Gliese 687

Star in the constellation Draco

Gliese 687

Gliese 687 is the small orange star located in the center of the above image.

Observation data
Epoch J2000 Equinox J2000
Constellation | Draco
Right ascension | 17h 36m 25.89931s[1]
Declination | +68° 20′ 20.9096″[1]
Apparent magnitude (V) | 9.15[2]
Characteristics
Spectral type | M3.5 V[3]
U−B color index | 1.06
B−V color index | 1.49
Astrometry
Radial velocity (Rv)| −28.90±0.13[1] km/s
Proper motion (μ)|  RA: –320.675 mas/yr[1]
Dec.: –1269.893 mas/yr[1]
Parallax (π)| 219.7898±0.0210 mas[1]
Distance| 14.839 ± 0.001 ly
(4.5498 ± 0.0004 pc)
Absolute magnitude (MV)| 10.87
Details
Mass| 0.40±0.02[4] M☉
Radius| 0.4183±0.0070[5] R☉
Luminosity| 0.02128±0.00023[5] L☉
Surface gravity (log g)| 4.66[6] cgs
Temperature| 3,413±28[5] K
Metallicity [Fe/H]| +0.11 ± 0.20[6] dex
Rotation| 61.8±1.0 d[7]
Rotational velocity (v sin i)| <2.8[8] km/s
Other designations
BD+68 946, GJ 687, HIP 86162, SAO 17568, LHS 450, LTT 15232, PLX 4029.00[2]
Database references
SIMBAD| data
Exoplanet Archive| data

Gliese 687

Location of Gliese 687 in the constellation Draco

Gliese 687, or GJ 687 (Gliese–Jahreiß 687) is a red dwarf in the constellation Draco. This is one of the closest stars to the Sun and lies at a distance of 14.84 light-years (4.55 parsecs). Even though it is close by, it has an apparent magnitude of about 9, so it can only be seen through a moderately sized telescope. Gliese 687 has a high proper motion, advancing 1.304 arcseconds per year across the sky. It has a net relative velocity of about 39 km/s.[2] It is known to have a Neptune-mass planet.[7] Old books and articles refer to it as Argelander Oeltzen 17415.[9]

## Properties

[edit]

Gliese 687 has about 40% of the Sun's mass and nearly 50% of the Sun's radius. Compared to the Sun, it has a slightly higher proportion of elements with higher atomic numbers than helium.[6] It seems to rotate every 60 days and exhibit some chromospheric activity.

It displays no excess of infrared radiation that would indicate orbiting dust.[10]

Gliese 687 is a solitary red dwarf that emits X-rays.[11]

## Planetary system

[edit]

In 2014, Gliese 687 was discovered to have a planet, Gliese 687 b, with a minimum mass of 18.394 Earth masses (which makes it comparable to Neptune), an orbital period of 38.14 days, a low orbital eccentricity and inside the habitable zone.[7] Another Neptune-mass planet candidate was discovered in 2020, in a further out and much colder orbit.[4]

The Gliese 687 planetary system[4] Companion
(in order from star) | Mass | Semimajor axis
(AU) | Orbital period
(days) | Eccentricity | Inclination | Radius

|
|
|
|
|
|

b | ≥17.2±1.0 M🜨 | 0.163±0.003 | 38.142±0.007 | 0.17±0.05 | —  | —
c | ≥16.0±4.1 M🜨 | 1.165±0.023 | 727.562±12.198 | 0.40±0.22 | —  | —

## See also

[edit]

* List of nearest stars and brown dwarfs
* List of exoplanets discovered in 2014 \- Gliese 687 b
* List of exoplanets discovered in 2020 \- Gliese 687 c

## References

[edit]

1. ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
2. ^ a b c "LHS 450 -- High proper-motion Star". SIMBAD. Centre de Données astronomiques de Strasbourg. Archived from the original on 2017-11-09. Retrieved 2009-11-12.
3. ^ Endl, Michael; Cochran, William D.; Kürster, Martin; Paulson, Diane B.; Wittenmyer, Robert A.; MacQueen, Phillip J.; Tull, Robert G. (September 2006). "Exploring the Frequency of Close-in Jovian Planets around M Dwarfs". The Astrophysical Journal. 649 (1): 436–443\. arXiv:astro-ph/0606121. Bibcode:2006ApJ...649..436E. doi:10.1086/506465. S2CID 14461746.
4. ^ a b c Feng, Fabo; Shectman, Stephen A.; Clement, Matthew S.; Vogt, Steven S.; Tuomi, Mikko; Teske, Johanna K.; Burt, Jennifer; Crane, Jeffrey D.; Holden, Bradford; Sharon Xuesong Wang; Thompson, Ian B.; Diaz, Matias R.; Paul Butler, R. (2020). "Search for Nearby Earth Analogs. III. Detection of ten new planets, three planet candidates, and confirmation of three planets around eleven nearby M dwarfs". The Astrophysical Journal Supplement Series. 250 (2): 29. arXiv:2008.07998. Bibcode:2020ApJS..250...29F. doi:10.3847/1538-4365/abb139. S2CID 221150644.
5. ^ a b c Boyajian, Tabetha S.; et al. (2012). "Stellar Diameters and Temperatures. Ii. Main-Sequence K- and M-Stars". The Astrophysical Journal. 757 (2): 112. arXiv:1208.2431. Bibcode:2012ApJ...757..112B. doi:10.1088/0004-637X/757/2/112. ISSN 0004-637X.
6. ^ a b c Berger, D. H.; et al. (2006). "First Results from the CHARA Array. IV. The Interferometric Radii of Low-Mass Stars". The Astrophysical Journal. 644 (1): 475–483\. arXiv:astro-ph/0602105. Bibcode:2006ApJ...644..475B. doi:10.1086/503318. S2CID 14966363.
7. ^ a b c Burt, Jennifer; Vogt, Steven S.; Butler, R. Paul; Hanson, Russell; Meschiari, Stefano; Rivera, Eugenio J.; Henry, Gregory W.; Laughlin, Gregory (2014). "The Lick–Carnegie exoplanet survey: Gliese 687 b: A Neptune-mass planet orbiting a nearby red dwarf". The Astrophysical Journal. 789 (2): 114. arXiv:1405.2929. Bibcode:2014ApJ...789..114B. doi:10.1088/0004-637X/789/2/114. S2CID 17668957.
8. ^ Jenkins, J. S.; Ramsey, L. W.; Jones, H. R. A.; Pavlenko, Y.; Gallardo, J.; Barnes, J. R.; Pinfield, D. J. (October 2009). "Rotational Velocities for M Dwarfs". The Astrophysical Journal. 704 (2): 975–988\. arXiv:0908.4092. Bibcode:2009ApJ...704..975J. doi:10.1088/0004-637X/704/2/975. S2CID 119203469.
9. ^ Lynn, W. T. (June 1890). "On the proper motions of three stars". Monthly Notices of the Royal Astronomical Society. 50 (8): 519–520\. Bibcode:1890MNRAS..50..519L. doi:10.1093/mnras/50.8.519.
10. ^ Gautier, Thomas N., III; et al. (September 2007). "Far-Infrared Properties of M Dwarfs". The Astrophysical Journal. 667 (1): 527–536\. arXiv:0707.0464. Bibcode:2007ApJ...667..527G. doi:10.1086/520667. S2CID 15732144.
11. ^ Schmitt JHMM; Fleming TA; Giampapa MS (September 1995). "The X-ray view of the low-mass stars in the solar neighborhood". Astrophys. J. 450 (9): 392–400\. Bibcode:1995ApJ...450..392S. doi:10.1086/176149.

## External links

[edit]

* NEXXUS page Archived 2012-02-22 at the Wayback Machine

* v
* t
* e

← Celestial objects within 10–15 light-years →

| Primary member type|

Celestial objects by systems.

| Subgiant stars|

| F-type|

* Procyon (Alpha Canis Minoris) (11.402±0.032 ly)
* white dwarf B

|

| Main-sequence
stars|

| G-type|

* Tau Ceti (11.9118±0.0074 ly)
* 4 (8?) planets: (b), (c), (d), e, f, g, h, (i)

|

K-type|

* Epsilon Eridani (Ran) (10.4749±0.0037 ly)
* 1 (2?) planets: b (Ægir), c?
* 61 Cygni (11.4039±0.0012 ly)
* K-type main-sequence star B
* Epsilon Indi (11.8670±0.0041 ly)
* 2 T-type brown dwarfs: Ba, Bb
* planet Ab

M-type
(red dwarfs)|

* Ross 248 (10.3057±0.0014 ly)
* Lacaille 9352 (10.7241±0.0007 ly)
* 2 (3?) planets: b, c, d?
* Ross 128 (11.0074±0.0011 ly)
* planet b
* EZ Aquarii (11.109±0.034 ly)
* 2 red dwarfs: B, C
* Struve 2398 (11.4908±0.0009 ly)
* red dwarf B
* 1 (3?) planets: Ab, Bb?, Bc?
* Groombridge 34 (11.6191±0.0008 ly)
* red dwarf B
* 2 planets: Ab, Ac
* DX Cancri (11.6797±0.0027 ly)
* GJ 1061 (11.9839±0.0014 ly)
* 3 planets: b, c, d
* YZ Ceti (12.1222±0.0015 ly)
* 3 planets: b, c, d
* Luyten's Star (12.3485±0.0019 ly)
* 2 (4?) planets: b, c, d?, e?
* Teegarden's Star (12.4970±0.0045 ly)
* 3 planets: b, c, d
* Kapteyn's Star (12.8308±0.0008 ly)
* Lacaille 8760 (12.9472±0.0018 ly)
* SCR 1845−6357 (13.0638±0.0070 ly)
* T-type brown dwarf B
* Kruger 60 (13.0724±0.0052 ly)
* red dwarf B
* DENIS J1048−3956 (13.1932±0.0027 ly)
* Ross 614 (13.363±0.040 ly)
* red dwarf B
* Wolf 1061 (14.0500±0.0016 ly)
* 3 planets: b, c, d
* Gliese 1 (14.1747±0.0022 ly)
* TZ Arietis (14.5780±0.0046 ly)
* planet b
* Wolf 424 (14.595±0.031 ly)
* red dwarf B
* Gliese 687 (14.8395±0.0014 ly)
* 2 planets: b, c
* Gliese 674 (14.8492±0.0018 ly)
* planet b
* LHS 292 (14.8706±0.0041 ly)

| Degenerate
stars|

| White dwarfs|

* van Maanen 2 (14.0718±0.0011 ly)

|

| Brown dwarfs|

| T-type|

* UGPS J0722-0540 (13.43±0.13 ly)

|

* v
* t
* e

Constellation of Draco

* List of stars in Draco
* Draco in Chinese astronomy

Stars|

| Bayer|

* α (Thuban)
* β (Rastaban)
* γ (Eltanin)
* δ (Altais)
* ε (Tyl)
* ζ (Aldhibah)
* η (Athebyne)
* θ
* ι (Edasich)
* κ
* λ (Giausar)
* μ (Alrakis)
* ν (Kuma)
* ξ (Grumium)
* ο
* π
* ρ
* σ (Alsafi)
* τ
* υ
* φ
* χ
* ψ1 (Dziban)
* ψ2
* ω

|

Flamsteed|

* 6
* 7 (Tianyi)
* 8 (Taiyi)
* 10 (i)
* 15 (A)
* 18 (g)
* 19 (h)
* 26
* 36
* 39 (b)
* 42 (Fafnir)
* 45 (d)
* 64 (e)
* 68

Variable|

* TW
* AG
* BY
* CL
* CM
* CX
* DO
* V581

HR|

* 3751
* 4126
* 4934
* 5811
* 6237
* 6618 (Alruba)
* 6817
* 7137
* 7783

HD|

* 101364
* 147379
* 156279
* 158259
* 176693
* 191939

Other|

* 2MASS 1237+6526
* 2MASS J17554042+6551277
* G 240-72
* GD 356
* Gliese 420
* Gliese 625
* Gliese 687
* GRW +70 8247
* Kepler-4
* Kepler-10
* Kepler-12
* Kepler-90
* Kepler-296
* LP 71-82
* Qatar-1
* Struve 2398
* TOI-1136
* TrES-2A
* WISE 1647+5632

| Exoplanets|

* 42 Dra b (Orbitar)
* HD 139357 b
* HD 167042 b
* ι Dra b (Hypatia)
* Kepler-4b
* Kepler-10b
* c
* Kepler-12b
* Kepler-90e
* f
* g
* h
* i
* TOI-1452 b
* TrES-2b

|

| Star clusters|

* LAMOST 1

|

| Nebulae|

* Abell 50
* Cat's Eye Nebula

|

Galaxies|

| NGC|

* 3147
* 4121
* 4125
* 4236
* 4319
* 4345
* 4513
* 4589
* 5678
* 5777
* 5866
* 5866B
* 5879
* 5906
* 5907
* 5949
* 5963
* 5965
* 5982
* 5985
* 6090
* 6248
* 6285
* 6286
* 6338
* 6340
* 6365
* 6373
* 6394
* 6412
* 6503
* 6505
* 6566
* 6621
* 6622
* 6670
* 6676
* 6786
* 6789

|

Other|

* 1ES 1927+654
* 1ES 1959+650
* 3C 249.1
* 3C 305
* 3C 319
* 3C 356
* 3C 371
* 3C 380
* 3C 390.3
* 3C 401
* 4C +72.26
* GB 1508+5714
* H1821+643
* HFLS3
* KKR 25
* Markarian 876
* PGC 39058
* S5 1803+784
* S5 2007+777
* UGC 9391

| Galaxy clusters|

* Abell 2218
* CL1358+62
* Draco Supercluster

|

| Astronomical events|

* Swift J1644+57
* SN 2005B
* SN 2016aps

|

Category
*[RA:]: Right Ascension
*[Dec.:]: Declination
*[v]: View this template
*[t]: Discuss this template
*[e]: Edit this template
*[Primary]: Primary member of a system is the brightest one (and, in most cases, also the most massive one).