Rho Ophiuchi

{{Short description|Multiple star system in the constellation Ophiuchus}} {{about|the star|the dark cloud star forming region|Rho Ophiuchi cloud complex}} {{Starbox begin | name = ρ 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=10|mark_link=Rho Ophiuchi |x=750|y=870 }} |caption=Location of ρ Ophiuchi (circled red) }} {{Starbox observe | epoch = J2000.0 | constell = Ophiuchus | ra = {{RA|16|25|35.11766}}<ref name=HIP>{{cite journal|title=Validation of the new Hipparcos reduction|author=van Leeuwen, F.|display-authors=etal|journal=Astronomy and Astrophysics|volume=474|issue=2|pages=653–664|date=2007|arxiv=0708.1752|bibcode=2007A&A...474..653V|doi=10.1051/0004-6361:20078357|s2cid=18759600}}</ref> | dec = {{DEC|-23|26|49.8150}}<ref name=HIP/> | appmag_v = 4.63<ref name=Ducati>{{Cite journal|bibcode=2002yCat.2237....0D|title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system|volume=2237|last1=Ducati|first1=J. R.|journal=VizieR Online Data Catalog|year=2002}}</ref> }} {{Starbox character | component1 = ρ Oph AB | class = B2/3V + B2V<ref>{{cite book|bibcode=1988mcts.book.....H|title=Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. Volume 4, Declinations −26°.0 to −12°.0|last1=Houk|first1=N.|last2=Smith-Moore|first2=M.|year=1988}}</ref> | b-v = +0.24<ref name=UBV>{{cite journal|title=Catalogue of homogeneous data in the UBV photoelectric photometric system|date=1964|journal=Astronomy and Astrophysics Supplement Series|volume=34|pages=1–49|author=Nicolet, B.|bibcode=1978A&AS...34....1N}}</ref> | u-b = −0.56<ref name=UBV/> | variable = }} {{Starbox astrometry | component1 = ρ Oph AB | radial_v = {{val|−14.6|1.5}}<ref name=Klement2025/> | prop_mo_ra = −5.53 | prop_mo_dec = −21.74 | pm_footnote = <ref name=HIP/> | parallax = 7.19 | p_error = 0.13 | parallax_footnote = <ref name=Shultz2025/> | dist_pc = {{Val|138.2|3.6}} | dist_ly = {{val|{{convert|138.2|pc|ly|disp=number}}|{{convert|3.6|pc|ly|disp=number}}|fmt=commas}} | dist_footnote = <ref name=Klement2025/> | absmag_v = {{val|-2.5|0.3}}<ref name=Wegner>{{cite journal|bibcode=2003AN....324..219W|doi=10.1002/asna.200310081|title=The total-to-selective extinction ratio determined from near IR photometry of OB stars|journal=Astronomische Nachrichten|volume=324|issue=3|pages=219–237|year=2003|last1=Wegner|first1=W.}}</ref> }} {{Starbox orbit | primary = ρ Oph Aa | name = ρ Oph Ab | reference = <ref name=Klement2025>{{Cite journal |last=Klement |first=R. |last2=Shultz |first2=M. E. |last3=Rivinius |first3=Th |date=2025-06-01 |title=Spatially resolved centrifugal magnetosphere caught in motion around the secondary component of ρ Oph A |journal=Astronomy & Astrophysics |language=en |volume=699 |pages=A37 |doi=10.1051/0004-6361/202554689 |doi-access=free |arxiv=2505.08007 |issn=0004-6361}}</ref> | period_unitless = {{Val|87.831|0.010}} days | axis_unitless = {{Val|0.995|0.026|ul=AU}} | eccentricity = {{Val|0.17931|0.00017}} | inclination = {{val|71.348|0.020}} | k1 = {{Val|55.5|3.6}} | k2 = {{Val|65.7|3.6}} | periarg = {{Val|4.80|0.24}} | node = {{Val|303.385|0.034}} | periastron = 60101.11 RJD }} {{Starbox orbit | reference = <ref name=Novakovic>{{cite journal|title=Orbits of Five Visual Binary Stars|author=Novaković, B.|journal=Baltic Astronomy|volume=16|pages=435–442|date=2007|bibcode=2007BaltA..16..435N|arxiv=0712.4242}}</ref> | primary = ρ Oph A | name = ρ Oph B | period_unitless = {{val|2398|326|fmt=commas}} years | axis = {{val|4.25|0.79}} | eccentricity = {{val|0.675|0.322}} | inclination = {{val|135.3|6.0}} | node = {{val|77.5|13.5}} | periastron = B {{val|2327|343}} | periarg = {{val|226.1|15.3}} }} {{Starbox orbit | reference = <ref name=Novakovic/> | primary = ρ Oph D | name = ρ Oph E | period_unitless = {{val|675.5|32.5}} years | axis = {{val|1.01|0.15}} | eccentricity = {{val|0.707|0.112}} | inclination = {{val|134.8|2.7}} | node = {{val|152.7|4.6}} | periastron = B {{val|2008.6|34.2}} | periarg = {{val|260.4|1.1}} }} {{Starbox detail | source = <ref name=Shultz2025/> | component1 = ρ Oph Aa | mass = {{Val|9.21|0.79}}<ref name=Klement2025/> | radius = {{val|4.2|0.3}} | rotation = 1.205<ref name=Hubrig/> days | rotational_velocity = {{val|206|5}} | luminosity = {{Val|4270|980|800|fmt=commas}} | temperature = {{Val|23000|1000|fmt=commas}} | gravity = {{Val|4.25|0.25}} | age_myr = {{Val|15|6}} | component2 = ρ Oph Ab | mass2 = {{Val|7.79|0.70}}<ref name=Klement2025/> | radius2 = {{Val|3.1|0.2}} | luminosity2 = {{val|1000|400|290|fmt=commas}} | temperature2 = {{val|19000|1000|fmt=commas}} | gravity2 = {{Val|4.25|0.25}} | age_myr2 = {{Val|15|6}} | rotational_velocity2 = {{val|227|5}} }} {{Starbox detail | no_heading = y | component1 = ρ Oph B | mass = 8<ref name=Allen>{{cite journal|doi=10.1093/mnras/sty2502|title=The dynamical evolution of multiple systems of trapezium type|year=2018|last1=Allen|first1=Christine|author1-link=Christine Allen (astronomer)|last2=Ruelas-Mayorga|first2=Alex|last3=Sánchez|first3=Leonardo J.|last4=Costero|first4=Rafael|journal=Monthly Notices of the Royal Astronomical Society|doi-access=free|arxiv=1809.03537}}</ref> }} {{Starbox detail | no_heading = y | component1 = ρ Oph C | mass = 5<ref name=Allen/> }} {{Starbox detail | no_heading = y | component1 = ρ Oph D | mass = 3.06<ref name=Novakovic/> | component2 = ρ Oph E | mass2 = 1.97<ref name=Novakovic/> }} {{Starbox catalog | names = {{odlist|B=ρ Oph|F=5 Oph|WDS=J16256-2327}} | component1=ρ Oph AB | names1={{odlist|HIP=80473|CD=-23°12861}} | component2=ρ Oph A | names2={{odlist|HD=147933|HR=6112|SAO=184382}} | component3=ρ Oph B | names3={{odlist|HD=147934|HR=6113|SAO=184381}} | component4=ρ Oph C | names4={{odlist|HIP=80474|SAO=184383|CD=-23°12862}} | component5=ρ Oph D/E | names5={{odlist|HD=147888|HIP=80461|SAO=184377|CD=-23°12860}} }} {{Starbox reference | Simbad=rho+Oph|sn=ρ Oph | Simbad2=HD+147933|sn2=ρ Oph A | Simbad3=HD+147934|sn3=ρ Oph B | Simbad4=HD+147932|sn4=ρ Oph C | Simbad5=HD+147888|sn5=ρ Oph D/E }} {{Starbox end}} '''Rho Ophiuchi (ρ Ophiuchi)''' is a multiple star system in the constellation Ophiuchus. The central system has an apparent magnitude of 4.63.<ref name=Ducati/> Based on the central system's parallax, it is located about 450 light-years distant.<ref name=Klement2025/> The other stars in the system are slightly farther away.<ref name=Cordiner/>{{clarify|reason=Slightly further away in distance from Earth or distance from the inner pair?|date=May 2025}}

==System== [[File:Antares_and_Rho_Ophiuchi_by_Adam_Block.jpg|thumb|left|Rho Ophiuchi cloud complex (N is up): Antares is the bright star that looks yellow in this image, σ Scorpii is in the red nebula (Sh2-9), and the globular cluster M4 is in between. Rho Ophiuchi is the small group of stars in the blue nebulosity (IC 4604).]] The central system is known as Rho Ophiuchi AB. It consists of three blue-colored subgiants or main-sequence stars, designated Rho Ophiuchi Aa, Ab and B, respectively.<ref name=Cordiner/> Rho Ophiuchi A is a spectroscopic binary with an orbital period of 88 days and an orbital separation of 1.1 astronomical units.<ref name=Shultz2025>{{Cite journal |last=Shultz |first=M. E. |last2=Berry |first2=I. |last3=Bohlender |first3=D. |last4=Catanzaro |first4=G. |last5=Giarrusso |first5=M. |last6=Klement |first6=R. |last7=Labadie-Bartz |first7=J. |last8=Leone |first8=F. |last9=Leto |first9=P. |last10=Neiner |first10=C. |last11=Owocki |first11=S. P. |last12=Rivinius |first12=Th |last13=ud-Doula |first13=A. |last14=Wade |first14=G. A. |date=2025-08-01 |title=Discovery of the binary nature of the magnetospheric B-type star ρ Oph A |journal=Astronomy & Astrophysics |language=en |volume=700 |pages=A14 |doi=10.1051/0004-6361/202554023 |doi-access=free |arxiv=2505.08007 |issn=0004-6361}}</ref> Farther away is the B companion, a visual binary whose sky-projected distance from the inner pair appears to be 3.1″, corresponding to a separation of at least 344 AU.<ref name=Cordiner>{{Cite journal|bibcode=2013ApJ...764L..10C|title=Cordiner, M. A., Fossey, S. J., Smith, A. M. and Sarre, P. J. 2013, ApJ, 764, L10|journal=The Astrophysical Journal Letters|volume=764|pages=L10|last1=Cordiner|first1=M. A.|last2=Fossey|first2=S. J.|last3=Smith|first3=A. M.|last4=Sarre|first4=P. J.|year=2013|issue=1|doi=10.1088/2041-8205/764/1/L10|arxiv = 1301.6167 |s2cid=119204101|url=https://zenodo.org/record/897951}}</ref> However, the actual separation is larger, and the two take about 2,400 years to complete an orbit.<ref name=Novakovic/> The two stars dominate the radiation field around the Rho Ophiuchi cloud complex.<ref name=Hubrig>{{cite journal|doi=10.1002/asna.201713457|title=Detection of a centrifugal magnetosphere in one of the most massive stars in the ρ Oph star-forming cloud|year=2018|last1=Hubrig|first1=S.|last2=Schöller|first2=M.|last3=Järvinen|first3=S. P.|last4=Küker|first4=M.|last5=Kholtygin|first5=A. F.|last6=Steinbrunner|first6=P.|journal=Astronomische Nachrichten|volume=339|issue=1|pages=72–77|arxiv=1712.05939|bibcode=2018AN....339...72H|s2cid=119084902}}</ref>

Rho Ophiuchi A emits weak X-rays due to the strong magnetic field of the secondary companion, Rho Ophiuchi Ab, whose dipole strength is 4 kG.<ref name=Shultz2025/><ref>{{cite arxiv|last=Gunderson |first=Sean J. |last2=Codd |first2=Jackson |last3=Golay |first3=Walter W. |last4=Huenemoerder |first4=David P. |last5=Cannon |first5=John M. |last6=Fluegel |first6=J. Alex |last7=Griffin |first7=Philip E. |last8=Haurberg |first8=Nathalie C. |last9=Ignace |first9=Richard |title=A Multiwavelength View of ρ Oph I: Resolving the X-ray Source Between A and B |date=2025-09-30 |arxiv=2509.26268 |class=astro-ph.SR}}</ref> Rho Ophiuchi B also emits X-rays at an intensity much higher than the expected for a B2V-type star, and appear to show flares on its light curve and spectrum, suggesting it may be an Algol-type system with a K-type companion.<ref>{{cite arxiv|last=Gunderson |first=Sean J. |last2=Codd |first2=Jackson |last3=Golay |first3=Walter W. |last4=Huenemoerder |first4=David P. |last5=Cannon |first5=John M. |last6=Fluegel |first6=J. Alex |last7=Griffin |first7=Philip E. |last8=Haurberg |first8=Nathalie C. |last9=Ignace |first9=Richard |title=A Multiwavelength View of ρ Oph I: Resolving the X-ray Source Between A and B |date=2025-09-30 |arxiv=2509.26268 |class=astro-ph.SR}}</ref>

Several other stars are located close to Rho Ophiuchi AB. HD 147932 is located 2.5 arcminutes away (at least 17,000 AU), and is known as Rho Ophiuchi C.<ref name=Cordiner/> HD 147888 is located 2.82 arcminutes away (at least 19,000 AU), and is known as Rho Ophiuchi DE.<ref name=Cordiner/> Stars C and D are both B-type main-sequence stars,<ref name=Cordiner/> and D itself is another binary with an orbital period of around 680 years.<ref name=Novakovic/>

==Cloud complex== {{main|Rho Ophiuchi cloud complex}} Rho Ophiuchi is the namesake of the Rho Ophiuchi cloud complex. It is a nebula of gas and dust, which the Rho Ophiuchi system is embedded in. It is one of the easiest star forming regions to observe, as it is one of the nearest, and it is visible from both hemispheres.<ref>{{cite journal|bibcode=2008hsf2.book..351W|arxiv=0811.0005|title=Star Formation in the ρ Ophiuchi Molecular Cloud|author1=Wilking, B. A.|author2=Gagné, M.|author3=Allen, L. E.|author3-link=Lori Allen (astronomer)|journal=Handbook of Star Forming Regions|date=2008}}</ref>

The interstellar extinction (A<sub>''V''</sub>) of Rho Ophiuchi is measured to be 1.45 magnitudes, meaning the dust and gas in front of Rho Ophiuchi absorbs light from the system, making it appear 1.45 magnitudes dimmer than it would be if there were no dust or gas.<ref name=Shatsky>{{cite journal|title=The mass ratio distribution of B-type visual binaries in the Sco OB2 association|author1=Shatsky, N.|author2=Tokovinin, A.|journal=Astronomy and Astrophysics|volume=382|pages=92–103|date=2002|bibcode=2002A&A...382...92S|doi=10.1051/0004-6361:20011542|arxiv=astro-ph/0109456|s2cid=16697655}}</ref> Additionally, gas and dust also scatters more higher-frequency light, leaving the light appearing more reddish. The interstellar reddening (''E<sub>B−V</sub>'') of Rho Ophiuchi has been measured to be 0.47 magnitudes.<ref name=Wegner/> {{clear left}} ==References== {{reflist}}

Category:Ophiuchus 5 Category:B-type main-sequence stars Ophiuchi, Rho Ophiuchi, 05 Category:Durchmusterung objects 147933 080473 6112