2025AJ....170..316O

Query : 2025AJ....170..316O

2025AJ....170..316O - Astron. J., 170, 316 (2025/December-0)

NGTS-EB-8: A Double-lined Eclipsing M+M Binary Discovered by Citizen Scientists.

O'BRIEN S.M., SCHWAMB M.E., WATSON C.A., NIELSEN L.D., BRYANT E.M., CASEWELL S.L., BURLEIGH M.R., FORTSON L., GILL S., LINTOTT C.J., HOBBS K.L., APERGIS I., BAYLISS D., FERNANDEZ FERNANDEZ J., GUNTHER M.N., HAWTHORN F., JENKINS J.S., KENDALL A., McCORMAC J., DE MOOIJ E.J.W., RODEL T., SAHA S., TROUILLE L., WEST R.G., WHEATLEY P.J., AGAFITEI M.C., APAYDIN D.R., BAETEN E., BALLER B., CARABOTT J., CHESSON S., FREIGEIRO S.A., GONANO V., HANKE M., HERMES P., HILDEBRAND A., LANGLEY J.S., LIM S.M., McCARTHY L.R., MITCHELL G., O'NEILL K., PEARSON C.R., REKET N., RIETHMILLER J., SAEFTEL J., SAINIO A., STEINER C., STRICKLAND A., TANNER C., TERENTEV I.A., TIU E.J.P., TUMANOV S.Y., URSZULA M., VAHLENKAMP P., DE VROOME F., WANTUCH P. and WOODRUFF T.

Abstract (from CDS):

We report the identification and characterization of a new binary system composed of two near-equal mass M-dwarfs. The binary NGTS-EB-8 was identified as a planet candidate in data from the Next Generation Transit Survey (NGTS) by citizen scientists participating in the Planet Hunters NGTS project. High-resolution spectroscopic observations reveal the system to be a double-lined binary. By modeling the photometric and radial velocity observations, we determine an orbital period of 4.2 days and the masses and radii of both stars to be ${M}_{A}=0.25{0}_{-0.004}^{+0.005}$M⊙, ${M}_{B}=0.20{8}_{-0.004}^{+0.005}$M⊙, and ${R}_{A}=0.25{5}_{-0.005}^{+0.004}$R⊙, ${R}_{B}=0.23{3}_{-0.005}^{+0.006}$R⊙, respectively. We detect Balmer line emission from at least one of the stars but no significant flare activity. We note that both components lie in the fully convective regime of low-mass stars (≲0.35 M⊙); therefore, they can be a valuable test for stellar evolutionary models. We demonstrate that the photometric observations, speckle imaging, and initial radial velocity measurements were unable to identify the true nature of this system and highlight that high-resolution spectroscopic observations are crucial in determining whether systems such as this are in fact binaries.

Abstract Copyright: © 2025. The Author(s). Published by the American Astronomical Society.

Journal keyword(s): Eclipsing binary stars - Transit photometry - M dwarf stars

Status at CDS : Large table(s) will be appraised for possible ingestion in VizieR. // All or part of tables of objects will be ingested in SIMBAD with priority 1.

Simbad objects: 34

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Number of rows : 34
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 2MASS J00024841-2953539 EB* 00 02 48.4315088952 -29 53 53.947671288     17.46     ~ 16 0
2 NAME SDSS-MEB-1 SB* 03 18 23.8769202096 -01 00 18.413811144         16.91 ~ 27 0
3 2MASS J03262072+0312362 EB* 03 26 20.7332788080 +03 12 36.343146636           ~ 22 0
4 LP 54-19 SB* 03 37 14.0817987048 +69 10 49.779443244   15.5   13.991   dM4.5 68 0
5 TOI-450 * 05 16 01.1795343984 -31 24 45.685796040   16.918 15.295 15.003   ~ 14 0
6 2MASS J05221817-2507112 EB* 05 22 18.1714703592 -25 07 11.193636180   18.19   15.81 13.69 M4-5+M4-5 10 0
7 LP 837-20 EB* 05 44 57.9330491832 -24 56 09.713268096   17.294 15.539 15.363   M4.5Ve 22 0
8 CVSO 1975 TT* 05 52 55.7204335992 -00 44 26.713737672     13.45     M3.5e 14 0
9 LP 661-13 SB* 06 56 18.9454767864 -08 35 46.512397860     13.97 12.76 11.17 dM4.5 38 0
10 V* YY Gem SB* 07 34 37.4474327544 +31 52 10.179641496 11.60 10.56 9.27 7.69 6.67 M0.5VeFe-2 882 0
11 2MASS J07431157+0316220 EB* 07 43 11.5724519136 +03 16 22.101307392       16.02   ~ 20 0
12 LP 208-19 LM* 08 03 23.0523185352 +39 30 55.573882308   19.0   16.8   M4.0 14 0
13 V* CU Cnc SB* 08 31 37.5741841080 +19 23 39.398029332   12.83 11.809 11.592   M5Ve 237 0
14 Cl* NGC 2682 FBC 2136 EB* 08 50 32.9548840200 +12 08 23.631964152   17.51 16.35 15.36 13.61 M3.2 22 0
15 2MASS J08504984+1948364 EB* 08 50 49.8423820800 +19 48 36.547637508           M5V 50 0
16 TOI-2603 * 09 30 16.0361951904 -18 50 35.315080512   16.629 15.296 15.397   M1.0 6 0
17 2MASS J10305521+0334265 EB* 10 30 55.2108147768 +03 34 26.723215200           ~ 21 0
18 TOI-762 PM* 11 04 18.1831086079 -47 49 17.003005092   17.891 16.110     ~ 13 0
19 FBS 1109+767 EB* 11 12 42.3396641760 +76 26 56.387535288   16.1   14.8   M4V 57 0
20 2MASS J11551666-4008570 PM* 11 55 16.6680230347 -40 08 57.067405925     16.365     ~ 4 0
21 HD 108770 * 12 30 00.6484204608 -38 20 21.068488464   8.30 8.29     A0V 13 0
22 LP 133-373 EB* 14 04 08.8829131392 +50 20 38.642975844   16.3   15.2   ~ 27 0
23 G 179-55 EB* 15 47 27.4119372390 +45 07 51.345516619   15.20 13.61 13.246   M4Ve 59 0
24 UScoCTIO 5 Or* 15 59 50.5086047328 -19 44 37.368190320           M4e 54 0
25 DENIS J161630.6-251220 LM* 16 16 30.6738768240 -25 12 20.215798956   19.5   17.3 15.042 M4.5V-M5V+M4.5V-M5V 44 0
26 V* CM Dra BY* 16 34 20.3302660573 +57 09 44.368918696   14.50 12.87 10.85 9.26 M4.5V 467 0
27 WTS 17e-3-02003 V* 17 13 01.2430119408 +03 50 40.226544888   19.88 18.54 17.68 16.77 ~ 2 0
28 WTS 17h-4-01429 V* 17 15 39.6138859944 +03 47 09.666152340       19.30 17.34 ~ 2 0
29 Kepler-16 SB* 19 16 18.1758378936 +51 45 26.782726104   12.1   11.90   K7V 274 1
30 2MASS J19350355+3631165 EB* 19 35 03.5536693080 +36 31 16.532966172           M 19 0
31 2MASS J19371357+3648541 EB* 19 37 13.5755800776 +36 48 54.226877796           ~ 5 0
32 Kepler-469b Pl 19 49 54.2016372336 +41 06 51.428433708           ~ 3 0
33 UCAC4 260-197941 * 21 43 58.6002420648 -38 01 02.736481944   16.39   14.98 12.92 M3+M3 5 0
34 2MASS J23143816+0339493 EB* 23 14 38.1601778232 +03 39 49.367823156       16.67   ~ 25 0

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