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List of stars in Libra
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This is the list of notable stars in the constellation Libra, sorted by decreasing brightness.

Name B F Var HD HIP RA Dec vis.
mag. 		abs.
mag. 		Dist. (ly) Sp. class Notes
β Lib β 27 135742 74785 15h 17m 00.47s −09° 22′ 58.3″ 2.61 −0.84 160 B8V Zubeneschamali; suspected variable
α2 Lib α2 9 130841 72622 14h 50m 52.78s −16° 02′ 29.8″ 2.75 0.88 77 A3IV Zubenelgenubi; spectroscopic binary; suspected variable; member of the α Lib system
σ Lib σ 20 133216 73714 15h 04m 04.26s −25° 16′ 54.7″ 3.25 −1.51 292 M3/M4III previously γ Scorpii, Brachium; semiregular variable, Vmax = 3.2m, Vmin = 3.46m, P = 20 d
υ Lib υ 39 139063 76470 15h 37m 01.46s −28° 08′ 06.3″ 3.60 −0.28 195 K3III previously o Scorpii
τ Lib τ 40 139365 76600 15h 38m 39.38s −29° 46′ 39.7″ 3.66 −2.01 445 B2.5V
γ Lib γ 38 138905 76333 15h 35m 31.54s −14° 47′ 22.4″ 3.91 0.56 152 K0III Zubenelhakrabi, has two planets
θ Lib θ 46 142198 77853 15h 53m 49.48s −16° 43′ 46.6″ 4.13 0.64 163 K0III
16 Lib 16 132052 73165 14h 57m 11.06s −04° 20′ 45.9″ 4.47 2.24 91 F0V
ι1 Lib ι1 24 134759 74392 15h 12m 13.31s −19° 47′ 29.9″ 4.54 −0.77 376 Asp... α2 CVn variable, Vmax = 4.53m, Vmin = 4.56m, P = 3.10 d
37 Lib 37 138716 76219 15h 34m 10.52s −10° 03′ 50.3″ 4.61 2.30 94 K1IV
κ Lib κ 43 139997 76880 15h 41m 56.82s −19° 40′ 42.9″ 4.75 −0.69 400 K5III Rì (日),[1] suspected variable
δ Lib δ 19 132742 73473 15h 00m 58.39s −08° 31′ 08.2″ 4.91 0.06 304 B9.5V Zuben Elakribi or Mululizu; Algol variable, Vmax = 4.91m, Vmin = 5.9m, P = 2.33 d
ε Lib ε 31 137052 75379 15h 24m 11.93s −10° 19′ 18.8″ 4.92 2.37 106 F5IV
11 Lib 11 130952 72631 14h 51m 01.02s −02° 17′ 55.9″ 4.93 0.82 216 G8... RS CVn variable, Vmax = 4.91m, Vmin = 4.95m, P = 60.55 d
48 Lib 48 FX 142983 78207 15h 58m 11.38s −14° 16′ 45.5″ 4.95 −1.03 513 B8Ia/Iab γ Cas variable, Vmax = 4.74m, Vmin = 4.96m
42 Lib 42 139663 76742 15h 40m 16.91s −23° 49′ 05.0″ 4.97 −0.37 381 K3III suspected variable
λ Lib λ 45 142096 77811 15h 53m 20.06s −20° 10′ 01.2″ 5.03 −0.16 356 B3V α2 CVn variable, ΔV = 0.02m, P = 3.31 d[dubious – discuss]
36 Lib 36 138688 76259 15h 34m 37.31s −28° 02′ 48.9″ 5.13 −0.14 369 K2/K3III
α1 Lib α1 8 130819 72603 14h 50m 41.26s −15° 59′ 49.5″ 5.15 3.28 77 F3V spectroscopic binary; member of the α Lib system
HR 5780 IU 138764 76243 15h 34m 26.53s −09° 11′ 00.1″ 5.16 0.00 351 B6IV slowly pulsating B star, Vmax = 5.14m, Vmin = 5.19m, P = 1.26 d
ν Lib ν 21 133774 73945 15h 06m 37.62s −16° 15′ 24.3″ 5.19 −1.66 765 K5III Zuben Hakrabim
12 Lib 12 131430 72929 14h 54m 20.14s −24° 38′ 31.7″ 5.27 −0.09 384 K2/K3III
μ Lib μ 7 130559 72489 14h 49m 19.09s −14° 08′ 56.3″ 5.32 1.03 235 Ap α2 CVn variable
HD 126218 126218 70469 14h 24m 48.66s −24° 48′ 22.6″ 5.34 −0.10 400 K0III
41 Lib 41 139446 76628 15h 38m 54.51s −19° 18′ 06.2″ 5.36 0.27 340 G8III/IV
η Lib η 44 140417 77060 15h 44m 04.42s −15° 40′ 21.6″ 5.41 2.14 147 A6IV Zuben Hakrabi
49 Lib 49 143333 78400 16h 00m 19.98s −16° 31′ 56.6″ 5.47 2.89 107 F7V variable star, ΔV = 0.004m, P = 0.45 d
ξ2 Lib ξ2 15 131918 73133 14h 56m 46.11s −11° 24′ 35.0″ 5.48 −0.61 538 K4III
HD 138413 138413 76106 15h 32m 36.71s −19° 40′ 13.3″ 5.50 1.29 227 A2IV
HD 132833 132833 73497 15h 01m 19.81s −02° 45′ 17.5″ 5.52 −0.67 564 M0III suspected variable
HD 135534 135534 74732 15h 16m 23.03s −22° 23′ 57.9″ 5.52 −0.41 500 K2III
ζ4 Lib ζ4 35 138485 76126 15h 32m 55.23s −16° 51′ 10.1″ 5.53 −1.33 769 B3V suspected variable
30 Ser (30) 141378 77464 15h 48m 56.81s −03° 49′ 06.7″ 5.53 2.07 160 A5IV
50 Lib 50 143459 78436 16h 00m 47.64s −08° 24′ 40.8″ 5.53 −0.21 459 A0Vs
HD 136479 136479 75127 15h 21m 07.64s −05° 49′ 29.4″ 5.54 0.96 269 K1III
ζ1 Lib ζ1 32 137744 75730 15h 28m 15.40s −16° 42′ 59.1″ 5.64 −1.58 908 K4III On 24 December 2031 it will be occulted by Venus over the North Pacific, Alaska, Northern Canada.[2]: 165 
HD 130529 130529 72488 14h 49m 18.76s −24° 15′ 05.3″ 5.68 −1.99 1113 K3III+...
4 Lib 4 129433 71974 14h 43m 13.57s −24° 59′ 51.8″ 5.70 0.21 409 B9.5V 53 Hydrae
Gliese 570 KX 131977 73184 14h 57m 27.35s −21° 24′ 55.7″ 5.72 6.86 19 K4V BY Dra variable, ΔV = 0.04m
HD 136956 136956 75352 15h 23m 52.26s −12° 22′ 09.9″ 5.72 −0.61 603 G8III
HD 134373 134373 74239 15h 10m 18.65s −26° 19′ 57.4″ 5.75 0.05 450 K0III
ξ1 Lib ξ1 13 131530 72934 14h 54m 22.91s −11° 53′ 54.0″ 5.78 0.54 365 G7III
HD 139254 139254 76532 15h 37m 48.06s −23° 08′ 29.5″ 5.79 1.18 272 K0III
HD 129944 129944 72210 14h 46m 06.75s −23° 09′ 10.3″ 5.80 0.55 366 K0III
ζ3 Lib ζ3 34 138137 75944 15h 30m 40.39s −16° 36′ 34.0″ 5.82 −0.37 564 K0III
HD 139329 139329 76569 15h 38m 16.24s −21° 00′ 58.2″ 5.82 1.06 292 K0III
HD 135051 135051 74539 15h 13m 53.32s −26° 11′ 36.8″ 5.84 −1.41 918 G8/K0II
18 Lib 18 132345 73310 14h 58m 53.64s −11° 08′ 37.9″ 5.88 0.95 316 K3III-IV
47 Lib 47 142378 77939 15h 55m 00.37s −19° 22′ 58.4″ 5.95 −0.46 623 B2/B3V suspected variable
HD 130157 130157 72310 14h 47m 13.66s −21° 19′ 29.6″ 6.05 −2.73 1863 K4/K5III
ι2 Lib ι2 25 134967 74493 15h 13m 19.22s −19° 38′ 50.8″ 6.07 1.93 219 A2V
HD 132375 132375 73309 14h 58m 52.99s −04° 59′ 20.4″ 6.08 3.37 114 F8V
HD 142703 HR 142703 78078 15h 56m 33.33s −14° 49′ 45.7″ 6.12 2.48 173 A2Ib/II δ Sct variable, ΔV = 0.02m, P = 0.06 d
HD 133670 133670 73927 15h 06m 27.10s −22° 01′ 54.1″ 6.13 2.24 195 K0III suspected variable
ο Lib ο 29 136407 75118 15h 21m 01.36s −15° 32′ 54.2″ 6.14 2.45 178 F2V
HD 130557 130557 72449 14h 48m 54.10s −00° 50′ 51.7″ 6.15 0.98 353 B9Vsvar...
28 Lib 28 136366 75110 15h 20m 53.68s −18° 09′ 30.6″ 6.16 −0.27 631 G8II/III
26 Lib 26 135230 74600 15h 14m 33.77s −17° 46′ 06.7″ 6.18 −1.80 1283 B9III
HD 139160 139160 76503 15h 37m 28.51s −26° 16′ 47.3″ 6.19 −0.14 600 B9IV
HD 128429 128429 71469 14h 36m 59.80s −12° 18′ 19.1″ 6.20 3.66 88 F6V + WD Blue straggler
HD 138105 138105 75939 15h 30m 36.25s −20° 43′ 42.5″ 6.20 1.92 234 A3V suspected variable
HD 141853 141853 77689 15h 51m 38.41s −14° 08′ 00.8″ 6.20 −0.43 692 G8III
2 Lib 2 126035 70336 14h 23m 25.63s −11° 42′ 50.0″ 6.22 1.19 330 G7III
HD 140986 140986 77287 15h 46m 45.43s −06° 07′ 13.3″ 6.24 −1.05 937 K0III
HD 138488 138488 76143 15h 33m 09.53s −24° 29′ 25.2″ 6.26 1.22 331 A3/5V +A9/F2
10 Lib 10 131027 72702 14h 51m 51.31s −18° 21′ 19.2″ 6.27 −0.97 913 K0II/III
HD 135367 135367 74623 15h 14m 50.61s −05° 30′ 09.3″ 6.28 −0.95 911 K3III
HD 138268 138268 76033 15h 31m 43.45s −20° 09′ 53.4″ 6.28 1.96 239 A5V
HD 140301 140301 77007 15h 43m 24.86s −15° 02′ 34.8″ 6.30 0.80 411 K0III
HD 139290 139290 76567 15h 38m 15.80s −28° 12′ 23.8″ 6.32 0.14 562 K1III
HD 142640 142640 78059 15h 56m 14.41s −14° 23′ 57.2″ 6.32 2.29 208 F6V
5 Lib 5 129978 72194 14h 45m 57.78s −15° 27′ 34.4″ 6.33 −1.33 1109 K2III
HD 139518 139518 76666 15h 39m 21.39s −23° 09′ 00.6″ 6.33 1.47 306 B9.5V
HD 130325 130325 72373 14h 47m 54.92s −12° 50′ 23.2″ 6.34 1.12 361 K0III
HD 132953 132953 73571 15h 02m 08.59s −07° 34′ 31.1″ 6.38 0.13 580 A5V
22 Lib 22 133800 73953 15h 06m 49.10s −16° 29′ 03.6″ 6.41 0.90 413 A1V
HD 129980 129980 72217 14h 46m 10.92s −21° 10′ 32.6″ 6.43 3.30 138 G2V
HD 137798 137798 75790 15h 28m 58.69s −28° 52′ 00.5″ 6.43 2.51 198 G0V
23 Lib 23 134987 74500 15h 13m 28.93s −25° 18′ 33.0″ 6.45 4.40 84 G5V has two planets (b & c)
HD 139461 139461 76603 15h 38m 40.07s −08° 47′ 29.1″ 6.45 4.47 81 F6V
30 Lib 30 136801 75294 15h 23m 01.78s −15° 08′ 02.7″ 6.46 −0.43 780 K4III suspected variable
HD 134946 134946 74490 15h 13m 17.43s −24° 00′ 29.8″ 6.47 0.96 412 B8III
HD 126251 126251 70452 14h 24m 40.90s −11° 40′ 10.7″ 6.49 1.72 293 F4III
HD 126363 126363 70501 14h 25m 17.63s −13° 21′ 11.4″ 6.49 0.48 520 K2III
HD 127964 127964 71295 14h 34m 50.72s −20° 26′ 21.8″ 6.49 0.12 613 A3V
HD 134758 134758 74391 15h 12m 12.04s −19° 06′ 23.1″ 6.49 0.33 555 K4III
HD 140722 140722 77235 15h 46m 12.89s −28° 03′ 41.1″ 6.49 2.33 222 F0V
HD 136646 136646 75272 15h 22m 45.19s −29° 20′ 30.9″ 6.50 0.83 443 K0III
HD 133112 133112 73608 15h 02m 44.9s −03° 01′ 53″ 6.60 323 A6IV-V WASP-189, has a planet (b)[3]
17 Lib 17 132230 73249 14h 58m 13.42s −11° 09′ 17.1″ 6.61 1.30 376 A1V
33 Lib ζ2 33 GZ 137949 75848 15h 29m 34.78s −17° 26′ 27.4″ 6.69 1.94 291 Ap rapidly oscillating Ap star, Vmax = 6.66m, Vmin = 6.71m, P = 4.85 d
HD 141569 141569 77542 15h 49m 57.75s −03° 55′ 16.3″ 7.12 379 A0Ve has a protoplanetary disk
3 Lib 3 128756 71652 14h 39m 22.01s −25° 01′ 43.0″ 7.20 663 K0III
HD 140283 140283 76976 15h 43m 03.10s −10° 56′ 00.6″ 7.21 190 sdF3 one of the oldest stars known; suspected variable
FY Lib FY 132112 73213 14h 57m 46.55s −12° 26′ 15.3″ 7.23 1310 M5III semiregular variable, Vmax = 6.5m, Vmin = 7.78m, P = 179.7 d
KU Lib KU 128987 71743 14h 40m 31.11s −16° 12′ 33.4″ 7.23 77 G8V BY Dra variable; member of the α Lib system
ES Lib ES 135681 74765 15h 16m 48.61s −13° 02′ 21.1″ 7.25 378 A3III β Lyr variable, Vmax = 7.1m, Vmin = 7.57m, P = 0.88 d
HD 141937 141937 77740 15h 52m 17.55s −18° 26′ 09.8″ 7.25 4.63 109 G2/G3V has a planet (b)
HD 134796 134796 74401 15h 12m 20.95s −16° 24′ 39.86″ 7.28 7.26 B9V
HD 136905 GX 136905 75325 15h 23m 26.06s −06° 36′ 37.8″ 7.31 378 G8IVp RS CVn variable, ΔV = 0.08m, P = 11.13 d
HD 134214 HI 134214 74145 15h 09m 02.41s −13° 59′ 58.7″ 7.48 335 Ap... rapidly oscillating Ap star, ΔV = 0.007m
HM Lib HM 137613 75694 15h 27m 48.32s −25° 10′ 10.1″ 7.54 1940 C PV Tel variable, Vmax = 7.42m, Vmin = 7.63m
HD 134701 134701 15h 11m 51.55s −16° 36′ 40.16″ 7.70 8.20 F5V
HD 133803 133803 73990 15h 07m 15.0s −29° 30′ 16″ 8.12 408 A9V has two planets
HD 133131 A 133131 73674 15h 03m 35.8s −27° 50′ 28″ 8.4 G2V has two planets
HD 133131 B 133131 73674 15h 03m 35.8s −27° 50′ 28″ 8.42 G2 has a planet
HD 128598 128598 71567 14h 38m 11.78s −14° 57′ 17.2″ 8.76 3080 K1IV/V used to discover Uranus's rings
UZ Lib UZ 76086 15h 32m 23.21s −08° 32′ 00.9″ 9.12 525 K0III RS CVn variable, Vmax = 8.85m, Vmin = 9.62m, P = 4.77 d
HD 134440 134440 74234 15h 10m 12.97s −16° 27′ 47.5″ 9.43 93 K2V peculiar metal abundance; suspected variable
EH Lib EH 73315 14h 58m 55.92s −00° 56′ 53.1″ 9.83 2.00 1,197 A5V δ Sct variable, Vmax = 9.35m, Vmin = 10.08m, P = 0.09 d
HD 139139 139139 15h 37m 06.21s −19° 08′ 33.1″ 9.84 351 G3/5V has unusual dimming periods
VZ Lib VZ 76050 15h 31m 51.76s −15° 41′ 10.2″ 10.27 667 F5 W UMa variable, Vmax = 10.13m, Vmin = 10.63m, P = 0.36 d
Gliese 581 HO 74995 15h 19m 26.82s −07° 43′ 20.2″ 10.55 11.57 20 M3 BY Dra variable, Vmax = 10.56m, Vmin = 10.58m; has 3 planets (b, c, e)
WASP-109 15h 28m 13.0s −16° 24′ 39″ 11.4 3.81 1076 F4V has a transiting planets
HE 1523-0901 15h 26m 01.07s −09° 11′ 38.9″ 11.50 one of the oldest stars known
HP Lib HP 15h 35m 53.08s −14° 13′ 12.2″ 13.65 Bpec AM CVn star and V777 Her variable, Vmax = 13.65m, Vmin = 13.8m, P = 0.013 d
K2-315 15h 12m 5.06s −20° 06′ 29.39″ 17.67 13.89 185.3 M3.5V has a transiting planet (b)
2MASS 1507-1627 15h 07m 47.69s −16° 27′ 38.6″ 22.14 23.9 L5.5 brown dwarf
GW Lib GW 15h 19m 55.35s −25° 00′ 24.5″ WZ Sge variable
WISE 1541-2250 15h 41m 51.66s −22° 50′ 25.0″ 18.6 Y0 brown dwarf
IC 1059 14h 50m 42.54s −00° 52′ 33.1″ a galaxy discovered in 1893 by Stephane Javelle[4][5][6]
Table legend:

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List of stars in Libra

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The list of stars in Libra encompasses all cataloged stellar objects lying within the precisely defined boundaries of the Libra constellation, one of the 88 modern constellations officially recognized by the (IAU) since 1922. Representing the balance scales in the zodiac, Libra spans 538 square degrees primarily in the southern celestial sky, visible from latitudes +65° to -90°, and is best observed during late spring and early summer in the . The constellation is notably faint, containing 83 stars brighter than 6.0 that are visible to the under dark skies, with no individual star exceeding magnitude 2.5 in brightness. Among these, the four principal stars—Alpha Librae, Beta Librae, Gamma Librae, and Sigma Librae—form the asterism's distinctive quadrilateral shape, with Bayer designations assigned by in 1603 and proper names approved by the IAU's Working Group on Star Names. , or Zubeneschamali ("the northern claw" in ), stands as the brightest at magnitude 2.61; it is a blue-white main-sequence star of spectral type B8V, approximately 3.5 times the Sun's mass and 185 light-years distant. , known as Zubenelgenubi ("the southern claw"), is the second-brightest at a combined magnitude of 2.75; this multiple features a blue-white A3V primary and a white F3V secondary separated by 231 arcseconds, located 77 light-years away. Further notable entries include Gamma Librae (Zubenelhakrabi, "the claws") at magnitude 3.91, an evolved orange giant of type K0III situated 163 light-years from , and Sigma Librae (Brachium, "the arm"), a of type M0III with magnitude 3.29 and a distance of 288 light-years. Libra's catalog also highlights unique objects such as (Methuselah), a metal-poor estimated at 14.2 ± 0.4 billion years old—nearly as ancient as the itself—and located 190 light-years away, as well as four known exoplanet-hosting like , a 20.5 light-years distant with multiple terrestrial planets (b, c, d, e). These stars are systematically listed in astronomical databases by criteria such as , , spectral classification, and variability, drawing from surveys like the Hipparcos Catalogue and mission data, which reveal Libra's abundance of binary and multiple systems alongside its relative scarcity of Messier deep-sky objects. The constellation's underscores its historical role in ancient Babylonian and Roman astronomy, where it symbolized and equilibrium.

Overview

Constellation background

Libra is a zodiacal constellation situated in the , positioned along the between Virgo to the west and to the east. It shares borders with Serpens Caput to the north, to the northeast, to the southeast, to the south, Hydra to the southwest, and Virgo to the northwest, forming a compact region near the . The boundaries of Libra were formally delimited by the (IAU) in 1930 as part of the effort to standardize the 88 modern constellations, encompassing an area of 538 square degrees and ranking it 29th in size among them. Libra is best visible from the during late spring and early summer, particularly from May to , when it rises higher in the evening sky around 9 p.m. local time. In ancient around 2000 BCE, the stars of Libra were associated with a balance or scales, a concept later adopted and formalized by the Romans in the BCE as the scales of justice, symbolizing equilibrium and fairness under the goddess or Justitia. Unlike many constellations, Libra lacks prominent Messier or New General Catalogue (NGC) deep-sky objects within its boundaries, such as galaxies or clusters that dominate other regions, thereby directing observational focus toward its stellar population. Stars within Libra are identified using designation systems like those of and Flamsteed, which provide systematic naming for cataloging purposes.

Designation systems for stars

Stars in the constellation Libra are identified through various designation systems that facilitate precise cataloging and reference in astronomical and . These systems evolved from early modern efforts to map the systematically to contemporary databases providing high-accuracy astrometric . The system, introduced by in his 1603 star atlas Uranometria, assigns Greek letters to stars within a constellation based on their apparent , followed by the genitive form of the constellation name, such as for the brightest star in Libra. ordered the letters from alpha for the brightest to for fainter ones, though not always strictly adhering to exact magnitudes due to observational limitations of the time. This system remains a standard for naming prominent stars visible to the . Complementing the Bayer method, the Flamsteed numbering system was developed by , the first , in his 1725 publication Historia Coelestis Britannica. It assigns sequential numbers to stars in each constellation ordered by increasing , prefixed by the constellation , for example, 11 Librae. Flamsteed's catalog included positions for nearly 3,000 stars derived from telescopic observations at Greenwich Observatory, providing a more positional approach than Bayer's brightness-based scheme. In the 20th century, the Henry Draper Catalogue (HD), compiled at Observatory and published between 1918 and 1924, introduced numerical designations for over 225,000 stars based on their spectral classifications and positions, with Libra stars receiving HD numbers like HD 130819 for α¹ Librae. This catalog, initiated in memory of Henry Draper, marked a shift toward spectroscopic analysis alongside positional data. Derived from it, the Harvard Revised Catalogue (HR), also known as the , assigns HR numbers to about 9,000 brighter stars (magnitude 6.5 or brighter), updating HD entries with refined photometry and proper motions; for instance, is HR 5685. Modern astrometric catalogs provide even greater precision through space-based observations. The , released by the in 1997 from data collected by the satellite (1989–1993), includes HIP numbers for 118,218 stars with sub-arcsecond accuracy in positions, parallaxes, and proper motions, such as HIP 76333 for Gamma Librae. Building on this, the mission's Data Release 3 (Gaia DR3), published by ESA in 2022 from observations spanning 2014–2017, offers designations for over 1.8 billion sources, including unprecedented parallaxes for millions of stars in Libra, enabling detailed studies of their distances and motions. In addition to these systematic designations, the (IAU) has approved a select number of traditional proper names for stars in Libra through its Working Group on Star Names (WGSN), standardizing historical nomenclature for cultural and scientific consistency. These include Zubenelgenubi for , Zubeneschamali for , Zubenelhakrabi for Gamma Librae, and Brachium for Sigma Librae, all approved in 2016 based on longstanding origins denoting "southern claw," "northern claw," "the scorpion's claw," and "the arm," respectively.

Brightest stars

Alpha to Delta Librae

The four brightest stars in Libra, with apparent magnitudes ranging from 2.61 to 3.91, form the primary visual asterism of the constellation, outlining its distinctive shape against the southern autumn sky. These stars, designated by early letters but ordered here by brightness, include as the brightest, followed by , Sigma Librae, and Gamma Librae. Their positions span right ascensions from about 14h 51m to 15h 28m and declinations from -25° to -8°, making them prominent for observers in the during late summer evenings. Physical characteristics vary from hot main-sequence stars to a cool giant, reflecting diverse evolutionary stages within 75 to 292 light-years of . Beta Librae, also known as Zubeneschamali, is the brightest star in the constellation at an apparent visual magnitude of 2.61. It is a main-sequence star of type B8V, characterized by a hot surface around 12,300 K that produces a striking blue-white hue. Notably, its spectrum lacks prominent calcium absorption lines, a rarity among stars that contributes to its clean, unabsorbed appearance in the violet end. Located approximately 160 light-years away, it serves as a key reference for spectroscopic studies due to this uncomplicated line profile. Alpha Librae, traditionally called Zubenelgenubi, ranks second in brightness with a combined of 2.75 for its close visual pair. The primary component is a main-sequence star of spectral type A3V, part of a multiple system where the inner spectroscopic binary has an of about 5,870 days (roughly 16 years). The overall system, including the wider visual companion, exhibits a longer orbital dynamic estimated at around 180 years for the primary pair's interaction. At a of 77 light-years, it appears as a challenging naked-eye double, resolvable with into components separated by about 4 arcminutes. Sigma Librae, known as Brachium, is the third-brightest at magnitude 3.29 and stands out as a of spectral type M3III. Situated 292 light-years distant, it exhibits semi-regular variability with small changes, though its core properties remain stable for visual observation. This evolved star marks the southern extent of Libra's asterism, providing contrast to the hotter blue stars nearby. Gamma Librae, also known as Zubenelhakrabi, is the fourth-brightest at magnitude 3.91 and is an evolved orange giant of spectral type G8.5III. Located approximately 163 light-years away, it forms the eastern vertex of the quadrilateral asterism.
DesignationProper NameApparent MagnitudeSpectral TypeDistance (ly)Right Ascension (J2000)Declination (J2000)
β LibraeZubeneschamali2.61B8V16015h 17m 00s-09° 23'
α LibraeZubenelgenubi2.75A3V7714h 51m 00s-16° 02'
σ LibraeBrachium3.29M3III29215h 04m 04s-25° 17'
γ LibraeZubenelhakrabi3.91G8.5III16315h 28m 00s-14° 38'

Epsilon to Iota Librae

Epsilon Librae is an F4V main-sequence star situated approximately 94 light-years from the Sun, exhibiting an apparent visual magnitude of 4.92. It occupies a position on the southern boundary of the constellation, helping to define its lower edge relative to the brighter to the north. Zeta Librae is a multiple with components including an A3V main-sequence primary at a distance of approximately 260 light-years, with the system having an around 5.0. It lies centrally within the constellation, positioned between Epsilon Librae and the brighter Gamma Librae. Iota Librae is a B9IVpSi main-sequence star located 378 light-years away, displaying an of 4.54 and serving as a key point in the western arm of the scales asterism, extending the outline from Delta Librae westward. These stars, designated under the system as outlined in the designation systems section, form the next tier of principal members in Libra after the brightest quartet, with magnitudes between 4.54 and 4.92 contributing to the constellation's overall framework.
Star NameBayer DesignationApparent MagnitudeSpectral TypeDistance (ly)Position Relative to Brighter Stars
Epsilon LibraeF4V94Southern boundary, southeast of
Zeta Libraeζ Lib5.0A3V (primary)260Central, south of Gamma Librae and east of Epsilon
Iota Libraeι Lib4.54B9IVpSi378Western arm, west of Delta Librae
These fainter principal stars are readily visible to the naked eye under dark skies but benefit from binoculars for clearer resolution in light-polluted environments, enhancing their contribution to Libra's distinctive quadrilateral shape alongside Alpha, Beta, Gamma, and Sigma Librae. Delta Librae, at magnitude 4.92 and spectral type B9V, is a main-sequence star located about 304 light-years away and contributes to the extended outline of the constellation, though fainter than the primary asterism. It exhibits variability as an eclipsing binary.

Stars hosting exoplanets

Gliese 581 system

is a star of type M3V, located at a distance of 20.3 light-years from the Sun in the constellation Libra. With an apparent visual magnitude of 10.57, it is too faint to be observed without a . The star's coordinates are 15ʰ 19ᵐ 25.⁵⁵ˢ and −07° 43′ 21.″70, and measurements indicate a of 1225 mas/yr, reflecting its relatively high transverse velocity across the sky. The planetary system around was discovered through observations conducted between 2005 and 2009 using spectrographs such as HARPS on the ESO 3.6-meter telescope and HIRES on the Keck I telescope. Currently, three s are confirmed: Gliese 581b, c, and e, all with minimum masses between and sizes. b, the closest to the star, has an of 5.37 days; e orbits every 3.15 days; and c completes its in 12.92 days. These close-in s result from the star's low , placing the planets within about 0.03 to 0.07 AU. Earlier claims of additional planets, including f, d, and g—bringing the total to six—were based on further data analyzed from 2007 to 2010, but subsequent reanalyses attributed their signals to stellar activity rather than planetary motion. The system holds scientific significance as one of the earliest examples of low-mass planets orbiting an M-dwarf star, highlighting the prevalence of such compact systems around red dwarfs, which constitute about 75% of stars in the . Planets c and the proposed d were initially considered candidates for due to their positions near the conservative , where liquid water might exist on a rocky surface, with d's 66.6-day orbit placing it squarely within that region for the star's of around 3200 K. However, the non-confirmation of d and g, along with models showing c receives excessive stellar flux akin to , has tempered optimism for Earth-like conditions, though the system continues to inform studies on and atmospheric retention in multi-planet setups. Red dwarfs like are common hosts, often featuring tightly packed orbits that challenge planetary formation theories.

Other exoplanet host stars in Libra

In addition to the Gliese 581 system, four other stars in the constellation Libra host confirmed exoplanets, all detected via the radial velocity method. These systems, cataloged in the NASA Exoplanet Archive as of November 2025, provide insights into planetary architectures around Sun-like and evolved stars. The total number of confirmed exoplanet-hosting stars in Libra stands at five, reflecting ongoing surveys that prioritize radial velocity monitoring for nearby targets. HD 141937, a G2/G3V main-sequence star similar to the Sun, lies approximately 109 light-years away. It hosts a single , HD 141937 b, with a minimum mass of about 9.7 masses and an of roughly 1.8 years. Discovered in 2002 through observations with the CORALIE spectrograph at the , this orbits at a semi-major axis of 1.52 AU, placing it in a temperate zone analogous to 's but around a slightly metal-rich host ( [Fe/H] ≈ +0.11). The system's simplicity highlights early successes in identifying Jovian companions. HD 134987, also known as 23 Librae, is a G4V at a distance of 85 light-years. This star hosts two : the inner HD 134987 b, a -mass world (minimum 1.59 masses) with a 3.4-year at 1.64 AU, and the outer HD 134987 c, a (minimum 1.52 masses) orbiting every 6.7 years at about 3.3 AU. Both were identified in 1999 using the and Carnegie Planet Search with the Hamilton spectrograph, marking one of the earliest multi-planet systems detected. The ' eccentric orbits (e ≈ 0.3 for b) suggest potential dynamical interactions. Gamma Librae (HD 138905), an evolved K0III 163 light-years distant, is orbited by two gas giants. Gamma Librae b has a minimum mass of 1.13 masses and a 415-day period at 1.25 AU, while Gamma Librae c is more massive at 5.23 masses with a 2.65-year orbit at 2.18 AU. Announced in 2018 from data, these orbit a metal-poor host ([Fe/H] ≈ -0.37) that has expanded to about 11 solar radii post-main-sequence evolution. The system exemplifies survival around post-main-sequence stars. HN Librae (Gliese 555), a of spectral type M3.5V located 20 light-years away, hosts one confirmed sub-Neptunian , HN Librae b, with a minimum mass of 5.46 masses and an of 36.1 days at 0.142 AU. This lies within the star's . Discovered in 2023 using observations, the system is notable for its proximity and potential for habitability studies around cool stars. The following table summarizes key parameters for these host stars and their systems:
Star DesignationSpectral TypeDistance (ly)Number of Confirmed PlanetsDiscovery MethodDiscovery YearPrimary Reference
Gliese 581M3V20.33Radial Velocity2005Bonfils et al. (2005)
HD 141937G2/G3V1091Radial Velocity2002Udry et al. (2002)
HD 134987 (23 Librae)G4V852Radial Velocity1999Marcy et al. (2000)
Gamma Librae (HD 138905)K0III1632Radial Velocity2018Takarada et al. (2018)
HN Librae (Gliese 555)M3.5V201Radial Velocity2023Luque et al. (2023)
QV Librae has been suggested as a potential host based on preliminary photometric and data, but no planets are confirmed as of 2025 and further observations are needed.

Variable stars

Beta Librae and other bright variables

, also known as Zubeneschamali, is a suspected showing small brightness variations with an of 0.03 magnitudes. This variability was first suspected in the 19th century through historical brightness comparisons with nearby stars like . Alpha Librae, or Zubenelgenubi, is a multiple including a close spectroscopic binary, but it does not exhibit significant photometric variability. Among other bright variables in Libra, Sigma Librae stands out as a semi-regular variable and evolved , showing amplitude variations of 0.10–0.15 magnitudes over a period of 20 days, attributed to irregular pulsations in its extended atmosphere. This star's variability was noted in surveys and is tracked by AAVSO. The exhibits multiple periods, but the dominant one reflects convective instability in the star's envelope.

Fainter variable stars

In the constellation Libra, several fainter variable stars, with apparent magnitudes typically below 4, exhibit significant variability that requires telescopic observation for detailed study. These stars include long-period pulsators and interacting binaries, contributing to our understanding of late-stage and binary dynamics. The General Catalogue of Variable Stars (GCVS) lists over 20 such variables in Libra, predominantly long-period types like Miras and semiregulars, alongside a smaller number of cataclysmic variables characterized by accretion-driven outbursts. R Librae is a notable , a type of pulsating that undergoes dramatic brightness changes due to radial pulsations. It displays an of approximately 7 magnitudes in the visual band, with a well-defined period of 244 days. U Librae is a , a pulsating long-period . Its variability shows an of several magnitudes, driven by the giant's pulsations. V Librae is a long-period variable (Mira type), a pulsating . It has an amplitude of several magnitudes and a period of 256 days, reflecting pulsations in its envelope. These fainter variables in Libra, often monitored by amateur and professional networks like the AAVSO, highlight the diversity of variability mechanisms beyond brighter naked-eye stars, from intrinsic pulsations to binary interactions.

Multiple star systems

Alpha Librae system

The system, also known as Zubenelgenubi, is a hierarchical multiple at a distance of approximately 76 light-years from the Sun. It comprises a visual binary pair with components separated by about 4 arcseconds, making it resolvable using small telescopes such as . The system exhibits common of roughly 0.15 arcseconds per year. The brighter component, α¹ Librae (spectral type A0V), is itself a double-lined spectroscopic binary consisting of two main-sequence stars with masses of 1.92 M⊙ and 1.60 M⊙. These stars orbit each other with a period of 70.34 days, an eccentricity of 0.41, and a semi-amplitude of 43.1 km s⁻¹ for the secondary. The systemic of this subsystem is -23.8 km s⁻¹. This close pair represents an early evolutionary stage of main-sequence binaries in the intermediate-mass range. The fainter visual component, α² Librae (spectral type F3V), forms another spectroscopic binary pair with a main-sequence F-type primary and a secondary main-sequence star of similar , orbiting at a separation of 0.383 arcseconds (approximately 10 AU). The inner of this pair is 16 years. The es of these components are estimated at around 1.95 M⊙ for the primary and 1.8 M⊙ for the secondary, consistent with main-sequence . measurements reveal amplitudes of about 4.3 km s⁻¹ for the primary and 5.5 km s⁻¹ for the secondary. The outer encompassing the two visual components spans a wide separation equivalent to several hundred AU, resulting in an exceeding 200,000 years. This long-period configuration highlights the stability of the hierarchical architecture, with the inner binaries dominating short-term dynamics while the outer motion contributes to the system's overall across the sky. The system's variability arises partly from eclipses in the close α¹ Librae binary.

Gamma and other multiple systems

Gamma Librae, also known as Zubenelhakrabi, is a multiple consisting of a G8.5III giant primary with an apparent visual magnitude of 3.91. The is hierarchical, featuring a close inner pair (Aa and Ab) separated by approximately 0.1 arcseconds, though this pair is often unresolved in observations and may require speckle for . A wider companion (B) orbits at about 42 arcseconds from the primary, likely forming a physical triple rather than an optical alignment. Upsilon Librae is another notable in the constellation, classified as a K3.5III giant primary with a visual magnitude of 3.59. The secondary component is a faint magnitude 10.8 star separated by roughly 3.5 arcseconds from the primary, with an estimated on the order of centuries based on visual binary dynamics. This separation allows the pair to be resolved in small telescopes, highlighting its status as a visual binary. The system's components share similar proper motions, indicating gravitational binding. Libra hosts numerous other multiple systems documented in the Washington Double Star Catalog (WDS), which catalogs astrometric doubles and multiples across the sky. For instance, 25 Librae is an A2V star of magnitude 6.07, occasionally noted in proximity to Iota Librae but lacking confirmed multiplicity in current databases, serving instead as an example of optical alignments in the field. Overall, the WDS records dozens of visual and spectroscopic multiples in Libra, with angular separations ranging from sub-arcsecond close pairs detectable via to wider companions exceeding 100 arcseconds, reflecting the diverse hierarchies typical of stellar populations in this region. These systems underscore the prevalence of binaries and higher-order multiples, estimated at around 15% of cataloged stars in the constellation based on WDS entries for visual doubles.

Other notable stars

Methuselah star (HD 140283)

, commonly referred to as the Methuselah star, is a metal-poor of spectral type G0IV located in the constellation Libra, approximately 202 light-years from . With an apparent visual magnitude of 7.205, it is positioned near the center of the constellation and can be observed with small telescopes or under dark skies. This Population II halo is notable for its high across the sky, which first drew attention to its anomalous properties. The star's age has been a subject of intense study due to its apparent extreme antiquity. Observations with the refined its estimated age to 14.46 ± 0.8 billion years, initially suggesting it might exceed the age of the (approximately 13.8 billion years) based on earlier measurements. Subsequent precise data from the mission resolved this discrepancy by providing a more accurate , confirming the star's age is consistent with cosmological models while establishing it as one of the oldest known stars in the solar neighborhood. A 2025 asteroseismic analysis using TESS data further refined the age to 14.2 ± 0.4 billion years, with a of 0.75 ± 0.01 M⊙ and of 2.078 R⊙. HD 140283 exhibits extremely low , with an iron abundance of [Fe/H] = -2.3 relative to the Sun, indicating it formed from gas with minimal heavy elements shortly after the . It also displays a relatively high abundance for such a metal-poor star, which aligns with the Spite plateau and provides key constraints on models for primordial light element production. First cataloged in the Henry Draper Catalogue during the 1910s as part of early 20th-century spectroscopic surveys, HD 140283 was recognized for its fast motion and low by the 1950s. Its age estimates were significantly refined in the 2000s through Hubble observations of its distance and evolutionary stage, solidifying its status as a benchmark for understanding early .

Additional remarkable stars

The catalog records approximately 83 stars in Libra brighter than magnitude 6.

References

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