TIC 168789840

{{short description|Sextuple star in the constellation Eridanus}}

{{Starbox image

| image=

{{Location mark

|image=Eridanus_IAU.svg|float=center|width=280

|alt=|label=|position=right

}}

|caption=Location of TIC 168789840 (red circle)

}}

{{Starbox observe

| epoch = J2000

| constell = Eridanus

| ra = {{RA|04|14|04.867}}

| dec = {{DEC|-31|55|22.36}}

| appmag_v = 11.51

}}

{{Starbox astrometry

| radial_v =

| prop_mo_ra = 12.082

| prop_mo_dec = 9.513

| parallax = 1.6861

| p_error = 0.4296

| parallax_footnote =

| dist_ly = {{val|1900|225}}

| dist_pc = {{val|584|70}}

| absmag_v =

}}

{{Starbox detail

| source =

| component1 = System

| age_gyr = {{val|3.160|0.624}}

}}

{{Starbox detail|no_heading=y

| component1 = A1

| mass = {{val|1.25|0.05}}

| temperature = {{val|6,400|125|fmt=commas}}

| luminosity = 3.39

| radius = {{val|1.49|0.07}}

| gravity = 4.18

| rotational_velocity = 48.5

| component2 = A2

| mass2 = {{val|0.56|0.04}}

| temperature2 = {{val|3,923|100|fmt=commas}}

| luminosity2 = 0.07

| radius2 = {{val|0.52|0.04}}

| gravity2 = 4.73

| rotational_velocity2 = 17.5

}}

{{Starbox detail|no_heading=y

| component1 = B1

| mass = {{val|1.30|0.08}}

| temperature = {{val|6,365|170|fmt=commas}}

| luminosity = 3.95

| radius = {{val|1.69|0.22}}

| gravity = 4.12

| rotational_velocity = 10.1

| component2 = B2

| mass2 = {{val|0.66|0.03}}

| temperature2 = {{val|4,290|110|fmt=commas}}

| luminosity2 = 0.12

| radius2 = {{val|0.62|0.02}}

| gravity2 = 4.67

| rotational_velocity2 = 3.8

}}

{{Starbox detail|no_heading=y

| component1 = C1

| mass = {{val|1.23|0.10}}

| temperature = {{val|6,350|160|fmt=commas}}

| luminosity = 2.74

| radius = {{val|1.45|0.28}}

| gravity = 4.24

| rotational_velocity = 51.5

| component2 = C2

| mass2 = {{val|0.59|0.07}}

| temperature2 = {{val|3,889|190|fmt=commas}}

| luminosity2 = 0.07

| radius2 = {{val|0.56|0.07}}

| gravity2 = 4.72

| rotational_velocity2 = 20.9

}}

{{Starbox catalogue

| names = 2MASS J04140483-3155223, GSC 07037-00089, TYC 7037-89-1, RAVE J041404.8-315523, Gaia DR2 4882954370431549824

}}

{{Starbox reference

| Simbad = TYC+7037-89-1

}}

TIC 168789840, also known as TYC 7037-89-1, is a stellar system with six stars. Three pairs of binary stars circle a common barycenter. While other systems with three pairs of stars have been discovered, this was the first system where the stars can be observed eclipsing one another, as the Earth lies approximately on their planes of rotation.

Discovery

File:Transiting Exoplanet Survey Satellite artist concept (transparent background).png

The Transiting Exoplanet Survey Satellite identified that the star system consisted of six eclipsing stars. The discovery was announced in January 2021. It is approximately {{convert|584|pc|ly|order=flip}} from Earth, in the constellation Eridanus, west of the river asterism's sharpest bend, Upsilon2 Eridani, often called Theemin.{{cite web |author=Staff |title=Finding the constellation which contains given sky coordinates |url=http://djm.cc/constellation.html |date=2 August 2008 |work=DJM.cc |access-date=16 July 2020}} To be seen the group needs strong magnification from Earth as is much fainter than red clump giant star Theemin and is about nine times further away.

Orbits

File:TIC168789840LightCurve.png for TIC 168789840, plotted from TESS data]]

Two sets of the binaries co-orbit relatively closely, while the third pair of stars takes 2,000 years to orbit the entire system barycenter. The inner A pair and C pair orbit each other in 3.7 years. These are, as taken from the paired B stars, about {{val|250|ul=AU}} away (specifically the mean telescopic separation is {{val|423|ul=mas}}) and the three lettered pairs, as groups, have been resolved (the three gaps made out). From A pair to C pair is calculated to be {{val|4|u=AU}} ({{val|7|u=mas|p=∼}}) apart, which means this gap should be resolvable using speckle interferometry which has not yet been achieved.

Note, the three binaries (here close pairs) A, B, and C are resolved only as systems, the pairs being just {{solar radius|6.9|link=y}} ({{val|0.054|u=mas|p=∼}}), {{solar radius|21.4}} ({{val|0.168|u=mas|p=∼}}), and {{solar radius|6.1}} ({{val|0.047|u=mas|p=∼}}) apart, respectively.

According to Jeanette Kazmierczak of NASA's Goddard Space Flight Center:

class="wikitable"

: The stars in the A and C systems orbit each other roughly every day and a half, and the two binaries orbit each other about every four years. The B binary’s members circle each other about every eight days, but the pair is much farther away, orbiting around the inner systems roughly every 2,000 years.

Stellar characteristics

The primary stars of all three close binaries are slightly hotter and brighter than the Sun, while the secondary stars are much cooler and dimmer. Because the two closely bound pairs are so close, only the third, more distant pair could have planets. The primaries are all beginning to evolve away from the main sequence, while the less massive and longer-lived secondaries are all still firmly on the main sequence and fusing hydrogen in their cores.

References

{{Reflist|refs=

{{cite web |title=MAST: Barbara A. Mikulski Archive for Space Telescopes |url=https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html |publisher=Space Telescope Science Institute |access-date=8 December 2021}}

{{cite journal |arxiv=2101.03433 |last1=Powell |first1=Brian P. |last2=Kostov |first2=Veselin B. |last3=Rappaport |first3=Saul A. |last4=Borkovits |first4=Tamas |last5=Zasche |first5=Petr |last6=Tokovinin |first6=Andrei |last7=Kruse |first7=Ethan |last8=Latham |first8=David W. |last9=Montet |first9=Benjamin T. |last10=Jensen |first10=Eric L. N. |last11=Jayaraman |first11=Rahul |last12=Collins |first12=Karen A. |last13=Masek |first13=Martin |last14=Hellier |first14=Coel |last15=Evans |first15=Phil |last16=Tan |first16=Thiam-Guan |last17=Schlieder |first17=Joshua E. |last18=Torres |first18=Guillermo |last19=Smale |first19=Alan P. |last20=Friedman |first20=Adam H. |last21=Barclay |first21=Thomas |last22=Gagliano |first22=Robert |last23=Quintana |first23=Elisa V. |last24=Jacobs |first24=Thomas L. |last25=Gilbert |first25=Emily A. |last26=Kristiansen |first26=Martti H. |last27=Colon |first27=Knicole D. |last28=LaCourse |first28=Daryll M. |last29=Olmschenk |first29=Greg |last30=Omohundro |first30=Mark |title=TIC 168789840: A Sextuply-Eclipsing Sextuple Star System |journal=The Astronomical Journal |year=2021 |volume=161 |issue=4 |page=162 |doi=10.3847/1538-3881/abddb5 |bibcode=2021AJ....161..162P |s2cid=231573303 |display-authors=29 |doi-access=free }}

{{cite news

| url = https://exoplanets.nasa.gov/news/1672/discovery-alert-first-six-star-system-where-all-six-stars-undergo-eclipses/

| title = Discovery Alert: First Six-star System Where All Six Stars Undergo Eclipses

| work = NASA's Goddard Space Flight Center

| author = Jeanette Kazmierczak

| date = 2021-01-27

| location = Greenbelt, Maryland

| archive-url = https://web.archive.org/web/20210127224045/https://exoplanets.nasa.gov/news/1672/discovery-alert-first-six-star-system-where-all-six-stars-undergo-eclipses/

| archive-date = 2021-01-27

| access-date = 2021-01-29

| url-status = live

| quote = The system, also called TIC 168789840, is the first known sextuple composed of three sets of eclipsing binaries, stellar pairs whose orbits tip into our line of sight so we observe the stars alternatively passing in front of each other.

}}

{{cite news

| url = http://www.sci-news.com/astronomy/tess-sextuply-eclipsing-six-star-system-09282.html

| title = TESS Discovers Sextuply-Eclipsing Six-Star System

| work = Sci-News

| author = Natali Anderson

| date = 2021-01-25

| archive-url = https://web.archive.org/web/20210126210223/http://www.sci-news.com/astronomy/tess-sextuply-eclipsing-six-star-system-09282.html

| archive-date = 2021-01-26

| access-date = 2021-01-29

| url-status = live

| quote = {{'}}Prior to the discovery of TIC 168789840, there were 17 known sextuple star systems according to the June 2020 update of the Multiple Star Catalog,{{'}} lead author Dr. Brian Powell of NASA’s Goddard Space Flight Center and colleagues wrote in their paper.

}}

{{cite news

| url = https://www.forbes.com/sites/jamiecartereurope/2021/01/28/you-should-know-about-the-weird-sextuple-star-system-just-found-by-nasa-where-six-suns-eclipse-each-other/?sh=60bfadcc7698

| title = A Weird 'Sextuple' Star System Has Been Found By NASA Where Six Suns Eclipse Each Other

| work = Forbes magazine

| author = Jamie Carter

| date = 2021-01-28

| page =

| location =

| isbn =

| language =

| trans-title =

| archive-url = https://web.archive.org/web/20210129101812/https://www.forbes.com/sites/jamiecartereurope/2021/01/28/you-should-know-about-the-weird-sextuple-star-system-just-found-by-nasa-where-six-suns-eclipse-each-other/?sh=60bfadcc7698

| archive-date = 2021-01-29

| access-date = 2021-01-29

| url-status = live

| quote =

}}

{{cite news

| url = https://www.wionews.com/science/astronomers-find-a-system-of-six-stars-made-of-three-eclipsing-binaries-359797

| title = Astronomers find a system of six stars made of three eclipsing binaries

| work = WION

| date = 2021-01-28

| location = Washington, DC

| archive-url = https://web.archive.org/web/20210128050008/https://www.wionews.com/science/astronomers-find-a-system-of-six-stars-made-of-three-eclipsing-binaries-359797

| archive-date = 2021-01-28

| access-date = 2021-01-29

| url-status = live

| quote = The primary stars in all three binaries are all slightly bigger and more massive than the Sun and about as hot. The system, also called TIC 168789840, is located about 1,900 light-years away in the constellation Eridanus.

}}

{{cite news

| url = https://www.nytimes.com/2021/01/23/science/six-stars-eclipses.html

| title = Six Stars, Six Eclipses: 'The Fact That It Exists Blows My Mind'

| work = The New York Times

| author = Robin George Andrews

| date = 2021-01-23

| archive-url = https://web.archive.org/web/20210128114723/https://www.nytimes.com/2021/01/23/science/six-stars-eclipses.html

| archive-date = 2021-01-28

| access-date = 2021-01-29

| url-status = live

| quote = But only one of the pairs could have any planets. Two of the system’s binaries orbit extremely close to one another, forming their own quadruple subsystem. Any planets there would likely be ejected or engulfed by one of the four stars. The third binary is farther out, orbiting the other two once every 2,000 years or so, making it a possible exoplanetary haven.

}}

{{cite journal

| title=The Tycho-2 catalogue of the 2.5 million brightest stars

| journal=Astronomy and Astrophysics

| last1=Høg | first1=E. | last2=Fabricius | first2=C.

| last3=Makarov | first3=V. V. | last4=Urban | first4=S.

| last5=Corbin | first5=T. | last6=Wycoff | first6=G.

| last7=Bastian | first7=U. | last8=Schwekendiek | first8=P.

| last9=Wicenec | first9=A. | display-authors=1

| volume=355 | pages=L27 | year=2000

| doi=10.1888/0333750888/2862 | bibcode=2000A&A...355L..27H }}

}}

Category:Astronomical objects discovered in 2021

Category:Eridanus (constellation)

Category:Eclipsing binaries

TIC 168789840

Discovery

Orbits

Stellar characteristics

See also

References