70 Ophiuchi

{{about-distinguish|p Ophiuchi|Rho Ophiuchi{{!}}ρ (Rho) Ophiuchi}}

{{Starbox begin

| name=70 Ophiuchi

}}

{{Starbox image

|image={{Location mark

|image=Ophiuchus_constellation_map.svg

|alt=

|float=center

|width=280

|label=

|position=right

|mark=Red circle.svg

|mark_width=11

|x=254

|y=329

}}

|alt=70 Ophiuchi is located in the constellation Ophiuchus

|caption=Location of 70 Ophiuchi in the constellation Ophiuchus

}}

{{Starbox observe 3s

| epoch = J2000

| equinox =

| constell = Ophiuchus

| component1 = 70 Ophiuchi

| ra1 = {{RA|18|05|27.285}}

| dec1 = {{DEC|+02|29|00.36}}

| appmag_v1 = 4.00 - 4.03

| component2 = A

| ra2 = {{RA|18|05|27.248}}

| dec2 = {{DEC|+02|30|00.53}}

| appmag_v2 = 4.13

| component3 = B

| ra3 = {{RA|18|05|27.463}}

| dec3 = {{DEC|+02|29|56.21}}

| appmag_v3 = 6.07

}}

{{Starbox character

| class=K0V + K4V

| appmag_1_passband = B

| appmag_1 = 4.97/7.26

| appmag_3_passband = R

| appmag_3 = 3.6/5.6

| b-v= +0.82/+1.15

| u-b=+0.69

| variable= BY Dra or RS CVn

}}

{{Starbox astrometry

| component1 = 70 Oph A

| radial_v = {{val|-5.73|0.18}}

| prop_mo_ra = {{val|206.525}}

| prop_mo_dec = {{val|-1107.492|fmt=none}}

| pm_footnote =

| parallax = 195.5674

| p_error = 0.1964

| parallax_footnote =

| absmag_v = +5.627

| component2 = 70 Oph B

| radial_v2 = {{val|-9.47|0.22}}

| prop_mo_ra2 = {{val|333.292}}

| prop_mo_dec2 = {{val|-1068.354|fmt=none}}

| pm_footnote2 =

| parallax2 = 195.2166

| p_error2 = 0.1012

| parallax_footnote2 =

| absmag_v2 = +7.427

}}

{{Starbox visbin

| reference =

| period = {{val|88.435|0.017}}

| axis_unitless = {{val|4.526|0.007|ul="}}
({{val|23.6|0.5|ul=AU}})

| eccentricity = {{val|0.5005|0.0006}}

| inclination = {{val|121.1|0.1}}

| periarg = {{val|193.4|0.3}}

| periastron = {{val|45809|14|fmt=commas}}

| node = {{val|121.7|0.2}}

| k1 = {{Val|3.51|0.04}}

| k2 = {{val|4.25|0.05}}

}}

{{Starbox detail

| component1 = 70 Oph A

| mass = {{val|0.834|0.055}}

| radius = {{val|0.831|0.004}}

| metal_fe = {{val|0.04|0.05}}

| gravity = 4.5

| rotation = 19.7 days

| luminosity_bolometric = {{val|0.51|0.01}}

| habitable_inner = 0.623 AU

| habitable_outer = 1.242 AU

| temperature = 5,282

| age_gyr = {{Val|6.2|1.0}}

| component2 = 70 Oph B

| mass2 = {{val|0.782|0.064}}

| radius2 = {{val|0.670|0.009}}

| habitable_inner2 = 0.359 AU

| habitable_outer2 = 0.712 AU

| luminosity_bolometric2 = {{val|0.15|0.02}}

| temperature2 = 4,623

| metal2_fe = {{val|0.04|0.05}}

| age_gyr2 = {{Val|6.2|1.0}}

}}

{{Starbox catalog

| names = {{odlist | B=p Oph | F=70 Oph | V=V2391 Oph | BD=+02 3482 | GJ=702 | HD=165341 | HIP=88601 | HR=6752 | PLX=4137 | SAO=123107}}

| component1 = 70 Oph A

| names1 = {{odlist | LHS=458}}

| component2 = 70 Oph B

| names2 = {{odlist | LHS=459}}

}}

{{Starbox reference

| Simbad = V2391+Oph|sn=The system

| Simbad2 = TYC+434-5213-1|sn2=A

| Simbad3 = TYC+434-5212-1|sn3=B

| NSTED = HD-165341

| ARICNS = 01463

}}

70 Ophiuchi (p Ophiuchi) is a binary star system located 16.7 light-years away from the Earth. It is in the constellation Ophiuchus. At magnitude 4 it appears as a dim star visible to the unaided eye away from city lights.

History

In Ptolemy's 2nd-century Almagest star catalogue this star system is listed as a 4th magnitude star, the 28th (or 4th outside the constellation figure) in Ophiuchus. It is star No. 261 in this catalogue.

This star system was first catalogued as a binary star by William Herschel in the late 18th century in his study of binary stars. Herschel proved that this system is a gravitationally bound binary system where the two stars orbit around a common center of mass. This was an important contribution to the proof that Newton's law of universal gravitation applied to objects beyond the Solar System.

This star was once considered part of the obsolete constellation Taurus Poniatovii, but after the International Astronomical Union officially recognized constellations, it was placed in Ophiuchus.

Variability

File:V2391OphLightCurve.png for V2391 Ophiuchi, plotted from Hipparcos data]]

70 Ophiuchi is a variable star with a magnitude range for the two stars combined of 4.00 to 4.03. The type of variability is uncertain and it is not clear which of the two components causes the variations. It has been suspected of being either a BY Draconis variable or an RS Canum Venaticorum variable, and a period of 1.92396 days has been measured.

Binary star

The primary star is a yellow-orange main sequence dwarf of spectral type K0, while the secondary is an orange dwarf of spectral type K4. The two stars orbit each other at an average distance of 23.2 AU. But since the orbit is highly elliptical (at e=0.499), the separation between the two varies from 11.4 to 34.8 AU, with one orbit taking 88.38 years to complete.

Claims of a planetary system

In 1855, William Stephen Jacob of the Madras Observatory claimed that the orbit of the binary showed an anomaly, and it was "highly probable" that there was a "planetary body in connection with this system". This is the first known attempt to use astrometric methods to detect an exoplanet, although Friedrich Bessel had applied similar methods 10 years earlier to deduce the existence of Sirius B.

T. J. J. See made a stronger claim for the existence of a dark companion in this system in 1899, but Forest Ray Moulton soon published a paper proving that a three-body system with the specified orbital parameters would be highly unstable. The claims by Jacob and See have both been shown to be erroneous.

Discovery of a "third dark companion" was announced by Louis Berman in 1932. This "dark body" around 70 Oph A was thought to have an 18-year period and a mass of 0.1 to 0.2 the Sun's mass. A claim of a planetary system was again made, this time by Dirk Reuyl and Erik Holberg in 1943. The companion was estimated to have a mass 0.008 to 0.012 that of the Sun and a 17-year period. This caused quite a sensation at the time but later observations have gradually discredited this claim.

The negative results of past studies does not completely rule out the possibility of planets. In 2006 a McDonald Observatory team set limits to the presence of one or more planets around 70 Ophiuchi with masses between 0.46 and 12.8 Jupiter masses and average separations spanning between 0.05 and 5.2 AU.

References

{{Reflist|refs=

{{cite web |url=http://www.ianridpath.com/startales/poniatowski.html |title=Taurus Poniatovii |author=Ian Ridpath |website=Star Tales |access-date=2023-11-01 }}

{{Cite journal |last1=Boyajian |first1=Tabetha S. |last2=von Braun |first2=Kaspar |last3=van Belle |first3=Gerard |last4=McAlister |first4=Harold A. |last5=Brummelaar |first5=Theo A. ten |last6=Kane |first6=Stephen R. |last7=Muirhead |first7=Phil |last8=Jones |first8=Jeremy |last9=White |first9=Russel |last10=Schaefer |first10=Gail |last11=Ciardi |first11=David |last12=Henry |first12=Todd |last13=López-Morales |first13=Mercedes |last14=Ridgway |first14=Stephen |last15=Gies |first15=Douglas |date=2012-10-01 |title=Stellar Diameters and Temperatures II. Main Sequence K & M Stars |arxiv=1208.2431 |journal=The Astrophysical Journal |volume=757 |issue=2 |pages=112 |doi=10.1088/0004-637X/757/2/112 |bibcode=2012ApJ...757..112B |issn=0004-637X}}

{{cite journal| title=Detection Limits from the McDonald Observatory Planet Search Program | date= 7 April 2006| author=Wittenmyer | journal=The Astronomical Journal| volume= 132| issue= 1| pages= 177–188| doi= 10.1086/504942| last2=Endl| first2=Michael| last3=Cochran| first3=William D.| last4=Hatzes| first4=Artie P.| last5=Walker| first5=G. A. H.| last6=Yang| first6=S. L. S.| last7=Paulson| first7=Diane B. | bibcode=2006AJ....132..177W|arxiv = astro-ph/0604171 | s2cid= 16755455}}

{{cite journal

| title=Parallax, orbit, and mass of the binary star 70 Ophiuchi

| author=Worth, M.D.

| journal=Astrophysical Journal

| volume=193

| pages=647–650

| date=November 1974

| doi=10.1086/153202

| bibcode=1974ApJ...193..647W

| doi-access=free

}}

{{Cite journal |last1=Eggenberger |first1=P. |last2=Miglio |first2=A. |last3=Carrier |first3=F. |last4=Fernandes |first4=J. |last5=Santos |first5=N. C. |date=2008-05-01 |title=Analysis of 70 Ophiuchi AB including seismic constraints |journal=Astronomy & Astrophysics |language=en |volume=482 |issue=2 |pages=631–638 |doi=10.1051/0004-6361:20078624 |issn=0004-6361|arxiv=0802.3576 |bibcode=2008A&A...482..631E }}

{{cite journal

| title= On the Existence of a Third Component in the System 70 Ophiuchi

| author=Reuyl, Dirk

| author2=Holmberg, Erik

| journal=The Astrophysical Journal

| volume=97 | pages=41–46 |date=January 1943 | doi=10.1086/144489

| bibcode=1943ApJ....97...41R }}

{{cite journal

| title=Stars Nearer than Five Parsecs

| author=van de Kamp, Peter

| journal=Publications of the Astronomical Society of the Pacific

| volume=57

| number=334

| pages=34–41 (38*)

| date=February 1945

| doi=10.1086/125679

| bibcode=1945PASP...57...34V

| doi-access=free

}}

{{cite journal

| title= 70 Ophiuchi as a Triple System

| author=Berman, Louis

| journal=Lick Observatory Bulletin

| number=443 | pages=24–30 |date=1932 | volume=16

| doi= 10.5479/ADS/bib/1932LicOB.16.24B

| bibcode= 1932LicOB..16...24B | doi-access=free}}

{{cite journal |last=Heintz |first=W.D. |date=June 1988 |title=The Binary Star 70 Ophiuchi Revisited |journal=Journal of the Royal Astronomical Society of Canada |volume=82 |issue=3 |page=140 |bibcode=1988JRASC..82..140H }}

{{cite journal |journal=Journal for the History of Astronomy |title=A Career of controversy: the anomaly OF T. J. J. See |last=Sherrill |first=Thomas J. |date=1999 |volume=30 |doi=10.1177/002182869903000102 | pages=25–50|bibcode=1999JHA....30...25S|s2cid=117727302}}

{{cite journal |last=See |first=Thomas Jefferson Jackson |author-link=Thomas Jefferson Jackson See |date=1896 |title=Researches on the Orbit of F.70 Ophiuchi, and on a Periodic Perturbation in the Motion of the System Arising from the Action of an Unseen Body |journal=The Astronomical Journal |volume=16 |page=17 |doi=10.1086/102368 |bibcode=1896AJ.....16...17S}}

{{cite web | url=https://www.youtube.com/watch?v=2hNWCI-9n8Q | title=The First Exoplanet Claim: Captain William S Jacob| website=YouTube| date=2 December 2016}}

{{cite journal |last=Jacob |first=W.S. |date=1855 |title=On Certain Anomalies presented by the Binary Star 70 Ophiuchi |journal=Monthly Notices of the Royal Astronomical Society |volume=15 |issue=9 |pages=228–230 |url=https://books.google.com/books?id=pQsAAAAAMAAJ&q=editions:0B0EaWqbmirpeTa2sds |bibcode = 1855MNRAS..15..228J | doi = 10.1093/mnras/15.9.228|doi-access=free }}

[http://www.solstation.com/stars/70ophiu2.htm Solstation article giving details of orbital mechanics of the system]

{{cite web|url=https://vizier.cfa.harvard.edu/viz-bin/VizieR-5?-ref=VIZ62270d2f2c9e&-out.add=.&-source=J/A%2bA/544/A31/ptolema&recno=261 |title=Star Catalogue of Ptolemaios |publisher=Vizier.cfa.harvard.edu |date=2016-01-16 |accessdate=2022-03-27}}

{{cite web

| url=https://cdsarc.cds.unistra.fr/viz-bin/ftp-index?/ftp/cats/more/HIP/cdroms/cats

| website=Centre de Données astronomiques de Strasbourg | title=/ftp/cats/more/HIP/cdroms/cats

| publisher=Strasbourg astronomical Data Center | access-date=15 October 2022}}

{{Cite journal |last1=Piccotti |first1=Luca |last2=Docobo |first2=José Ángel |last3=Carini |first3=Roberta |last4=Tamazian |first4=Vakhtang S. |last5=Brocato |first5=Enzo |last6=Andrade |first6=Manuel |last7=Campo |first7=Pedro P. |date=2020-02-01 |title=A study of the physical properties of SB2s with both the visual and spectroscopic orbits |journal=Monthly Notices of the Royal Astronomical Society |volume=492 |issue=2 |pages=2709–2721 |doi=10.1093/mnras/stz3616 |doi-access=free |issn=0035-8711 |bibcode=2020MNRAS.492.2709P }} [https://vizier.cds.unistra.fr/viz-bin/VizieR?-source=J/MNRAS/492/2709&HD=165341 70 Ophiuchi's database entry] at VizieR.

{{cite journal | last1=van Leeuwen | first1=F. | title=Validation of the new Hipparcos reduction | journal=Astronomy and Astrophysics | volume=474 | issue=2 |date=November 2007 | pages=653–664 | doi=10.1051/0004-6361:20078357 | bibcode=2007A&A...474..653V | arxiv=0708.1752 | s2cid=18759600 }}

{{cite journal | last1=Morell | first1=O. | last2=Kallander | first2=D. | last3=Butcher | first3=H. R. | title=The age of the Galaxy from thorium in G dwarfs, a re-analysis | journal=Astronomy and Astrophysics | date=1999 | volume=259 | issue=2 | pages=543–548 | bibcode=1992A&A...259..543M }}

{{cite journal | display-authors=1 | last1=Maldonado | first1=J. | last2=Martínez-Arnáiz | first2=R. M. | last3=Eiroa | first3=C. | last4=Montes | first4=D. | last5=Montesinos | first5=B. | title=A spectroscopy study of nearby late-type stars, possible members of stellar kinematic groups | journal=Astronomy and Astrophysics | volume=521 | page=A12 |date=October 2010 | doi=10.1051/0004-6361/201014948 | bibcode=2010A&A...521A..12M |arxiv = 1007.1132 | s2cid=119209183 }}

{{cite web

| url=http://www.sai.msu.su/groups/cluster/gcvs/cgi-bin/search.cgi?search=V2391+Oph

| work=General Catalog of Variable Stars

| publisher=Sternberg Astronomical Institute, Moscow, Russia

| title=GCVS Query= V2391 Oph

| access-date=2018-03-08

}}

{{cite web

| url=https://www.aavso.org/vsx/index.php?view=detail.top&oid=22877

| work=International Variable Star Index

| publisher=AAVSO

| title=V2391 Oph

| access-date=2018-10-07

}}

{{cite journal|bibcode=2002A&A...384..180F|title=The Tycho double star catalogue|journal=Astronomy and Astrophysics|volume=384|pages=180–189|last1=Fabricius|first1=C.|last2=Høg|first2=E.|last3=Makarov|first3=V. V.|last4=Mason|first4=B. D.|last5=Wycoff|first5=G. L.|last6=Urban|first6=S. E.|year=2002|doi=10.1051/0004-6361:20011822|doi-access=free}}

{{cite journal|bibcode=1967AJ.....72.1334C|title=Spectral classification and photometry of high proper motion stars|journal=The Astronomical Journal|volume=72|page=1334|last1=Cowley|first1=A. P.|last2=Hiltner|first2=W. A.|last3=Witt|first3=A. N.|year=1967|doi=10.1086/110413|doi-access=free}}

{{cite journal|bibcode=2002yCat.2237....0D|title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system|journal=VizieR On-line Data Catalog|last1=Ducati|first1=J. R.|year=2002|volume=2237 }}

{{cite journal|bibcode=2000A&AS..145..215P|doi=10.1051/aas:2000237|title=Resolved double-lined spectroscopic binaries: A neglected source of hypothesis-free parallaxes and stellar masses|journal=Astronomy and Astrophysics Supplement Series|volume=145|issue=2|pages=215–222|year=2000|last1=Pourbaix|first1=D.|doi-access=free}}

{{cite journal |last1=Gore |first1=J. G. |date=March 1888 |title=On the Orbit of 70 (p) Ophiuchi |journal=Monthly Notices of the Royal Astronomical Society |volume=48 |issue= |page=257 |doi=10.1093/mnras/48.5.257 |doi-access=free |bibcode=1888MNRAS..48..257G}}

}}