HD 39118

Coordinates: Sky map 05h 50m 30s, +02° 01′ 28.9″
Source: Wikipedia, the free encyclopedia.
(Redirected from
HR 2024
)
HD 39118

Basic layout of the HR 2024 system.
Observation data
Epoch J2000      Equinox J2000
Constellation Orion[a]
Right ascension 05h 50m 30.03s[1]
Declination 02° 01′ 28.93″[1]
Apparent magnitude (V) 5.976[1]
Characteristics
Cool primary
Evolutionary stage
Red giant branch[2]
Spectral type K0II[3]
Apparent magnitude (B) 6.83±0.015[1]
Apparent magnitude (G) 5.64[1]
Apparent magnitude (J) 4.193±0.238[1]
Apparent magnitude (H) 3.502±0.194[1]
Apparent magnitude (K) 3.337±0.19[1]
B−V color index 1.12[3]
Hot secondary
Evolutionary stage B-type main-sequence star + A-type main-sequence star
Spectral type B7V/B8V + A0V[3]
B−V color index -0.09[3]
Distance
2300+350
−270 ly
(707.6+107
−83.3 pc)[4]
Absolute magnitude (MV)–2.53
(–2.3 (primary) + –0.75 (secondary))[3]
Eccentricity (e)
0.3±0.007[5]
Details
K-type giant
Myr
B-type star
Temperature11,300[9] K
TYC 120-877-1, GSC 00120-00877, IRAS 05478+0200, 2MASS
J05503003+0201290
Database references
SIMBADdata

HD 39118 (HD 39119, HR 2024) is a

K-type giant star) and a hot secondary, which is a binary star formed from a B-type main-sequence star and an A-type main-sequence star. A 2021 estimate derive a distance of 708 parsecs (2,310 ly) to HD 39118, and it is moving away from Earth at a speed of 4.24 km/s. The apparent magnitude is 5.976, making it visible to the naked eye only from dark skies
.

Characteristics

HR 2024 is a

spectroscopic binary (more precisely a single-lined spectroscopic binary)[10] made up of a cool primary and a hot secondary, which is also a binary star.[3] The designations “cold” and “hot” refer to the effective temperature of the components. They are separated by 4.7×108 kilometres (3.1 AU), and complete an orbit around each other every 2,570 days (7 years).[5] The orbital eccentricity is equivalent to 0.3.[5]

HD 39118 can be seen in the northern celestial hemisphere, close to the celestial equator, at a distance of 708 parsecs (2,310 light-years) in the constellation Orion.[1][4][b] It has an apparent magnitude of 5.976.[1] At this magnitude, it is visible to the naked eye only in dark skies, being close to the limiting magnitude to naked-eye vision of 6.5.[11] The absolute magnitude, i.e. its brightness if it was seen at a distance or 10 parsecs (32.6 ly), is –2.53.[3] It is moving away from Earth at a velocity of 4.24 km/s.[1]

It was double cataloged in the Henry Draper Catalogue, receiving the designations HD 39118 and HD 39119.[1]

Primary star

The primary has an

K-type star.[e]

Hot companion

The hot companion is made up of two other stars, one is a

B-type star.[e]

Notes

  1. ^ Obtained with a right ascension of 05h 50m 30.03s and a declination of +02° 01′ 28.9″ on this website.
  2. ^ Constellation obtained with SIMBAD's celestial coordinates placed on this website
  3. ^ The Sun's effective temperature is 5772 K.
  4. ^ From a logarithm of -0.34
  5. ^ a b See the color index article

References

  1. ^ a b c d e f g h i j k l m "BD+01 1148". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved May 6, 2024.
  2. ^
    ISSN 0004-6361. HD 39118's database entry
    at VizieR.
  3. ^
    ISSN 0067-0049
    .
  4. ^
    ISSN 0004-6256. Data about this star can be seen here
    .
  5. ^
    ISSN 0250-6335
    .
  6. ^
    ISSN 0035-8711. HD 39118's database entry
    at VizieR.
  7. ^
    ISSN 0004-6361. HD 39118's database entry
    at VizieR.
  8. ^
    ISSN 0004-6361. HD 39118's database entry
    at VizieR.
  9. ^
    ISSN 0004-6361. HD 39118's database entry
    at VizieR.
  10. ISSN 0365-0138
    .
  11. ^ "Determining the Limiting Magnitude – Saguaro Astronomy Club". www.saguaroastro.org. Retrieved 2024-05-21.
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