LP 658-2

{{Short description|White dwarf star in the constellation Orion}}

{{Starbox begin

| name = LP 658-2

}}

{{Starbox observe

| epoch = J2000.0

| equinox = J2000.0 (ICRS)

| constell = Orion

| ra = {{RA|05|55|09.53049}}

| dec = {{DEC|−04|10|07.0653}}

| appmag_v=14.488{{cite journal |last1=Holberg |first1=J. B. |last2=Sion |first2=E. M. |last3=Oswalt |first3=T. |last4=McCook |first4=G. P. |last5=Foran |first5=S. |last6=Subasavage |first6=John P. |title=A new look at the local white dwarf population |journal=The Astronomical Journal |date=1 April 2008 |volume=135 |issue=4 |pages=1225–1238 |bibcode=2008AJ....135.1225H |doi=10.1088/0004-6256/135/4/1225|doi-access=free }}

}}

{{Starbox character

| class = DZ11.8

| appmag_1_passband=B

| appmag_1=15.49

| appmag_2_passband=V

| appmag_2=14.488

| appmag_3_passband=R_KC

| appmag_3=13.99{{cite journal |last1=Subasavage |first1=John P. |last2=Jao |first2=Wei-Chun |last3=Henry |first3=Todd J. |last4=Bergeron |first4=P. |last5=Dufour |first5=P. |last6=Ianna |first6=Philip A. |last7=Costa |first7=Edgardo |last8=Méndez |first8=René A. |title=The solar neighborhood. XXI. Parallax results from the CTIOPI 0.9 m program: 20 new members of the 25 parsec white dwarf sample |journal=The Astronomical Journal |date=1 June 2009 |volume=137 |issue=6 |pages=4547–4560 |bibcode=2009AJ....137.4547S |doi=10.1088/0004-6256/137/6/4547|arxiv=0902.0627 |s2cid=14696597 }}

| appmag_4_passband=I_KC

| appmag_4=13.51

| appmag_5_passband=J

| appmag_5=13.05 ± 0.03

| appmag_6_passband=H

| appmag_6=12.86 ± 0.03

| appmag_7_passband=K_S

| appmag_7=12.78 ± 0.03

| b-v = 1.0

}}

{{Starbox astrometry

| prop_mo_ra = {{val|535.249}}

| prop_mo_dec = {{val|-2317.011|fmt=commas}}

| pm_footnote =

| parallax = 155.2373

| p_error = 0.0175

| parallax_footnote =

| absmag_v=15.44 ± 0.03

}}

{{Starbox detail

| component1=From Holberg etal. (2008)

| source=

| mass={{val|0.45|0.01}}

| gravity={{val|7.80|0.02}}

| radius=0.014From surface gravity and mass.

| temperature={{val|4270|70|fmt=commas}},

| age_gyr=6.42{{cite journal |last1=Sion |first1=Edward M. |last2=Holberg |first2=J. B. |last3=Oswalt |first3=Terry D. |last4=McCook |first4=George P. |last5=Wasatonic |first5=Richard |title=The white dwarfs within 20 parsecs of the Sun: kinematics and statistics |journal=The Astronomical Journal |date=1 December 2009 |volume=138 |issue=6 |pages=1681–1689 |arxiv=0910.1288 |bibcode=2009AJ....138.1681S |doi=10.1088/0004-6256/138/6/1681|s2cid=119284418 }}

}}

{{Starbox detail

| component1 = From Subasavage etal. (2009)

| source=

| mass={{val|0.80|0.01}}

| gravity={{val|8.35|0.01}}

| radius=0.010

| temperature={{val|5180|70|fmt=commas}}

| age_gyr={{val|6.82|0.02}}White dwarf cooling age, i. e. age as degenerate star (not including lifetime as main sequence star and as giant star)

}}

{{Starbox catalog

| names={{odlist | name=HL 4 | EGGR=45 | G=99-44 | G2=106-12 | GJ=223.2 | GJ2=9193 | LHS=32 | LP=658-2 | NLTT=15811 | WD=0552-041}}

}}

{{Starbox reference

| Simbad=GJ+223.2

}}

LP 658-2 is a degenerate (white dwarf) star in the constellation of Orion, the single known object in its system. It has an apparent visual magnitude of approximately 14.488.

Distance

According to a 2009 paper, it is the eighth closest known white dwarf to the Sun (after Sirius B, Procyon B, van Maanen's star, Gliese 440, 40 Eridani B, Stein 2051 B and GJ 1221).Table 1 in {{harvnb|Sion|Holberg|Oswalt|McCook|2009}} Its trigonometric parallax from the CTIOPI (Cerro Tololo Inter-American Observatory (CTIO) Parallax Investigation) 0.9 m telescope program, published in 2009, is 0.15613 ± 0.00084 arcsec, corresponding to a distance 6.40 ± 0.03 pc, or 20.89 ± 0.11 ly. Also, previous less precise parallax measurements of LP 658-2 present in YPC (Yale Parallax Catalog) and among results of CTIOPI 1.5 m telescope program:

LP 658-2 parallax measurements

Source	Paper	Parallax, mas	Distance, pc	Distance, ly	Ref.
class="wikitable"
YPC	van Altena et al., 1995	155.0 ± 2.1	6.45 ± 0.09	21.04 ± 0.29
CTIOPI 1.5 m	TSN-14 (Costa et al., 2005)	156.93 ± 2.67	6.37 ± 0.11	20.78 ± 0.35	{{cite journal \|last1=Costa \|first1=Edgardo \|last2=Méndez \|first2=René A. \|last3=Jao \|first3=W.-C. \|last4=Henry \|first4=Todd J. \|last5=Subasavage \|first5=John P. \|last6=Brown \|first6=Misty A. \|last7=Ianna \|first7=Philip A. \|last8=Bartlett \|first8=Jennifer\|author8-link=Jennifer Bartlett (astronomer) \|title=The solar neighborhood. XIV. Parallaxes from the Cerro Tololo Inter-American Observatory Parallax Investigation—First results from the 1.5 m telescope program \|journal=The Astronomical Journal \|date=July 2005 \|volume=130 \|issue=1 \|pages=337–349 \|bibcode=2005AJ....130..337C \|doi=10.1086/430473\|doi-access=free \|hdl=10533/176842 \|hdl-access=free }}
CTIOPI 0.9 m	TSN-21 (Subasavage et al., 2009)	156.13 ± 0.84	6.40 ± 0.03	20.89 ± 0.11

Physical parameters

There are two sets of published physical parameters of LP 658-2, significantly differing from each other: one from {{harvnb|Holberg|Sion|Oswalt|McCook|2008}} and {{harvnb|Sion|Holberg|Oswalt|McCook|2009}}, the other from {{harvnb|Subasavage|Jao|Henry|Bergeron|2009}}.

=Color=

Despite it being classified as a "white" dwarf, it appears yellowish white rather than white, due to temperature, cooler than the Sun's and comparable with that of a K-type main sequence star.

Notes

References

{{reflist|refs=

{{cite book |last1=van Altena |first1=W. F. |last2=Lee |first2=J. T. |last3=Hoffleit |first3=E. D. |title=The General Catalogue of Trigonometric [Stellar] Parallaxes |date=1995 |publisher=Yale University Observatory |location=New Haven, CT |edition=4th |bibcode=1995gcts.book.....V}} [http://vizier.cfa.harvard.edu/viz-bin/VizieR?-source=I/238 VizieR entry].

}}

Category:Orion (constellation)

Category:White dwarfs

0223.2