HD 196775

{{Starbox begin

| name = HD 196775

}}

{{Starbox observe

| epoch = J2000.0 (ICRS)

| constell = Delphinus

| ra = {{RA|20|39|04.9681}}

| dec = {{DEC|+15|50|17.5112}}

| appmag_v = 5.98

}}

{{Starbox character

| class = B3 V

| b-v = −0.16

| u-b = −0.71

}}

{{Starbox astrometry

| radial_v = −4.6{{±|1}}

| parallax = 3.1211

| p_error = 0.0617

| parallax_footnote =

| prop_mo_ra = −0.868

| prop_mo_dec = −15.290

| pm_footnote =

| absmag_v = −2.05

}}

{{Starbox detail

| mass = 7{{±|0.4}}

| radius = 4.13{{±|0.14}}

| luminosity = 1,507

| gravity = 3.97

| metal_fe =

| temperature = 18,100

| rotational_velocity = 145{{±|6}}

| age_myr = 36.1{{±|9.5}}

}}

{{Starbox catalog

| names = {{odlist|HD = 196775|HIP = 101909|BD = +15°4220|AG = +15°2265|GC = 28785|HR = 7899|WDS = J20391+1550A|SAO = 106347}}

}}

{{Starbox reference

| Simbad = HR+7899

}}

HD 196775 (HR 7899) is a solitary star in the equatorial constellation Delphinus. It has an apparent magnitude of 5.98, allowing it to be faintly seen with the naked eye. The object is relatively far at a distance of 1,050 light years but is approaching the Solar System with a heliocentric radial velocity of {{val|-4.6|ul=km/s}}. HD 196775 has a high peculiar velocity of {{val|21.8|1.9|4.1|ul=km/s}} compared to neighboring stars, indicating that it may be a runaway star.

HD 196775 has a general stellar classification of B3 V, indicating that it is an ordinary B-type main-sequence star. However, once source gives it a class of B4 Vn, making it slightly cooler and having broad absorption lines due to rapid rotation. It has an angular diameter of {{val|0.12|ul=mas}}, yielding a radius 4.13 times that of the Sun. At present it has 7 times the mass of the Sun and shines at {{val|1,507|ul=solar luminosity}} from its photosphere at an effective temperature of {{val|18,100|ul=K|fmt=commas}}, giving it a whitish blue hue. HD 196775 is 36 million years old and is spinning rapidly with a projected rotational velocity of {{val|145|ul=km/s}}.

HD 196775 has four faint optical companions whose parameters are listed below.

class="wikitable"

|+HD 196775's Companions

!Companion

!m_v

!PA (°)

!Year

!Sep. (″)

|12.40

|154

|2006

|5.2

|11.31

|122

|2012

|39.9

|14.40

|146

|2012

|28.8

|14.40

|33

|2012

|23.3

References

{{reflist||refs=

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{{cite journal | last1=Bragança | first1=G. A. | last2=Daflon | first2=S. | last3=Cunha | first3=K. | last4=Bensby | first4=T. | last5=Oey | first5=M. S. | last6=Walth | first6=G. | title=Projected Rotational Velocities and Stellar Characterization of 350 B Stars in the Nearby Galactic Disk | journal=The Astronomical Journal | publisher=American Astronomical Society | volume=144 | issue=5 | date=October 1, 2012 | issn=0004-6256 | doi=10.1088/0004-6256/144/5/130 | page=130 |bibcode = 2012AJ....144..130B |arxiv = 1208.1674 |doi-access = free}}

{{cite book | first1=Kenneth R. | last1=Lang | title=Astrophysical formulae | volume=1 | series=Astronomy and astrophysics library | edition=3 | publisher=Birkhäuser | year=2006 | isbn=3-540-29692-1 | url=https://books.google.com/books?id=OvTjLcQ4MCQC&pg=PA41 }}. The radius (R_*) is given by:

: $\begin{align} 2\cdot R_*
& = \frac{(320\cdot 0.12\cdot 10^{-3})\ \text{AU}}{0.0046491\ \text{AU}/R_{\bigodot}} \\
& \approx 8.26\cdot R_{\bigodot}
\end{align}$

{{cite journal |last1=McDonald |first1=I. |last2=Zijlstra |first2=A. A. |last3=Boyer |first3=M. L. |title=Fundamental parameters and infrared excesses of Hipparcos stars: Parameters and IR excesses from Hipparcos |journal=Monthly Notices of the Royal Astronomical Society |date=21 November 2012 |volume=427 |issue=1 |pages=343–357 |doi=10.1111/j.1365-2966.2012.21873.x |issn=0035-8711 |bibcode=2012MNRAS.427..343M |arxiv=1208.2037 |doi-access=free}}

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{{cite journal|last1=Bourgés |first1=L. |last2=Lafrasse |first2=S. |last3=Mella |first3=G. |last4=Chesneau |first4=O. |last5=Bouquin |first5=J. L. |last6=Duvert |first6=G. |last7=Chelli |first7=A. |last8=Delfosse |first8=X. |title=The JMMC Stellar Diameters Catalog v2 (JSDC): A New Release Based on SearchCal Improvements |journal=Astronomical Data Analysis Software and Systems Xxiii |date=May 2014 |volume=485 |pages=223 |bibcode=2014ASPC..485..223B}}

{{cite journal | last=de Vaucouleurs | first=A. | title=Spectral Types and Luminosities of B, A and F Southern Stars | journal=Monthly Notices of the Royal Astronomical Society | publisher=Oxford University Press (OUP) | volume=117 | issue=4 | date=August 1, 1957 | issn=0035-8711 | doi=10.1093/mnras/117.4.449 | pages=449–462 |bibcode =1957MNRAS.117..449D| doi-access=free }}

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}}

Category:Delphinus

Category:B-type main-sequence stars

Category:Runaway stars