Visible at latitudes between +15° and −90°. Best visible at 21:00 (9 p.m.) during the month ofSeptember.
Indus is aconstellation in the southern sky first professionally surveyed by Europeans in the 1590s and mapped on a globe byPetrus Plancius by early 1598. It was included on a plate illustrating southern constellations inBayer's sky atlasUranometria in 1603. It lies well south of theTropic of Capricorn but its triangular shape can be seen for most of the year from theEquator. It is elongated from north to south and has a complex boundary. The English translation of its name is generally given asthe Indian, though it is unclear which indigenous people the constellation was originally supposed to represent.
The constellation Indus as it can be seen by the naked eye.
Indus lacks stars among the sky's brightest 100 stars inapparent magnitude. Its brightest stars are two of third magnitude and three of fourth magnitude.
Alpha Indi, its brightest, is anorange giant of magnitude 3.1, 101 light-years away.Beta Indi is an orange giant of magnitude 3.7, 600 light-years distant.Delta Indi is a white star of magnitude 4.4, 185 light-years from Earth. The three form a near-perfectright-angled triangle, such that Beta marks the right angle and is in the south-east.
Epsilon Indi is one of the closest stars toEarth, approximately 11.8light years away. It is anorange dwarf of magnitude 4.7, meaning that theyellow dwarfSun is slightly hotter and larger.[4] The system has been discovered to contain a pair of binarybrown dwarfs, and has long been a prime candidate inSETI studies.[5][6] This star has the third-highestproper motion of all visible to the unaided eye, as ranks behindGroombridge 1830 and61 Cygni, and the ninth-highest overall. This will move the star intoTucana around 2640. It figures directly between Alpha and Beta.
Indus is home to one brightbinary star.Theta Indi is a binary star divisible in small amateur telescopes, 97 light-years from Earth. Its primary is a white star of magnitude 4.5 and its secondary is a white star of magnitude 7.0.[4] It figures close to the hypotenuse of the right-angled triangle of Alpha, Beta and Delta, the three brightest stars of Indus.
T Indi is the only brightvariable star in Indus. It is asemi-regular, deeply colouredred giant with a period of 11 months, 1900 light-years away. Its minimum magnitude is 7 and its maximum: 5.[4]
All Sky Automated Survey for SuperNovae (ASAS-SN) in 2015 detected asuperluminous supernova, namedASASSN-15lh (also designatedSN 2015L[8]). Based on the study conducted by Subo Dong and team from the Kavli Institute for Astronomy and Astrophysics (KIAA) at Peking University, it was approximately doubly luminous to any supernova detected, and at peak was almost 50 times more intrinsically luminous than theMilky Way.Its distance: approximately 3.82gigalight-years, denoting an age approximately half that of the universe.[9]
Indus (top middle) in an extract fromJohann Bayer'sUranometria, its first appearance in a celestial atlas.
The constellation was created byPetrus Plancius who made a fairly large celestial globe from the observations ofPieter Dirkszoon Keyser andFrederick de Houtman.[4] The first depiction of this constellation in a celestial atlas followed inJohann Bayer'sUranometria of 1603.[10][11] Plancius portrayed the figure as a nude male with three arrows in one hand and one in the other, as a native, lacking quiver and bow.[12] It is among the twelve constellations introduced by Keyser and de Houtman, which first appeared on a celestial globe in 1598.
^Zijlstra, Albert A.; Minniti, Dante (April 1999). "A Dwarf Irregular Galaxy at the Edge of the Local Group: Stellar Populations and Distance of IC 5152".The Astronomical Journal.117 (4):1743–1757.doi:10.1086/300802.
^Sawyer Hogg, Helen (1951). "Out of Old Books (Pieter Dircksz Keijser, Delineator of the Southern Constellations)".Journal of the Royal Astronomical Society of Canada.45: 215.Bibcode:1951JRASC..45..215S.
