| 释义 |
- References
{{Starbox begin
| name = 68 Draconis
}}{{Starbox observe
| epoch = J2000
| constell = Draco
| ra = {{RA|20|11|34.86958}}
| dec = {{DEC|+62|04|42.7575}}
| appmag_v = 5.69[3]
}}{{Starbox character
| class = F5 V[3]
| b-v = 0.48[5]
| u-b =
| variable =
}}{{Starbox astrometry
| radial_v = –14.6[6]
| prop_mo_ra = +143.276
| prop_mo_dec = +73.763
| parallax = 21.0725
| p_error = 0.0580
| parallax_footnote =
| absmag_v = 2.33[10]
}}{{Starbox detail
| mass = 1.15[11]
| radius =
| gravity = 3.95[5]
| metal_fe = 0.20[10]
| temperature = 6,137[5]
| luminosity = 10.73[15]
| rotational_velocity = 15.1[5]
| rotation =
| age_gyr = 1.7[10]
}}{{Starbox catalog
| names = {{odlist | F=68 Dra | BD=+61° 1983 | HD=192455 | HIP=99500 | HR=7727 | SAO=18751 }}[18]
}}{{Starbox reference
| Simbad=68+Dra
}}{{Starbox end}}68 Draconis is the Flamsteed designation for a star in the northern circumpolar constellation of Draco. It has an apparent visual magnitude of 5.69,[3] so, according to the Bortle scale, it is faintly visible to the naked eye from suburban skies at night. Measurements made with the Gaia spacecraft show an annual parallax shift of {{Val|0.02107|ul=arcsecond|fmt=commas}},[ which is equivalent to a distance of around {{Convert|155|ly|pc|abbr=on}} from the Sun. It is moving closer to the Earth with a heliocentric radial velocity of –14.6 km/s.[6] The star has a relatively high proper motion, traversing the celestial sphere at a rate of {{Val|0.150|u=arcsecond}} per year.[22]]The stellar classification of 68 Draconis is F5 V,[3] indicating that it is a main sequence star that is fusing hydrogen into helium at its core to generate energy. The star appears to be over-luminous for a member of its class, being 0.73 magnitudes brighter than expected. This may indicate that this is a binary system with an unresolved secondary component.[3] It has 15%[11] more mass than the Sun but is less than half as old, with an estimated age of 1.7 billion years.[10] The star is radiating 11[15] times the Sun's luminosity from its photosphere at an effective temperature of 6,137 K,[5] giving it the yellow-white hue of an F-type star.[29] References1. ^1 {{citation | last1=Lépine | first1=Sébastien | last2=Shara | first2=Michael M. | title=A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog) | journal=The Astronomical Journal | volume=129 | issue=3 | pages=1483–1522 | date=March 2005 | doi=10.1086/427854 | bibcode=2005AJ....129.1483L | arxiv=astro-ph/0412070 | postscript=. }}
2. ^1 2 {{citation | title=XHIP: An extended hipparcos compilation | last1=Anderson | first1=E. | last2=Francis | first2=Ch. | journal=Astronomy Letters | volume=38 | issue=5 | pages=331 | year=2012 | bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015 | arxiv=1108.4971 | postscript=. }}
3. ^1 2 {{citation | last1=David | first1=Trevor J. | last2=Hillenbrand | first2=Lynne A. | title=The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets | journal=The Astrophysical Journal | volume=804 | issue=2 | pages=146 | year=2015 | bibcode=2015ApJ...804..146D | arxiv=1501.03154 | doi=10.1088/0004-637X/804/2/146 | postscript=. }}
4. ^1 2 {{citation | display-authors=1 | last1=Nordström | first1=B. | last2=Mayor | first2=M. | last3=Andersen | first3=J. | last4=Holmberg | first4=J. | last5=Pont | first5=F. | last6=Jørgensen | first6=B. R. | last7=Olsen | first7=E. H. | last8=Udry | first8=S. | last9=Mowlavi | first9=N. | title=The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of ˜14,000 F and G dwarfs | journal=Astronomy and Astrophysics | volume=418 | pages=989–1019 |date=May 2004 | doi=10.1051/0004-6361:20035959 | bibcode=2004A&A...418..989N |arxiv = astro-ph/0405198 | postscript=.}}
5. ^1 2 3 4 {{citation | last1=Holmberg | first1=J. | last2=Nordström | first2=B. | last3=Andersen | first3=J. | display-authors=1 | title=The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics | journal=Astronomy and Astrophysics | volume=501 | issue=3 | pages=941–947 |date=July 2009 | doi=10.1051/0004-6361/200811191 | bibcode=2009A&A...501..941H | arxiv=0811.3982 | postscript=.}}
6. ^1 2 3 4 5 {{citation | last1=Schröder | first1=C. | last2=Reiners | first2=A. | last3=Schmitt | first3=J. H. M. M. | title=Ca II HK emission in rapidly rotating stars. Evidence for an onset of the solar-type dynamo | journal=Astronomy and Astrophysics | volume=493 | issue=3 | pages=1099–1107 |date=January 2009 | doi=10.1051/0004-6361:200810377 | bibcode=2009A&A...493.1099S | postscript=.| url=http://goedoc.uni-goettingen.de/goescholar/bitstream/handle/1/9690/aa10377-08.pdf?sequence=2}}
7. ^1 2 3 4 5 {{citation | last1=Griffin | first1=R. F. | last2=Suchkov | first2=A. A. | title=The Nature of Overluminous F Stars Observed in a Radial-Velocity Survey | journal=The Astrophysical Journal Supplement Series | volume=147 | issue=1 | pages=103–144 |date=July 2003 | doi=10.1086/367855 | bibcode=2003ApJS..147..103G | postscript=.}}
8. ^1 {{citation |title=The Colour of Stars |date=December 21, 2004 |work=Australia Telescope, Outreach and Education |publisher=Commonwealth Scientific and Industrial Research Organisation |url=http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html |accessdate=2012-01-16 |postscript=. |deadurl=yes |archiveurl=https://www.webcitation.org/6630AbtJZ?url=http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html |archivedate=March 10, 2012 }}
9. ^1 {{cite simbad | title=68 Dra | accessdate=2013-11-06 | postscript=.}}
[1][2][3][4][5][6][7][8][9]
}}{{Stars of Draco}}{{Sky|20|11|34.91|+|62|04|42.75}} 7 : F-type main-sequence stars|Draco (constellation)|Durchmusterung objects|Flamsteed objects|Henry Draper Catalogue objects|Hipparcos objects|HR objects |