{{Short description|Star in the constellation Draco}} {{Starbox begin}} {{Starbox image | image = {{Location mark |image=Draco constellation map.svg|alt=|float=center|width=280 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=HD 175535 |x=10|y=882 }} | caption = Location of HD 175535 (circled in red) }} {{Starbox observe | epoch = J2000 | constell = [[Draco (constellation)|Draco]]<ref name=Anderson2012/> | ra = {{RA|18|53|13.55099}}<ref name=GaiaDR3/> | dec = {{DEC|+50|42|29.5940}}<ref name=GaiaDR3/> | appmag_v = 4.92<ref name=Luck2015/> }} {{Starbox character | type = [[red giant branch]]<ref Name=GaiaDR3/> | class = {{nowrap|G7 IIIa Fe−1}}<ref name=perkins1989/> | b-v = 0.90<ref name=Luck2015/> | u-b = 0.57<ref name=Griffin2010/> }} {{Starbox astrometry | radial_v = +8.5<ref name=Luck2015/> | prop_mo_ra = −4.442<ref name=GaiaDR3/> | prop_mo_dec = −21.985<ref name=GaiaDR3/> | parallax = 11.1969 | p_error = 0.4974 | parallax_footnote = <ref name=GaiaDR3/> | absmag_v = −0.78<ref name=Anderson2012/> }} {{Starbox orbit | reference = <ref name=Griffin2010/> | period_unitless = {{Val|972.84|0.35|u=days}} | eccentricity = {{Val|0.342|0.006}} | periastron = {{Val|53678.2|2.4|fmt=commas}} | periarg = {{Val|190.0|1.1}} | k1 = {{Val|5.83|0.04}} }} {{Starbox detail | source = | mass = 3.27<ref name=Luck2015/> | radius = 13<ref name=Cadars2001/> | luminosity = 219<ref name=Luck2015/> | gravity = {{Val|2.85|0.15}}<ref name=prugniel2011/> | temperature = {{Val|5024|74|fmt=commas}}<ref name=Luck2015/> | metal_fe = {{Val|−0.07|0.07}}<ref name=prugniel2011/> | rotational_velocity = 2.3<ref name=DeMedeiros2002/> | age_myr = 320<ref name=Luck2015/> }} {{Starbox catalog | names = {{odlist | BD=+50°2686 | FK5= | GJ= | HD=175535 | HIP=92689 | HR=7137 | SAO=31241 }}<ref name=SIMBAD/> }} {{Starbox reference | Simbad = HD+175535 }} {{Starbox end}}

'''HD 175535''' is a [[binary star]] system in the northern [[circumpolar constellation]] of [[Draco (constellation)|Draco]]. It has an [[apparent visual magnitude]] of 4.92,<ref name=Luck2015/> which is bright enough to be faintly visible to the naked eye. The system is located about 290&nbsp;[[light year]]s away, as determined from its annual [[stellar parallax|parallax shift]] of {{Val|11.2|ul=mas}}.<ref name=GaiaDR3/> It is moving further from the Earth with a heliocentric [[radial velocity]] of +8.5&nbsp;km/s.<ref name=Luck2015/>

The binary nature of this system was announced by [[W. W. Campbell]] of the [[Lick Observatory]] in 1911. It is a single-lined [[spectroscopic binary]] with an [[orbital period]] of {{Convert|972.84|day|year|order=flip|sigfig=3}} and an [[orbital eccentricity|eccentricity]] of 0.342. The {{nowrap|''a'' sin ''i''}} value for the visible component is {{Val|73.4|0.6|ul=Gm}}, where ''a'' is the [[semimajor axis]] and ''i'' is the (unknown) [[orbital inclination]].<ref name=Griffin2010/> This indicates that the actual semimajor axis is larger than {{Convert|73.4|Gm|AU|lk=on|sigfig=2|disp=out}}.<ref>The maximum value of the [[sine]] function is 1.0; hence, 'a' is no smaller than the value cited.</ref>

The visible component appears to be an [[stellar evolution|evolved]] [[giant star]] with a [[stellar classification]] of {{nowrap|G7 IIIa Fe−1}},<ref name=perkins1989/> where the suffix notation indicates an underabundance of iron in the [[stellar atmosphere|atmosphere]]. It is 320<ref name=Luck2015/> million years old with 3.27<ref name=Luck2015/> times the [[mass of the Sun]] and about 13<ref name=Cadars2001/> times the [[Sun's radius]]. The star is radiating 219<ref name=Luck2015/> times the [[Sun's luminosity]] from its enlarged [[photosphere]] at an [[effective temperature]] of 5,024&nbsp;K.<ref name=Luck2015/>

==References== <references> <ref name=SIMBAD>{{cite simbad | title=HD 175535 | access-date=2018-07-19 }}</ref>

<ref name=GaiaDR3>{{cite Gaia DR3|2144423264761182848}}</ref>

<ref name=Anderson2012>{{cite XHIP|92689}}</ref>

<ref name=Luck2015>{{citation | title=Abundances in the Local Region. I. G and K Giants | last1=Luck | first1=R. Earle | journal=Astronomical Journal | postscript=. | volume=150 | issue=3 | at=88 | year=2015 | bibcode=2015AJ....150...88L | doi=10.1088/0004-6256/150/3/88 |arxiv = 1507.01466 | s2cid=118505114 }}</ref>

<ref name=prugniel2011>{{citation | title=The atmospheric parameters and spectral interpolator for the MILES stars | journal=Astronomy & Astrophysics | postscript=. | volume=531| pages=A165| year=2011 | display-authors=1 | last1=Prugniel | first1=P. | last2=Vauglin | first2=I.| last3=Koleva | first3=M. | doi=10.1051/0004-6361/201116769 | arxiv=1104.4952 | bibcode=2011A&A...531A.165P | s2cid=54940439 }}</ref>

<ref name=Griffin2010>{{citation | title=Spectroscopic binary orbits from photoelectric radial velocities - Paper 214: HR 6790, HR 6886, HR 6901, and HR 7137 | last1=Griffin | first1=R. F. | journal=The Observatory | volume=130 | pages=299–314 | date=October 2010 | bibcode=2010Obs...130..299G | postscript=. }}</ref>

<ref name=perkins1989>{{citation | title=The Perkins catalog of revised MK types for the cooler stars | journal=Astrophysical Journal Supplement Series | last1=Keenan | first1=Philip C. | last2=McNeil | first2=Raymond C. | volume=71 | pages=245 | year=1989 | bibcode=1989ApJS...71..245K | doi=10.1086/191373 }}</ref>

<ref name=DeMedeiros2002>{{citation | title=The Rotation of Binary Systems with Evolved Components | display-authors=1 | last1=De Medeiros | first1=J. R. | last2=Da Silva | first2=J. R. P. | last3=Maia | first3=M. R. G. | journal=The Astrophysical Journal | postscript=. | volume=578 | issue=2 | pages=943–950 | date=October 2002 | doi=10.1086/342613 | bibcode=2002ApJ...578..943D | arxiv=astro-ph/0207288| s2cid=16196039 }}</ref>

<ref name=Cadars2001>{{citation | last1=Pasinetti Fracassini | first1=L. E. | last2=Pastori | first2=L. | last3=Covino | first3=S. | last4=Pozzi | first4=A. | title=Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition | journal=Astronomy and Astrophysics | volume=367 | issue=2 | pages=521–524 | date=February 2001 | bibcode=2001A&A...367..521P | doi=10.1051/0004-6361:20000451 | arxiv=astro-ph/0012289 | s2cid=425754 | postscript=. }}</ref> </references>

{{Stars of Draco}}

[[Category:G-type giants]] [[Category:Spectroscopic binaries]] [[Category:Draco (constellation)]] [[Category:Durchmusterung objects|BD+50 2686]] [[Category:Henry Draper Catalogue objects|175535]] [[Category:Hipparcos objects|092689]] [[Category:Bright Star Catalogue objects|7137]]