GD 165
{{Short description|Star in the constellation Boötes}}
{{Cleanup|date=February 2017|reason=the article looks messy, and does not have much text}}
{{Sky|14|24|39.144|+|09|17|13.98|102.9}}
{{Starbox begin}}
{{Starbox image
|image=230px
|caption=The white dwarf GD 165 A is seen in the center of the image as a bright star. The brown dwarf GD 165 B is below the white dwarf, seen as a red spot.
}}
{{Starbox observe
|epoch=J2000{{r|Simbad}}
|equinox=J2000{{r|Simbad}}
|constell=Boötes
|ra={{RA|14|24|39.144}}{{r|Simbad}}
|dec={{DEC|09|17|13.98}}{{r|Simbad}}
}}
{{Starbox character
| type=white dwarf + brown dwarf
| class=DA4{{r|Kirkpatrick1997}}+L4{{r|Kirkpatrick1999}}
}}
{{Starbox astrometry
| prop_mo_dec=−149.648 ± 0.074
| parallax=29.9335
| p_error=0.0559
}}
{{Starbox detail
| component1=GD 165 A
| component2=GD 165 B
| luminosity2=
}}
{{Starbox catalog
|names=CX Boo, LSPM J1424+0917, 2MASS J14243914+0917139, WDS J14247+0917A, WD 1422+095
}}
{{Starbox reference
|Simbad=GD+165|sn=GD 165 A
|Simbad2=GD+165+B|sn2=GD 165 B
}}
{{Starbox end}}
GD 165 is a binary white dwarf and brown dwarf system located in the Boötes constellation, roughly 109 light-years from Earth.{{Cite journal |last1=Kirkpatrick |first1=J. Davy |authorlink1=J. Davy Kirkpatrick |last2=Allard |first2=France |last3=Bida |first3=Tom |last4=Zuckerman |first4=Ben |last5=Becklin |first5=E. E. |last6=Chabrier |first6=Gilles |last7=Baraffe |first7=Isabelle |authorlink7=Isabelle Baraffe |date=July 1999 |title=An Improved Optical Spectrum and New Model FITS of the Likely Brown Dwarf GD 165B |journal=Astrophysical Journal |language=en |volume=519 |issue=2 |pages=834–843 |bibcode=1999ApJ...519..834K |doi=10.1086/307380 |issn=0004-637X |doi-access=free}} Neither of the stars have any known exoplanets.
Nomenclature and observation
The system GD 165 is named after Henry L. Giclas, an American Astronomer who lived throughout the 20th century.{{r|GD}}
In 1990, GD 165 A was discovered to be a variable star by Pierre Bergeron and John Thomas McGraw. It was given its variable star designation, CX Boötes, in 1993.
GD 165 B was discovered in 1988 by Eric Becklin and Benjamin Zuckerman at the University of California, Los Angeles.{{r|Becklin1988}} GD 165 B was the first brown dwarf discovered to be cooler than M-Type stars{{r|Dahn2002}} and was initially assigned the spectral type ≥M10. It would not be regarded as a brown dwarf until 1999, when new spectral types L-Type and T-Type for objects cooler than M-type stars were established, reclassifying GD 165 B as L4.{{r|Kirkpatrick1999}}
Physical properties
GD 165 A is a pulsating white dwarf with a temperature of about 12,100 K, a mass of 0.64 {{Solar mass}}, and a radius of 0.0124 {{Solar radius}}.{{Cite journal|last1=Giammichele|first1=N.|last2=Fontaine|first2=G.|last3=Brassard|first3=P.|last4=Charpinet|first4=S.|date=March 2016|title=A New Analysis of the Two Classical ZZ Ceti White Dwarfs GD 165 and Ross 548. II. Seismic Modeling|journal=Astrophysical Journal Supplement Series|language=en|volume=223|issue=1|pages=10|doi=10.3847/0067-0049/223/1/10|issn=0067-0049|bibcode=2016ApJS..223...10G|s2cid=124354534 |doi-access=free }} GD 165 A has an extremely dim luminosity of 0.0030{{Solar luminosity}}, making it completely invisible to the naked eye.
File:GD165LightCurve.png for GD 165, adapted from Giammichele et al. (2015)]]
GD 165 B is an L-Type brown dwarf with a temperature of about 1,750 K, a mass of about 63 {{Jupiter mass|link=true}}, and a radius of 1.00 {{Jupiter radius}}. GD 165B is separated by 123±12 astronomical units from its host white dwarf. It is the second closest spacially resolved brown dwarf after PHL 5038, which has a separation of around 69 AU.{{Cite journal |last1=French |first1=Jenni R. |last2=Casewell |first2=Sarah L. |last3=Dupuy |first3=Trent J. |last4=Debes |first4=John H. |last5=Manjavacas |first5=Elena |last6=Martin |first6=Emily C. |last7=Xu |first7=Siyi |date=2023-03-01 |title=Discovery of a resolved white dwarf-brown dwarf binary with a small projected separation: SDSS J222551.65+001637.7AB |url=https://academic.oup.com/mnras/article/519/4/5008/6972383 |journal=Monthly Notices of the Royal Astronomical Society |volume=519 |issue=4 |pages=5008–5016 |arxiv=2301.02101 |bibcode=2023MNRAS.519.5008F |doi=10.1093/mnras/stac3807 |doi-access=free |issn=0035-8711}} It produces almost no light and is completely invisible to the naked eye.
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See also
Other cooler than M brown dwarfs, discovered before 1998:
- Gliese 229 B – T6.5{{r|Burgasser2002}}{{r|Nakajima1995}}
- 2MASP J0345432+254023 – L0 (first isolated L-dwarf){{r|Kirkpatrick1999}}
- DENIS-P J020529.0-115925 – L7{{r|Kirkpatrick1999}}{{r|Delfosse1997}}
- DENIS-P J1058.7-1548 – L3{{r|Kirkpatrick1999}} {{r|Delfosse1997}}
- DENIS-P J1228.2-1547 – L5{{r|Kirkpatrick1999}}{{r|Delfosse1997}}
- Kelu-1 – L2{{r|Kirkpatrick1999}}{{r|Ruiz1997}}
References
{{reflist|colwidth=30em|refs=
| url=http://simbad.u-strasbg.fr/simbad/sim-id?Ident=GD+165
| title=V* CX Boo – Pulsating White Dwarf
| work=SIMBAD
| publisher=Centre de Données astronomiques de Strasbourg
| access-date=2013-09-23}}
{{cite journal |last1=Becklin |first1=E. E. |last2=Zuckerman |first2=B. |s2cid=4358564 |title=A low-temperature companion to a white dwarf star |year=1988 |journal=Nature |volume=336 | issue=Dec. 15, 1988 | pages=656–658 |doi=10.1038/336656a0 |bibcode=1988Natur.336..656B}}
{{cite journal |last=Nakajima |first=T. |author2=Oppenheimer, B. R. |author3=Kulkarni, S. R. |author4=Golimowski, D. A. |author5=Matthews, K. |author6=Durrance, S. T. |author7=Neto, D. N. |author8=Teixeira, R. |s2cid=4351772 |title=Discovery of a cool brown dwarf |year=1995 |journal=Nature |volume=378 | issue=6556 | pages=463–465 |doi=10.1038/378463a0 |bibcode=1995Natur.378..463N}}
{{cite journal |author-link=J. Davy Kirkpatrick |last=Kirkpatrick |first=J. Davy |author2=Beichman, Charles A. |author3=Skrutskie, Michael F. |title=The Coolest Isolated M Dwarf and Other 2MASS Discoveries |year=1997 |journal=The Astrophysical Journal |volume=476 |issue=1 |pages=311–318 |doi=10.1086/303613 |bibcode=1997ApJ...476..311K |doi-access=free }}
{{cite journal |bibcode=1997A&A...327L..25D |last1=Delfosse |first1=Xavier |last2=Tinney |first2=Chris G. |last3=Forveille |first3=Thierry |last4=Epchtein |first4=Nicolas |last5=Bertin |first5=Emmanuel |last6=Borsenberger |first6=Jean |last7=Copet |first7=Éric |last8=de Batz |first8=Bertrand |last9=Fouqué |first9=Pascal |last10=Kimeswenger |first10=Stefan |last11=Le Bertre |first11=Thibaut |last12=Lacombe |first12=François |last13=Rouan |first13=Daniel |last14=Tiphène |first14=Didier |title=Field brown dwarfs found by DENIS |year=1997 |journal=Astronomy and Astrophysics |volume=327 |pages=L25–L28 }}
{{cite journal |last=Ruiz |first=Maria Teresa |author2=Leggett, S. K. |author3=Allard, France |title=Kelu-1: A Free-floating Brown Dwarf in the Solar Neighborhood |year=1997 |journal=The Astrophysical Journal Letters |volume=491 |issue=2 | pages=L107–L110 |doi=10.1086/311070 |bibcode=1997ApJ...491L.107R|doi-access=free }}
{{cite journal |doi=10.1086/307414 |last1=Kirkpatrick |first1=J. Davy |last2=Reid |first2=I. Neill |last3=Liebert |first3=James |last4=Cutri |first4=Roc M. |last5=Nelson |first5=Brant |last6=Beichman |first6=Charles A. |last7=Dahn |first7=Conard C. |last8=Monet |first8=David G. |last9=Gizis |first9=John E. |last10=Skrutskie |first10=Michael F. |title=Dwarfs Cooler than "M": The Definition of Spectral Type "L" Using Discoveries from the 2 Micron All-Sky Survey (2MASS) |year=1999 |journal=The Astrophysical Journal |volume=519 |issue=2 |pages=802–833 |bibcode=1999ApJ...519..802K |s2cid=73569208 |url=https://trs.jpl.nasa.gov/bitstream/2014/37403/1/99-0060.pdf }}
{{cite journal |last1=Burgasser |first1=Adam J. |last2=Kirkpatrick |first2=J. Davy |author-link2=J. Davy Kirkpatrick |last3=Brown |first3=Michael E. |author-link3=Michael E. Brown |last4=Reid |first4=I. Neill |last5=Burrows |first5=Adam |last6=Liebert |first6=James |last7=Matthews |first7=Keith |last8=Gizis |first8=John E. |last9=Dahn |first9=Conard C. |last10=Monet |first10=David G. |last11=Cutri |first11=Roc M. |last12=Skrutskie |first12=Michael F. |title=The Spectra of T Dwarfs. I. Near-Infrared Data and Spectral Classification |year=2002 |journal=The Astrophysical Journal |volume=564 |issue=1 |pages=421–451 |arxiv=astro-ph/0108452 |doi=10.1086/324033 |bibcode=2002ApJ...564..421B |s2cid=9273465 }}
{{cite journal |last=Dahn |first=C. C. |author2=Harris, Hugh C. |author3=Vrba, Frederick J. |author4=Guetter, Harry H. |author5=Canzian, Blaise |author6=Henden, Arne A. |author7=Levine, Stephen E. |author8=Luginbuhl, Christian B. |author9=Monet, Alice K. B. |author10=Monet, David G. |author11=Pier, Jeffrey R. |author12=Stone, Ronald C. |author13=Walker, Richard L. |author14=Burgasser, Adam J. |author15=Gizis, John E. |author16=Kirkpatrick, J. Davy |author17=Liebert, James |author18=Reid, I. Neill |title=Astrometry and Photometry for Cool Dwarfs and Brown Dwarfs |year=2002 |journal=The Astronomical Journal |volume=124 | issue=2 | pages=1170–1189 |arxiv=astro-ph/0205050 |doi=10.1086/341646 |bibcode=2002AJ....124.1170D|s2cid=119485007 }}
Dictionary of Nomenclature of Celestial Objects. [http://cds.u-strasbg.fr/cgi-bin/Dic-Simbad?GD GD entry]. SIMBAD. Centre de Données astronomiques de Strasbourg.
}}
{{Stars of Boötes}}