epsilon Tauri is at the northern 'horn' of the Hyades. Of the
planetary stars in this table it is the only one as a member of a star
cluster.
pi Mensae has the heaviest of the known extrasolar planets in this
table, 10.35 Jupiter masses.
6 Lyncis is in an empty part of sky with few other attractions for
starviewing. It now is an interesting waypoint between Auriga and Ursa
Major.
beta Geminorum (Pollux) marks the head of the southern Twin. It is
the brightest of planetary stars, surpassing gamma Cephei. The planet
runs in a nearly circular orbit, e = 0.02, It was suspected since 1993
but confirmed in July 2006.
pi2 Ursae Majoris is 4 Ursae Majoris. It is the southeastern of a
arc of three stars: 2, pi1, pi2.
rho1 Cancri is 55 Cancri. The Bayer letters are a bit inconsistent
among authors in this part of Cancer. Look for the pair made of 53 and
55. rho1 (55) is the northeastern one of this pair. The planet found
in 2004 has semimajor axis of 0.038 AU, or 5.68 million kilometers.
The table value is rounded. rho1 in 2007 became the largest planetary
system beyond the Sun with its new 5th planet.
47 Ursae Majoris passes almost thru the zenith of New York City.
'lala' Ursae Majoris is laLande 21185, among the fastest and
closest of stars. It is 8.3 lightyears away and scoots thru 4.8 arcsec
southward each year. Its two planets are not yet verified; the
semimajor axes are still unknown. The period of the second planet is
some 30 years; the value in the table is an overflow. To find this
star you need detailed charts to at least 8th magnitude and a small
scope. Other names for this star are GSC2521-2270, HD95735, PPM75640,
SAO62377, BD+36-2147.
14 Herculis is not labeled in many charts. It is the star about
one degree at 7 o'clock from phi Herculis, with 12 at north. Its
second planet, reported in 2005, is still unconfirmed.
mu Arae has the smallest planet yet found. Altho hardly Earthlike
in character, it is only 14 times Earth's mass.
16 Cygni is occasionally mixed up with 61 Cygni, the first star
whose remoteness was certainly measured. 16 is near theta, the western
wing of the swan. 61 is near sigma & tau in the eastern wing.
xi Aquilae, also spelled ksi Aquilae, is the star 1/5 from alp Aql
(Altair) to bet Aql (Alshain).
18 Delphini is 1/2 between alp Equ and alp Del. gam and del Equ,
prolonged westward, aim almost directly at it. Its planet is the 2nd
most massive one found, after that of pi Mensae.
51 Pegasi is the first bright star, with a Bayer or Flamsteed
designation, found with a planet. Planetary stars before 51 Pegasi
were all beyond easy reach of binoculars.
alpha Piscis Austrini is Fomelhaut, with a dust disc known since
1998. The planet was found by HST imaging and is THE FIRST PLANET TO
BE OPTICLY DETECTED. It is the farthest form its star, 115 AU, and the
longest period, 872 year. '9999' in the table is an overflow. The
planet is the least luminous object ever found outside the solar
system. Fomalhaut is the second brightest planetary star, after
Pollux, so far known.
14 Andromedae is near the end of the table, which is sorted by
right ascension. It is in the western part of Andromeda, west of the
0h circle, in the 23h zone.
gamma Cephei is the third brightest planetary star so far
confirmed, after Pollux and Fomalhaut.