Nu2 Lupi

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NASA

Nu2 Lupi is a yellow-orange star
like our Sun, Sol. (See a Digitized
Sky Survey image of Nu2 Lupi
from the Nearby Stars Database.)

System Summary

Nu2 Lupi is located about 47.5 light-years (ly) from Sol. It lies in the southern part of (15:21:48.1-48:19:3.5, ICRS 2000.0) of Constellation Lupus, the Wolf. The star can be found: near Nu1 and Kappa1 Lupi; north of Zeta Lupi; southwest of Epsilon, Gamma, and Delta Lupi; south of Beta Lupi; and east of Kakkab (Alpha Lupi). As Nu2 Lupi has become one of the top 100 target stars for NASA's planned Terrestrial Planet Finder (TPF), images of this star and its position relative to the Milky Way in Earth's night sky are now available from the TPF-C team.

JPL, CalTech, NASA

Larger illustration

Astronomers have identified Nu2
Lupi as a prime target for the
Terrestrial Planet Finder (TPF),
now planned for launch between
2014 and 2020.

The Star

Nu2 Lupi is a yellow-orange main sequence dwarf star of spectral and luminosity type G2-5 V. Similar to Sol (Giusa Cayrel de Strobel, 1996), this "Solar analogue" may have roughly the same mass, around 99 percent of its diameter (Pasinetti-Fracassini et al, 2001; and Johnson and Wright, 1983, page 683), and 97 percent of its luminosity. It appears to be only around 58 percent as enriched than Sol in elements heavier than hydrogen ("metals") based on its abundance of iron (B.J. Taylor, 2003). Useful catalogue numbers and designations for the star include: Nu2 Lup, HR 5699, Gl 582, Hip 75181, HD 136352, CD-47 9919, CP(D)-47 7075, SAO 225697, LHS 395, LTT 6225, LFT 1200, and LPM 565.

Hunt for Planetary Objects

An Earth-type planet with liquid water on its surface would require a stable orbit centered around 0.98 AU from Nu2 Lupi -- just under the orbital distance of Earth in the Solar System. Such a planet would have an orbital period lasting close to an Earth year. However, given its conjectured young age, an Earth-sized planet is not likely to have developed an oxygen-rich atmosphere but is likely to be under heavy bombardment by asteroids and comets.

Astronomers are hoping to use NASA's Terrestrial Planet Finder (TPF) and the ESA's Darwin planned groups of observatories to search for a rocky inner planet in the so-called "habitable zone" (HZ) around Nu2 Lupi. As currently planned, the TPF will include two complementary observatory groups: a visible-light coronagraph to launch around 2014; and a "formation-flying" infrared interferometer to launch before 2020, while Darwin will launch a flotilla of three mid-infrared telescopes and a fourth communications hub beginning in 2015.

Closest Neighbors

The following table includes all star systems known to be located within 10 light-years (ly), plus more bright stars within 10 to 20 ly, of Nu2 Lupi.

Star System	Spectra & Luminosity	Distance (light-years)
CD-42 10934	K5 V	7.0
CD-56 6221	K3 V	9.0
HR 5864 AB	G6 V-IV DA7 /VII	9.9
* plus bright stars *		. . .
HR 5825	F5 V-IV	11
HD 147513 / HR 6094 AB	G3-5 V DA2 /VII	12
Beta Trianguli Australis 2?	F2 IV-III	14
Alpha Circini 3?	A3-F1 V-IIIp K5 V ?	16
Zeta Trianguli Australis 2	F9-G0 V ?	19
Mu Arae	G3-5 V	19

Other Information

Up-to-date technical summaries on these stars can be found at: the Astronomiches Rechen-Institut at Heidelberg's ARICNS, and the Nearby Stars Database. Additional information may be available at Roger Wilcox's Internet Stellar Database.

Known as an unidentified animal called Therion to the Ancient Greeks (possibly the Erymanthian boar captured alive by Hercules as one of his tasks), the constellation was linked with the Wolf by the time of Johannes Bayer (1572-1625) For more information on stars and other objects in Constellation Eridanus, go to Christine Kronberg's Lupus. An illustration is available at David Haworth's Lupus.

For more information about stars including spectral and luminosity class codes, go to ChView's webpage on The Stars of the Milky Way.

Note: Nominated as a "notable nearby star" by Ronald Botterweg.